chore: ignore MagicMock test artifacts

Co-authored-by: CommandCodeBot <noreply@commandcode.ai>

.gitignore

@@ -18,3 +18,4 @@ json
 src/fenris.egg-info/
 .pytest_cache/
 .venv/
+MagicMock*

Makefile

@@ -93,6 +93,12 @@ install: check-python check-smartctl dist/fenris-*.whl
 	@sudo install -m 0644 units/fenris-collect.service $(UNIT_DIR)/
 	@sudo systemctl daemon-reload
 	
+	@echo "=== Installing runit service files (dormant — not enabled) ==="
+	@sudo install -d -m 0755 /etc/sv/fenris-collect/log
+	@sudo install -m 0755 units/runit/fenris-collect/run /etc/sv/fenris-collect/run
+	@sudo install -m 0755 units/runit/fenris-collect/log/run /etc/sv/fenris-collect/log/run
+	@sudo touch /etc/sv/fenris-collect/down
+	
 	@echo "=== Installing polkit policy ==="
 	@sudo install -m 0644 polkit/com.bongbetic.fenris.monitor.policy $(POLKIT_DIR)/
 	
@@ -143,6 +149,9 @@ upgrade: dist/fenris-*.whl
 	@echo "=== Syncing units against manifest ==="
 	@sudo install -m 0644 units/fenris-collect.timer $(UNIT_DIR)/
 	@sudo install -m 0644 units/fenris-collect.service $(UNIT_DIR)/
+	@sudo install -d -m 0755 /etc/sv/fenris-collect/log
+	@sudo install -m 0755 units/runit/fenris-collect/run /etc/sv/fenris-collect/run
+	@sudo install -m 0755 units/runit/fenris-collect/log/run /etc/sv/fenris-collect/log/run
 	@sudo install -m 0644 polkit/com.bongbetic.fenris.monitor.policy $(POLKIT_DIR)/
 	@sudo install -m 0755 scripts/fenris $(BIN_DIR)/fenris
 	@sudo install -m 0755 src/fenris/monitor.py $(LIBEXEC_DIR)/fenris-monitor
@@ -196,6 +205,9 @@ uninstall:
 	@sudo systemctl stop fenris-collect.timer 2>/dev/null || true
 	@sudo systemctl disable fenris-collect.timer 2>/dev/null || true
 	@sudo systemctl daemon-reload
+	@-sudo rm -f /var/service/fenris-collect 2>/dev/null || true
+	@-sudo rm -rf /etc/sv/fenris-collect 2>/dev/null || true
+	@-sudo rm -rf /var/log/fenris-collect 2>/dev/null || true
 	
 	@echo "=== Removing installed files (preserving config and store) ==="
 	@-rm -f $(BIN_DIR)/fenris

packaging/postinst.sh

@@ -12,10 +12,17 @@ STORE_BAK="${STORE_DIR}/observations.db.bak"
 RUNTIME_PYTHON="/usr/bin/python3"
 VENDOR_DIR="/opt/fenris/vendor"
 
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
 case "${1:-}" in
     configure)
         if [ -n "${2:-}" ]; then
-            # Upgrade — snapshot, migration, daemon-reload, conditional timer restart
+            # Upgrade — snapshot, migration, init-system-aware reload
             if [ -f "${STORE_DB}" ]; then
                 cp "${STORE_DB}" "${STORE_BAK}" 2>/dev/null || true
             fi
@@ -27,29 +34,44 @@ n = migrate_to_latest(Path('${STORE_DB}'))
 print(f'Fenris migration: {n} step(s) applied') if n else None
 " 2>&1 || echo "Fenris: migration skipped (store not yet initialized)"
             fi
-            # Capture running unit content BEFORE daemon-reload (spec §7)
-            RUNNING_UNITS=""
-            for unit in fenris-collect.timer; do
-                if systemctl is-active --quiet "${unit}" 2>/dev/null; then
-                    RUNNING_UNITS="${RUNNING_UNITS} ${unit}"
-                fi
-            done
-            systemctl daemon-reload 2>/dev/null || true
-            # Restart timer only if unit contents changed AND active
-            for unit in ${RUNNING_UNITS}; do
-                OLD_CONTENT="$(mktemp)"
-                NEW_PATH="/usr/lib/systemd/system/${unit}"
-                systemctl cat "${unit}" > "${OLD_CONTENT}" 2>/dev/null || true
-                if ! diff -q "${OLD_CONTENT}" "${NEW_PATH}" > /dev/null 2>&1; then
-                    systemctl restart "${unit}" 2>/dev/null || true
-                fi
-                rm -f "${OLD_CONTENT}"
-            done
+            if [ "${INIT_SYSTEM}" = "systemd" ]; then
+                # Capture running unit content BEFORE daemon-reload (spec §7)
+                RUNNING_UNITS=""
+                for unit in fenris-collect.timer; do
+                    if systemctl is-active --quiet "${unit}" 2>/dev/null; then
+                        RUNNING_UNITS="${RUNNING_UNITS} ${unit}"
+                    fi
+                done
+                systemctl daemon-reload 2>/dev/null || true
+                # Restart timer only if unit contents changed AND active
+                for unit in ${RUNNING_UNITS}; do
+                    OLD_CONTENT="$(mktemp)"
+                    NEW_PATH="/usr/lib/systemd/system/${unit}"
+                    systemctl cat "${unit}" > "${OLD_CONTENT}" 2>/dev/null || true
+                    if ! diff -q "${OLD_CONTENT}" "${NEW_PATH}" > /dev/null 2>&1; then
+                        systemctl restart "${unit}" 2>/dev/null || true
+                    fi
+                    rm -f "${OLD_CONTENT}"
+                done
+            fi
+        fi
+        # Fresh install: init-system-specific setup
+        if [ "${INIT_SYSTEM}" = "systemd" ]; then
+            systemd-sysusers  || true
+            systemd-tmpfiles --create  || true
+            systemctl daemon-reload  || true
+        else
+            # runit: create group, set directory permissions
+            groupadd -f fenris
+            install -d -o root -g fenris -m 2750 "${STORE_DIR}" 2>/dev/null || true
+            # Mark runit service as dormant (down) for fresh install
+            if [ -d /etc/sv/fenris-collect ] && [ ! -e /var/service/fenris-collect ]; then
+                touch /etc/sv/fenris-collect/down
+            fi
+            # Ensure log directory exists
+            mkdir -p /var/log/fenris-collect
+            chown fenris:fenris /var/log/fenris-collect 2>/dev/null || true
         fi
-        # sysusers, tmpfiles, daemon-reload (both fresh install and upgrade)
-        systemd-sysusers  || true
-        systemd-tmpfiles --create  || true
-        systemctl daemon-reload  || true
         ;;
     abort-upgrade|abort-install|disappear)
         ;;

packaging/postrm.sh

@@ -5,6 +5,13 @@
 #             postrm purge     (after conffiles and config removed)
 set -eu
 
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
 case "${1:-}" in
     purge)
         rm -rf /etc/fenris
@@ -16,4 +23,10 @@ case "${1:-}" in
     remove|upgrade|failed-upgrade|abort-install|abort-upgrade|disappear)
         ;;
 esac
-systemctl daemon-reload 2>/dev/null || true
+if [ "${INIT_SYSTEM}" = "systemd" ]; then
+    systemctl daemon-reload 2>/dev/null || true
+else
+    # runit: clean up service directory and log
+    rm -rf /etc/sv/fenris-collect 2>/dev/null || true
+    rm -rf /var/log/fenris-collect 2>/dev/null || true
+fi

packaging/prerm.sh

@@ -5,14 +5,27 @@
 #             prerm upgrade  (old version about to be replaced)
 set -eu
 
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
 case "${1:-}" in
     remove)
         # Sanctioned disable — close monitoring period (spec §7)
         if [ -x /usr/libexec/fenris/fenris-monitor ]; then
             /usr/libexec/fenris/fenris-monitor disable --now 2>/dev/null || true
         fi
-        systemctl stop fenris-collect.timer 2>/dev/null || true
-        systemctl disable fenris-collect.timer 2>/dev/null || true
+        if [ "${INIT_SYSTEM}" = "systemd" ]; then
+            systemctl stop fenris-collect.timer 2>/dev/null || true
+            systemctl disable fenris-collect.timer 2>/dev/null || true
+        else
+            # runit: remove the service symlink
+            rm -f /var/service/fenris-collect
+            touch /etc/sv/fenris-collect/down 2>/dev/null || true
+        fi
         ;;
     upgrade)
         # Never interrupt monitoring on upgrade

packaging/rpm/post.sh

@@ -8,13 +8,33 @@ STORE_BAK="${STORE_DIR}/observations.db.bak"
 RUNTIME_PYTHON="/usr/bin/python3"
 VENDOR_DIR="/opt/fenris/vendor"
 
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
 if [ "$1" -eq 1 ]; then
     # Fresh install
-    systemd-sysusers  || true
-    systemd-tmpfiles --create  || true
-    systemctl daemon-reload  || true
+    if [ "${INIT_SYSTEM}" = "systemd" ]; then
+        systemd-sysusers  || true
+        systemd-tmpfiles --create  || true
+        systemctl daemon-reload  || true
+    else
+        # runit: create group, set directory permissions
+        groupadd -f fenris
+        install -d -o root -g fenris -m 2750 "${STORE_DIR}" 2>/dev/null || true
+        # Mark runit service as dormant (down) for fresh install
+        if [ -d /etc/sv/fenris-collect ] && [ ! -e /var/service/fenris-collect ]; then
+            touch /etc/sv/fenris-collect/down
+        fi
+        # Ensure log directory exists
+        mkdir -p /var/log/fenris-collect
+        chown fenris:fenris /var/log/fenris-collect 2>/dev/null || true
+    fi
 elif [ "$1" -ge 2 ]; then
-    # Upgrade — snapshot, migration, daemon-reload, conditional timer restart
+    # Upgrade — snapshot, migration, init-system-aware reload
     if [ -f "${STORE_DB}" ]; then
         cp "${STORE_DB}" "${STORE_BAK}" 2>/dev/null || true
     fi
@@ -26,24 +46,26 @@ n = migrate_to_latest(Path('${STORE_DB}'))
 print(f'Fenris migration: {n} step(s) applied') if n else None
 " 2>&1 || echo "Fenris: migration skipped (store not yet initialized)"
     fi
-    # Capture running unit content BEFORE daemon-reload (spec §7)
-    RUNNING_UNITS=""
-    for unit in fenris-collect.timer; do
-        if systemctl is-active --quiet "${unit}" 2>/dev/null; then
-            RUNNING_UNITS="${RUNNING_UNITS} ${unit}"
-        fi
-    done
-    systemctl daemon-reload 2>/dev/null || true
-    # Restart timer only if unit contents changed AND active
-    for unit in ${RUNNING_UNITS}; do
-        OLD_CONTENT="$(mktemp)"
-        NEW_PATH="/usr/lib/systemd/system/${unit}"
-        systemctl cat "${unit}" > "${OLD_CONTENT}" 2>/dev/null || true
-        if ! diff -q "${OLD_CONTENT}" "${NEW_PATH}" > /dev/null 2>&1; then
-            systemctl restart "${unit}" 2>/dev/null || true
-        fi
-        rm -f "${OLD_CONTENT}"
-    done
-    # Re-apply placement modes (store dir group access, issue #54)
-    systemd-tmpfiles --create  || true
+    if [ "${INIT_SYSTEM}" = "systemd" ]; then
+        # Capture running unit content BEFORE daemon-reload (spec §7)
+        RUNNING_UNITS=""
+        for unit in fenris-collect.timer; do
+            if systemctl is-active --quiet "${unit}" 2>/dev/null; then
+                RUNNING_UNITS="${RUNNING_UNITS} ${unit}"
+            fi
+        done
+        systemctl daemon-reload 2>/dev/null || true
+        # Restart timer only if unit contents changed AND active
+        for unit in ${RUNNING_UNITS}; do
+            OLD_CONTENT="$(mktemp)"
+            NEW_PATH="/usr/lib/systemd/system/${unit}"
+            systemctl cat "${unit}" > "${OLD_CONTENT}" 2>/dev/null || true
+            if ! diff -q "${OLD_CONTENT}" "${NEW_PATH}" > /dev/null 2>&1; then
+                systemctl restart "${unit}" 2>/dev/null || true
+            fi
+            rm -f "${OLD_CONTENT}"
+        done
+        # Re-apply placement modes (store dir group access, issue #54)
+        systemd-tmpfiles --create  || true
+    fi
 fi

packaging/rpm/postun.sh

@@ -2,6 +2,13 @@
 # RPM %postun — post-uninstall scriptlet (spec §7).
 set -eu
 
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
 if [ "$1" -eq 0 ]; then
     # Package fully erased — remove config, store, group
     rm -rf /etc/fenris
@@ -10,4 +17,10 @@ if [ "$1" -eq 0 ]; then
         groupdel fenris 2>/dev/null || true
     fi
 fi
-systemctl daemon-reload 2>/dev/null || true
+if [ "${INIT_SYSTEM}" = "systemd" ]; then
+    systemctl daemon-reload 2>/dev/null || true
+else
+    # runit: clean up service directory and log
+    rm -rf /etc/sv/fenris-collect 2>/dev/null || true
+    rm -rf /var/log/fenris-collect 2>/dev/null || true
+fi

packaging/rpm/preun.sh

@@ -2,12 +2,25 @@
 # RPM %preun — pre-uninstall scriptlet (spec §7).
 set -eu
 
+# Detect init system
+if [ -d /run/systemd/system ] || [ "$(cat /proc/1/comm 2>/dev/null)" = "systemd" ]; then
+    INIT_SYSTEM="systemd"
+else
+    INIT_SYSTEM="runit"
+fi
+
 if [ "$1" -eq 0 ]; then
     # Package is being erased — sanctioned disable (spec §7)
     if [ -x /usr/libexec/fenris/fenris-monitor ]; then
         /usr/libexec/fenris/fenris-monitor disable --now 2>/dev/null || true
     fi
-    systemctl stop fenris-collect.timer 2>/dev/null || true
-    systemctl disable fenris-collect.timer 2>/dev/null || true
+    if [ "${INIT_SYSTEM}" = "systemd" ]; then
+        systemctl stop fenris-collect.timer 2>/dev/null || true
+        systemctl disable fenris-collect.timer 2>/dev/null || true
+    else
+        # runit: remove the service symlink
+        rm -f /var/service/fenris-collect
+        touch /etc/sv/fenris-collect/down 2>/dev/null || true
+    fi
 fi
 # On upgrade ($1 -ge 1): do nothing

packaging/stage.sh

@@ -74,6 +74,12 @@ mkdir -p "${STAGE_DIR}/usr/lib/systemd/system"
 install -m 0644 "${REPO_ROOT}/units/fenris-collect.timer"   "${STAGE_DIR}/usr/lib/systemd/system/"
 install -m 0644 "${REPO_ROOT}/units/fenris-collect.service" "${STAGE_DIR}/usr/lib/systemd/system/"
 
+# --- runit service files ---
+echo "  Installing runit service files ..."
+mkdir -p "${STAGE_DIR}/etc/sv/fenris-collect/log"
+install -m 0755 "${REPO_ROOT}/units/runit/fenris-collect/run"     "${STAGE_DIR}/etc/sv/fenris-collect/run"
+install -m 0755 "${REPO_ROOT}/units/runit/fenris-collect/log/run" "${STAGE_DIR}/etc/sv/fenris-collect/log/run"
+
 # --- polkit policy ---
 echo "  Installing polkit policy ..."
 mkdir -p "${STAGE_DIR}/usr/share/polkit-1/actions"

src/fenris/init_system.py

@@ -0,0 +1,479 @@
+"""Init system abstraction for Fenris monitoring (issue #84).
+
+Detects the active init system (systemd or runit) and provides a unified
+interface for timer/collection control and service-state queries.  This keeps
+the privileged helper and status composition init-system agnostic without
+introducing a generalized plugin framework.
+
+Design: ADR 0008 — keep service-specific operations behind a cohesive
+responsibility shared by the privileged control path and read-only status
+composition.
+
+Runit service layout:
+  /etc/sv/fenris-collect/run        — scheduler (sleep 120; loop { collect; sleep 300 })
+  /etc/sv/fenris-collect/log/run    — logger to /var/log/fenris-collect/
+  /var/service/fenris-collect       — symlink to enable
+  /etc/sv/fenris-collect/down       — marker for dormant install
+
+Runit guarantees:
+  - Completion-relative 5-minute cadence (sleep 300 after each collect)
+  - Initial 2-minute boot delay (sleep 120 before first collect)
+  - Bounded execution (90s timeout via timeout(1))
+  - No catch-up (service sleeps fixed interval, no Persistent= flag)
+  - Serialized scheduled runs (runsv does not restart until exit)
+  - Serialized on-demand (flock serializes fenris-collect execution)
+
+Spec: §8.4, §8.5, §8.6, §8.7, §8.8, ADR 0008
+"""
+import os
+import shutil
+import subprocess
+import sys
+from enum import Enum
+from pathlib import Path
+from typing import Any, Dict, Optional
+
+
+# ---------------------------------------------------------------------------
+# Init system detection
+# ---------------------------------------------------------------------------
+
+class InitSystem(Enum):
+    SYSTEMD = "systemd"
+    RUNIT = "runit"
+
+
+FENRIS_SV_DIR = Path("/etc/sv/fenris-collect")
+FENRIS_SERVICE_LINK = Path("/var/service/fenris-collect")
+FENRIS_LOG_DIR = Path("/var/log/fenris-collect")
+COLLECT_TIMEOUT_S = 90
+
+
+def detect_init_system() -> InitSystem:
+    """Detect the active init system.
+
+    Checks for systemd first (PID 1 is systemd or /run/systemd/system exists),
+    then falls back to runit (PID 1 is runsv or /etc/sv exists).
+    """
+    # systemd detection: /run/systemd/system exists when systemd is PID 1
+    if Path("/run/systemd/system").exists():
+        return InitSystem.SYSTEMD
+
+    # Check PID 1 name
+    try:
+        pid1_comm = Path("/proc/1/comm").read_text().strip()
+        if pid1_comm == "systemd":
+            return InitSystem.SYSTEMD
+        if pid1_comm in ("runsv", "runsvdir"):
+            return InitSystem.RUNIT
+    except OSError:
+        pass
+
+    # Fallback: check for /etc/sv (Void Linux default)
+    if Path("/etc/sv").is_dir():
+        return InitSystem.RUNIT
+
+    # Default to systemd (existing behavior)
+    return InitSystem.SYSTEMD
+
+
+def get_init_system() -> InitSystem:
+    """Get the detected init system (cached)."""
+    if not hasattr(get_init_system, "_cached"):
+        get_init_system._cached = detect_init_system()
+    return get_init_system._cached
+
+
+def reset_init_system_cache() -> None:
+    """Reset the cached init system detection (for testing)."""
+    if hasattr(get_init_system, "_cached"):
+        delattr(get_init_system, "_cached")
+
+
+# ---------------------------------------------------------------------------
+# systemd backend
+# ---------------------------------------------------------------------------
+
+def _systemd_enable(now: bool) -> None:
+    """Enable and optionally start the systemd timer."""
+    cmd = ["systemctl", "enable"]
+    if now:
+        cmd.append("--now")
+    cmd.append("fenris-collect.timer")
+    result = subprocess.run(cmd, capture_output=True, text=True)
+    if result.returncode != 0:
+        print("Error enabling timer:", result.stderr, file=sys.stderr)
+        sys.exit(1)
+    print("Timer enabled" + (" and started" if now else ""))
+
+
+def _systemd_disable(now: bool) -> None:
+    """Disable and optionally stop the systemd timer."""
+    cmd = ["systemctl", "disable"]
+    if now:
+        cmd.append("--now")
+    cmd.append("fenris-collect.timer")
+    result = subprocess.run(cmd, capture_output=True, text=True)
+    if result.returncode != 0:
+        print("Error disabling timer:", result.stderr, file=sys.stderr)
+        sys.exit(1)
+    print("Timer disabled" + (" and stopped" if now else ""))
+
+
+def _systemd_collect() -> None:
+    """Trigger on-demand collection via systemd (blocking)."""
+    result = subprocess.run(
+        ["systemctl", "start", "fenris-collect.service"],
+        capture_output=True,
+        text=True,
+    )
+    if result.returncode == 0:
+        print("Collection completed successfully")
+    else:
+        print("Collection failed:", result.stderr, file=sys.stderr)
+        sys.exit(1)
+
+
+def _systemctl_show(unit: str, *properties: str) -> Dict[str, str]:
+    """Query systemctl show for specific properties."""
+    try:
+        result = subprocess.run(
+            ["systemctl", "show", unit, "--property=" + ",".join(properties)],
+            capture_output=True, text=True, timeout=5,
+        )
+        if result.returncode != 0:
+            return {}
+        out = {}
+        for line in result.stdout.splitlines():
+            if "=" in line:
+                key, _, value = line.partition("=")
+                out[key.strip()] = value.strip()
+        return out
+    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
+        return {}
+
+
+def _systemd_query_state() -> Dict[str, Any]:
+    """Query systemd for the four separate service facts."""
+    from datetime import datetime, timezone
+
+    timer_props = _systemctl_show(
+        "fenris-collect.timer",
+        "UnitFileState", "ActiveState", "LastTriggerUSec",
+    )
+    service_props = _systemctl_show(
+        "fenris-collect.service",
+        "ActiveState", "ExecMainStatus", "ExecMainExitTimestamp",
+    )
+
+    boot_enabled_str = timer_props.get("UnitFileState", "")
+    boot_enabled = boot_enabled_str == "enabled"
+
+    active_state = timer_props.get("ActiveState", "inactive")
+    timer_active = active_state == "active"
+
+    last_collect_ok = None
+    last_collect_age_s = None
+    last_collect_reason = None
+
+    last_trigger = timer_props.get("LastTriggerUSec", "")
+    if last_trigger and last_trigger != "n/a":
+        try:
+            trigger_dt = datetime.fromisoformat(last_trigger.replace("Z", "+00:00"))
+            now = datetime.now(timezone.utc)
+            last_collect_age_s = int((now - trigger_dt).total_seconds())
+        except (ValueError, TypeError):
+            pass
+
+    exec_status = service_props.get("ExecMainStatus", "")
+    if exec_status:
+        try:
+            exit_code = int(exec_status)
+            last_collect_ok = exit_code == 0
+            if exit_code != 0:
+                last_collect_reason = "exit code %d" % exit_code
+        except (ValueError, TypeError):
+            pass
+
+    return {
+        "boot_enabled": boot_enabled,
+        "timer_active": timer_active,
+        "last_collect_ok": last_collect_ok,
+        "last_collect_age_s": last_collect_age_s,
+        "last_collect_reason": last_collect_reason,
+    }
+
+
+def _systemd_journal_hint(lines: int = 5) -> Optional[str]:
+    """Get the last N journal lines for fenris-collect.service."""
+    try:
+        result = subprocess.run(
+            ["journalctl", "-u", "fenris-collect.service",
+             "--no-pager", "-n", str(lines), "--output=short-iso"],
+            capture_output=True, text=True, timeout=5,
+        )
+        if result.returncode != 0 or not result.stdout.strip():
+            return None
+        return result.stdout.strip()
+    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
+        return None
+
+
+# ---------------------------------------------------------------------------
+# runit backend
+# ---------------------------------------------------------------------------
+
+def _runit_enable(_now: bool) -> None:
+    """Enable the runit service by creating a symlink.
+
+    runit activates the service immediately when the symlink appears.
+    If the service is already enabled but stopped (e.g., via `sv stop`),
+    restart it when `now=True`.
+    """
+    if FENRIS_SERVICE_LINK.exists():
+        # Already enabled — check if we need to restart
+        if _now and not _runit_is_running():
+            # Service is stopped but enabled — restart via sv
+            try:
+                subprocess.run(
+                    ["sv", "restart", "fenris-collect"],
+                    capture_output=True, text=True, timeout=5,
+                )
+            except (FileNotFoundError, subprocess.TimeoutExpired):
+                pass
+        print("Service already enabled (idempotent)")
+        return
+
+    # Remove the 'down' file if present (dormant install marker)
+    down_file = FENRIS_SV_DIR / "down"
+    if down_file.exists():
+        down_file.unlink()
+
+    FENRIS_SERVICE_LINK.symlink_to(FENRIS_SV_DIR)
+    print("Service enabled")
+
+
+def _runit_disable(_now: bool) -> None:
+    """Disable the runit service by removing the symlink.
+
+    runit stops the service immediately when the symlink is removed.
+    """
+    if not FENRIS_SERVICE_LINK.exists():
+        print("Service already disabled (idempotent)")
+        return
+
+    FENRIS_SERVICE_LINK.unlink()
+    # Place 'down' file to mark as intentionally disabled
+    (FENRIS_SV_DIR / "down").touch()
+    print("Service disabled")
+
+
+def _runit_collect() -> None:
+    """Trigger on-demand collection via direct execution with flock.
+
+    Serializes against the scheduler using the same lock file.
+    The timeout(1) command enforces bounded execution.
+    """
+    lock_path = Path("/var/lib/fenris/fenris-collect.lock")
+    collect_script = Path("/usr/libexec/fenris/fenris-collect")
+    fallback_script = Path(__file__).parent.parent.parent / "src" / "fenris" / "collect.py"
+
+    if collect_script.exists():
+        script = str(collect_script)
+    elif fallback_script.exists():
+        script = str(fallback_script)
+    else:
+        print("Error: fenris-collect script not found", file=sys.stderr)
+        sys.exit(1)
+
+    try:
+        result = subprocess.run(
+            ["flock", "--nonblock", str(lock_path),
+             "timeout", str(COLLECT_TIMEOUT_S), "nice", "ionice", "-c3",
+             sys.executable, script],
+            capture_output=True,
+            text=True,
+        )
+        if result.returncode == 0:
+            print("Collection completed successfully")
+        elif result.returncode == 124:
+            print("Collection timed out after %ds" % COLLECT_TIMEOUT_S, file=sys.stderr)
+            sys.exit(1)
+        else:
+            # exit code 1 from flock means lock is held (scheduled run in progress)
+            if result.returncode == 1 and "Resource temporarily unavailable" in result.stderr:
+                print("Collection already in progress (serialized)", file=sys.stderr)
+                sys.exit(1)
+            print("Collection failed:", result.stderr, file=sys.stderr)
+            sys.exit(1)
+    except FileNotFoundError:
+        print("Error: flock/timeout not found", file=sys.stderr)
+        sys.exit(1)
+
+
+def _runit_is_enabled() -> bool:
+    """Check if the runit service is enabled (symlink exists)."""
+    return FENRIS_SERVICE_LINK.exists()
+
+
+def _runit_is_running() -> bool:
+    """Check if the runit service is currently running.
+
+    Looks for a 'supervise/pid' file in the service directory.
+    """
+    pid_file = FENRIS_SV_DIR / "supervise" / "pid"
+    if not pid_file.exists():
+        return False
+    try:
+        pid = int(pid_file.read_text().strip())
+        # Check if the process is alive
+        os.kill(pid, 0)
+        return True
+    except (ValueError, OSError):
+        return False
+
+
+def _runit_query_state() -> Dict[str, Any]:
+    """Query runit for the four separate service facts.
+
+    Checks: boot_enabled (symlink), timer_active (running), last_collect
+    (store-based), freshness (store-based).
+    """
+    from datetime import datetime, timezone
+    from pathlib import Path
+
+    boot_enabled = _runit_is_enabled()
+    timer_active = _runit_is_running()
+
+    last_collect_ok = None
+    last_collect_age_s = None
+    last_collect_reason = None
+
+    # Try to get last collection info from the store
+    store_path = Path("/var/lib/fenris/observations.db")
+    if store_path.exists():
+        try:
+            import sqlite3
+            conn = sqlite3.connect("file:%s?mode=ro" % store_path, uri=True)
+            conn.row_factory = sqlite3.Row
+
+            # Get newest sample
+            cursor = conn.execute(
+                "SELECT ts FROM samples ORDER BY id DESC LIMIT 1"
+            )
+            row = cursor.fetchone()
+            if row and row[0]:
+                try:
+                    ts = datetime.fromisoformat(row[0])
+                    if ts.tzinfo is None:
+                        ts = ts.replace(tzinfo=timezone.utc)
+                    now = datetime.now(timezone.utc)
+                    last_collect_age_s = int((now - ts).total_seconds())
+                    last_collect_ok = True
+                except (ValueError, TypeError):
+                    pass
+
+            # Check for failed collections via monitoring_periods
+            cursor = conn.execute(
+                "SELECT end_cause FROM monitoring_periods "
+                "WHERE ended_at IS NOT NULL ORDER BY ended_at DESC LIMIT 1"
+            )
+            row = cursor.fetchone()
+            if row and row[0] and row[0] not in ("user_disabled", None):
+                last_collect_reason = row[0]
+
+            conn.close()
+        except Exception:
+            pass
+
+    # Check for timeout/exit failures via supervise exit status
+    if timer_active:
+        exit_file = FENRIS_SV_DIR / "supervise" / "exit"
+        if exit_file.exists():
+            try:
+                exit_code = int(exit_file.read_text().strip())
+                if exit_code != 0:
+                    last_collect_ok = False
+                    last_collect_reason = "exit code %d" % exit_code
+            except (ValueError, OSError):
+                pass
+
+    return {
+        "boot_enabled": boot_enabled,
+        "timer_active": timer_active,
+        "last_collect_ok": last_collect_ok,
+        "last_collect_age_s": last_collect_age_s,
+        "last_collect_reason": last_collect_reason,
+    }
+
+
+def _runit_journal_hint(lines: int = 5) -> Optional[str]:
+    """Get the last N log lines for fenris-collect from runit logging."""
+    log_current = FENRIS_LOG_DIR / "current"
+    if not log_current.exists():
+        return None
+    try:
+        # Use tail to get the last N lines
+        result = subprocess.run(
+            ["tail", "-n", str(lines), str(log_current)],
+            capture_output=True, text=True, timeout=5,
+        )
+        if result.returncode != 0 or not result.stdout.strip():
+            return None
+        return result.stdout.strip()
+    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
+        return None
+
+
+# ---------------------------------------------------------------------------
+# Public API — unified interface
+# ---------------------------------------------------------------------------
+
+def enable_timer(now: bool) -> None:
+    """Enable the collection timer/service."""
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        _systemd_enable(now)
+    else:
+        _runit_enable(now)
+
+
+def disable_timer(now: bool) -> None:
+    """Disable the collection timer/service."""
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        _systemd_disable(now)
+    else:
+        _runit_disable(now)
+
+
+def collect_now() -> None:
+    """Trigger on-demand collection (blocking)."""
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        _systemd_collect()
+    else:
+        _runit_collect()
+
+
+def query_service_state() -> Dict[str, Any]:
+    """Query the four separate service facts."""
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        return _systemd_query_state()
+    else:
+        return _runit_query_state()
+
+
+def journal_hint(lines: int = 5, unit: str = "fenris-collect.service") -> Optional[str]:
+    """Get journal/log hints for diagnostics.
+
+    The unit parameter is accepted for backward compatibility with callers
+    that pass 'fenris-collect.service'.  For runit, the unit parameter is
+    ignored since the log directory is always /var/log/fenris-collect/.
+    """
+    init = get_init_system()
+    if init == InitSystem.SYSTEMD:
+        return _systemd_journal_hint(lines)
+    else:
+        return _runit_journal_hint(lines)

src/fenris/monitor.py

@@ -15,9 +15,7 @@ When run as a script, uses the fenris package from the installed wheel.
 import argparse
 import json
 import os
-import subprocess
 import sys
-import sqlite3
 from datetime import datetime, timezone
 from pathlib import Path
 
@@ -39,6 +37,11 @@ from fenris.monitoring_periods import (
     close_period,
     get_open_period,
 )
+from fenris.init_system import (
+    enable_timer,
+    disable_timer,
+    collect_now,
+)
 
 
 DEFAULT_STORE_PATH = Path("/var/lib/fenris/observations.db")
@@ -70,25 +73,8 @@ def cmd_enable(args: argparse.Namespace) -> None:
         else:
             print("Monitoring period already open (id=%d)" % open_period["id"])
 
-        # Enable and start the timer
-        if args.now:
-            result = subprocess.run(
-                ["systemctl", "enable", "--now", "fenris-collect.timer"],
-                capture_output=True,
-                text=True,
-            )
-        else:
-            result = subprocess.run(
-                ["systemctl", "enable", "fenris-collect.timer"],
-                capture_output=True,
-                text=True,
-            )
-
-        if result.returncode != 0:
-            print("Error enabling timer:", result.stderr, file=sys.stderr)
-            sys.exit(1)
-
-        print("Timer enabled" + (" and started" if args.now else ""))
+        # Enable the timer (init-system aware)
+        enable_timer(args.now)
     finally:
         conn.close()
 
@@ -117,25 +103,8 @@ def cmd_disable(args: argparse.Namespace) -> None:
         else:
             print("No open monitoring period (no-op)")
 
-        # Disable and stop the timer
-        if args.now:
-            result = subprocess.run(
-                ["systemctl", "disable", "--now", "fenris-collect.timer"],
-                capture_output=True,
-                text=True,
-            )
-        else:
-            result = subprocess.run(
-                ["systemctl", "disable", "fenris-collect.timer"],
-                capture_output=True,
-                text=True,
-            )
-
-        if result.returncode != 0:
-            print("Error disabling timer:", result.stderr, file=sys.stderr)
-            sys.exit(1)
-
-        print("Timer disabled" + (" and stopped" if args.now else ""))
+        # Disable the timer (init-system aware)
+        disable_timer(args.now)
     finally:
         conn.close()
 
@@ -143,22 +112,12 @@ def cmd_disable(args: argparse.Namespace) -> None:
 def cmd_collect(args: argparse.Namespace) -> None:
     """Trigger on-demand collection.
 
-    Starts fenris-collect.service, blocks until exit, reports outcome.
+    Starts fenris-collect, blocks until exit, reports outcome.
 
-    Spec §8.7: fenris sample routes through fenris-monitor → systemctl start,
-    which blocks until the oneshot exits; outcome reported synchronously.
+    Spec §8.7: fenris sample routes through fenris-monitor → collect,
+    which blocks until the collection exits; outcome reported synchronously.
     """
-    result = subprocess.run(
-        ["systemctl", "start", "fenris-collect.service"],
-        capture_output=True,
-        text=True,
-    )
-
-    if result.returncode == 0:
-        print("Collection completed successfully")
-    else:
-        print("Collection failed:", result.stderr, file=sys.stderr)
-        sys.exit(1)
+    collect_now()
 
 
 def cmd_baseline_set(args: argparse.Namespace) -> None:

src/fenris/status.py

@@ -1,8 +1,8 @@
 """Read-only CLI status command: the CLI twin of the TUI (spec §8.8, LC-9, CI-2).
 
-Composes from the observation store (read-only) and allow-listed systemctl
+Composes from the observation store (read-only) and allow-listed service
 properties: projection facts, four separate service facts (boot enablement,
-runtime activity, last collect outcome, freshness), and a journalctl hint on
+runtime activity, last collect outcome, freshness), and a journal/log hint on
 failure or staleness.  Never auto-samples, never prompts.
 
 Freshness constants are defined once here and shared with the TUI (§8.9):
@@ -14,7 +14,6 @@ Freshness constants are defined once here and shared with the TUI (§8.9):
 Criteria: LC-9, CI-2, CI-4, FL-4, FL-5, FL-7.
 """
 import sqlite3
-import subprocess
 import sys
 from datetime import datetime, timedelta, timezone
 from pathlib import Path
@@ -22,6 +21,10 @@ from typing import Any, Dict, List, Optional, Tuple
 
 from .projection import compute_projection, ConfidenceState, DISCLOSURES
 from .store import SCHEMA_VERSION
+from .init_system import (
+    query_service_state as _init_query_service_state,
+    journal_hint as _init_journal_hint,
+)
 
 
 # ---------------------------------------------------------------------------
@@ -130,97 +133,12 @@ class NewerSchema(Exception):
 
 
 # ---------------------------------------------------------------------------
-# Service state queries (§8.8 — allow-listed systemctl properties)
+# Service state queries (§8.8 — init-system agnostic)
 # ---------------------------------------------------------------------------
 
-def _systemctl_show(unit: str, *properties: str) -> Dict[str, str]:
-    """Query systemctl show for specific properties.  Returns empty dict on failure."""
-    try:
-        result = subprocess.run(
-            ["systemctl", "show", unit, "--property=" + ",".join(properties)],
-            capture_output=True, text=True, timeout=5,
-        )
-        if result.returncode != 0:
-            return {}
-        out = {}
-        for line in result.stdout.splitlines():
-            if "=" in line:
-                key, _, value = line.partition("=")
-                out[key.strip()] = value.strip()
-        return out
-    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
-        return {}
-
-
-def _journalctl_hint(unit: str, lines: int = 5) -> Optional[str]:
-    """Get the last N journal lines for a unit.  Returns None on failure."""
-    try:
-        result = subprocess.run(
-            ["journalctl", "-u", unit, "--no-pager", "-n", str(lines), "--output=short-iso"],
-            capture_output=True, text=True, timeout=5,
-        )
-        if result.returncode != 0 or not result.stdout.strip():
-            return None
-        return result.stdout.strip()
-    except (subprocess.TimeoutExpired, FileNotFoundError, OSError):
-        return None
-
-
-def query_service_state() -> Dict[str, Any]:
-    """Query systemctl for the four separate service facts (§7.3, LC-9).
-
-    Returns dict with keys:
-      boot_enabled: bool
-      timer_active: bool
-      last_collect_ok: Optional[bool]
-      last_collect_age_s: Optional[int]
-      last_collect_reason: Optional[str]
-    """
-    timer_props = _systemctl_show(
-        "fenris-collect.timer",
-        "UnitFileState", "ActiveState", "LastTriggerUSec",
-    )
-    service_props = _systemctl_show(
-        "fenris-collect.service",
-        "ActiveState", "ExecMainStatus", "ExecMainExitTimestamp",
-    )
-
-    boot_enabled_str = timer_props.get("UnitFileState", "")
-    boot_enabled = boot_enabled_str == "enabled"
-
-    active_state = timer_props.get("ActiveState", "inactive")
-    timer_active = active_state == "active"
-
-    last_collect_ok = None
-    last_collect_age_s = None
-    last_collect_reason = None
-
-    last_trigger = timer_props.get("LastTriggerUSec", "")
-    if last_trigger and last_trigger != "n/a":
-        try:
-            trigger_dt = datetime.fromisoformat(last_trigger.replace("Z", "+00:00"))
-            now = datetime.now(timezone.utc)
-            last_collect_age_s = int((now - trigger_dt).total_seconds())
-        except (ValueError, TypeError):
-            pass
-
-    exec_status = service_props.get("ExecMainStatus", "")
-    if exec_status:
-        try:
-            exit_code = int(exec_status)
-            last_collect_ok = exit_code == 0
-            if exit_code != 0:
-                last_collect_reason = "exit code %d" % exit_code
-        except (ValueError, TypeError):
-            pass
-
-    return {
-        "boot_enabled": boot_enabled,
-        "timer_active": timer_active,
-        "last_collect_ok": last_collect_ok,
-        "last_collect_age_s": last_collect_age_s,
-        "last_collect_reason": last_collect_reason,
-    }
+# Re-export for backward compatibility with tests that import directly
+query_service_state = _init_query_service_state
+_journalctl_hint = _init_journal_hint
 
 
 # ---------------------------------------------------------------------------
@@ -601,7 +519,7 @@ def get_status(store_path: Optional[Path] = None, clock_now: Optional[datetime]
     if store_fault or newer_schema:
         journal_hint = None
         if query_journal:
-            journal_hint = _journalctl_hint("fenris-collect.service")
+            journal_hint = _journalctl_hint()
         service["freshness"] = "unknown"
         service["freshness_age_s"] = None
         return _format_projection(
@@ -663,7 +581,7 @@ def get_status(store_path: Optional[Path] = None, clock_now: Optional[datetime]
     # --- Journal hint on failure or staleness (§8.8) ---
     journal_hint = None
     if query_journal and freshness in ("missed", "stale"):
-        journal_hint = _journalctl_hint("fenris-collect.service")
+        journal_hint = _journalctl_hint()
 
     # --- Compose output ---
     result = _format_projection(

tests/test_init_system.py

@@ -0,0 +1,659 @@
+"""Tests for the init system abstraction layer (issue #84).
+
+Covers:
+  - Init system detection (systemd vs runit)
+  - systemd backend functions (enable, disable, collect, query state)
+  - runit backend functions (enable, disable, collect, query state)
+  - Public API dispatching to correct backend
+  - Edge cases (already enabled/disabled, missing files, timeouts)
+
+Spec: ADR 0008, §8.4, §8.5, §8.6, §8.7, §8.8
+"""
+import os
+import sqlite3
+import tempfile
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+from unittest.mock import patch, MagicMock, PropertyMock
+
+import pytest
+
+import sys
+sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
+
+from fenris.init_system import (
+    InitSystem,
+    detect_init_system,
+    get_init_system,
+    reset_init_system_cache,
+    _systemd_enable,
+    _systemd_disable,
+    _systemd_collect,
+    _systemd_query_state,
+    _runit_enable,
+    _runit_disable,
+    _runit_collect,
+    _runit_query_state,
+    _runit_is_enabled,
+    _runit_is_running,
+    enable_timer,
+    disable_timer,
+    collect_now,
+    query_service_state,
+    journal_hint,
+    FENRIS_SV_DIR,
+    FENRIS_SERVICE_LINK,
+    COLLECT_TIMEOUT_S,
+)
+from fenris.store import init_store
+
+
+@pytest.fixture(autouse=True)
+def reset_cache():
+    """Reset the init system cache before each test."""
+    reset_init_system_cache()
+    yield
+    reset_init_system_cache()
+
+
+# ---------------------------------------------------------------------------
+# Init system detection
+# ---------------------------------------------------------------------------
+
+class TestInitSystemDetection:
+    """Test init system detection logic."""
+
+    def test_detect_systemd_by_run_directory(self):
+        """Systemd detected via /run/systemd/system directory."""
+        with patch("pathlib.Path.exists") as mock_exists:
+            mock_exists.return_value = True
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.SYSTEMD
+
+    def test_detect_systemd_by_pid1(self):
+        """Systemd detected via PID 1 name."""
+        original_exists = Path.exists
+        original_read_text = Path.read_text
+
+        def mock_exists(self_path):
+            if str(self_path) == "/run/systemd/system":
+                return False
+            return original_exists(self_path)
+
+        def mock_read_text(self_path):
+            if str(self_path) == "/proc/1/comm":
+                return "systemd"
+            return original_read_text(self_path)
+
+        with patch("pathlib.Path.exists", mock_exists), \
+             patch("pathlib.Path.read_text", mock_read_text):
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.SYSTEMD
+
+    def test_detect_runit_by_pid1(self):
+        """Runit detected via PID 1 name."""
+        original_exists = Path.exists
+        original_read_text = Path.read_text
+
+        def mock_exists(self_path):
+            if str(self_path) == "/run/systemd/system":
+                return False
+            return original_exists(self_path)
+
+        def mock_read_text(self_path):
+            if str(self_path) == "/proc/1/comm":
+                return "runsv"
+            return original_read_text(self_path)
+
+        with patch("pathlib.Path.exists", mock_exists), \
+             patch("pathlib.Path.read_text", mock_read_text):
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.RUNIT
+
+    def test_detect_runit_by_etc_sv(self):
+        """Runit detected via /etc/sv directory."""
+        original_exists = Path.exists
+        original_read_text = Path.read_text
+
+        def mock_exists(self_path):
+            if str(self_path) == "/run/systemd/system":
+                return False
+            if str(self_path) == "/etc/sv":
+                return True
+            return original_exists(self_path)
+
+        def mock_read_text(self_path):
+            if str(self_path) == "/proc/1/comm":
+                raise OSError("no such file")
+            return original_read_text(self_path)
+
+        with patch("pathlib.Path.exists", mock_exists), \
+             patch("pathlib.Path.read_text", mock_read_text):
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.RUNIT
+
+    def test_default_to_systemd(self):
+        """Default to systemd when no detection matches."""
+        original_exists = Path.exists
+        original_read_text = Path.read_text
+        original_is_dir = Path.is_dir
+
+        def mock_exists(self_path):
+            if str(self_path) == "/run/systemd/system":
+                return False
+            return original_exists(self_path)
+
+        def mock_is_dir(self_path):
+            if str(self_path) == "/etc/sv":
+                return False
+            return original_is_dir(self_path)
+
+        def mock_read_text(self_path):
+            if str(self_path) == "/proc/1/comm":
+                raise OSError("no such file")
+            return original_read_text(self_path)
+
+        with patch("pathlib.Path.exists", mock_exists), \
+             patch("pathlib.Path.is_dir", mock_is_dir), \
+             patch("pathlib.Path.read_text", mock_read_text):
+            reset_init_system_cache()
+            result = detect_init_system()
+            assert result == InitSystem.SYSTEMD
+
+
+# ---------------------------------------------------------------------------
+# systemd backend
+# ---------------------------------------------------------------------------
+
+class TestSystemdEnable:
+    """Test systemd enable function."""
+
+    def test_enable_now(self):
+        """Enable with --now flag."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_enable(now=True)
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "enable", "--now", "fenris-collect.timer"],
+                capture_output=True, text=True,
+            )
+
+    def test_enable_without_now(self):
+        """Enable without --now flag."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_enable(now=False)
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "enable", "fenris-collect.timer"],
+                capture_output=True, text=True,
+            )
+
+    def test_enable_failure_exits(self):
+        """Enable failure exits with error."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(
+                returncode=1, stderr="Unit not found"
+            )
+            with pytest.raises(SystemExit) as exc_info:
+                _systemd_enable(now=True)
+            assert exc_info.value.code == 1
+
+
+class TestSystemdDisable:
+    """Test systemd disable function."""
+
+    def test_disable_now(self):
+        """Disable with --now flag."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_disable(now=True)
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "disable", "--now", "fenris-collect.timer"],
+                capture_output=True, text=True,
+            )
+
+    def test_disable_without_now(self):
+        """Disable without --now flag."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_disable(now=False)
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "disable", "fenris-collect.timer"],
+                capture_output=True, text=True,
+            )
+
+
+class TestSystemdCollect:
+    """Test systemd collect function."""
+
+    def test_collect_success(self):
+        """Successful collection."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _systemd_collect()
+            mock_sub.run.assert_called_once_with(
+                ["systemctl", "start", "fenris-collect.service"],
+                capture_output=True, text=True,
+            )
+
+    def test_collect_failure_exits(self):
+        """Collection failure exits with error."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(
+                returncode=1, stderr="Unit not found"
+            )
+            with pytest.raises(SystemExit) as exc_info:
+                _systemd_collect()
+            assert exc_info.value.code == 1
+
+
+class TestSystemdQueryState:
+    """Test systemd query state function."""
+
+    def test_query_state_enabled_active(self):
+        """Query state for enabled and active timer."""
+        with patch("fenris.init_system._systemctl_show") as mock_show:
+            def mock_show_fn(unit, *props):
+                if unit == "fenris-collect.timer":
+                    return {
+                        "UnitFileState": "enabled",
+                        "ActiveState": "active",
+                        "LastTriggerUSec": "2026-09-01T12:00:00Z",
+                    }
+                elif unit == "fenris-collect.service":
+                    return {
+                        "ActiveState": "inactive",
+                        "ExecMainStatus": "0",
+                        "ExecMainExitTimestamp": "2026-09-01T12:00:30Z",
+                    }
+                return {}
+            mock_show.side_effect = mock_show_fn
+
+            result = _systemd_query_state()
+
+            assert result["boot_enabled"] is True
+            assert result["timer_active"] is True
+            assert result["last_collect_ok"] is True
+            assert result["last_collect_age_s"] is not None
+
+    def test_query_state_disabled_inactive(self):
+        """Query state for disabled and inactive timer."""
+        with patch("fenris.init_system._systemctl_show") as mock_show:
+            mock_show.return_value = {}
+            result = _systemd_query_state()
+            assert result["boot_enabled"] is False
+            assert result["timer_active"] is False
+            assert result["last_collect_ok"] is None
+
+
+# ---------------------------------------------------------------------------
+# runit backend
+# ---------------------------------------------------------------------------
+
+class TestRunitEnable:
+    """Test runit enable function."""
+
+    def test_enable_creates_symlink(self, tmp_path):
+        """Enable creates symlink to service directory."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_enable(_now=True)
+            assert service_link.exists()
+            assert service_link.is_symlink()
+            assert service_link.resolve() == sv_dir
+
+    def test_enable_removes_down_file(self, tmp_path):
+        """Enable removes the 'down' file if present."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        (sv_dir / "down").touch()
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_enable(_now=True)
+            assert not (sv_dir / "down").exists()
+
+    def test_enable_idempotent(self, tmp_path):
+        """Enable is idempotent when already enabled."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+        service_link.symlink_to(sv_dir)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_enable(_now=True)
+            assert service_link.exists()
+
+
+class TestRunitDisable:
+    """Test runit disable function."""
+
+    def test_disable_removes_symlink(self, tmp_path):
+        """Disable removes the service symlink."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+        service_link.symlink_to(sv_dir)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_disable(_now=True)
+            assert not service_link.exists()
+            assert (sv_dir / "down").exists()
+
+    def test_disable_idempotent(self, tmp_path):
+        """Disable is idempotent when already disabled."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            _runit_disable(_now=True)
+            assert not service_link.exists()
+
+
+class TestRunitCollect:
+    """Test runit collect function."""
+
+    def test_collect_uses_flock(self):
+        """Collect uses flock for serialization."""
+        with patch("fenris.init_system.subprocess") as mock_sub, \
+             patch("fenris.init_system.Path") as mock_path:
+            mock_path.return_value.exists.return_value = True
+            mock_sub.run.return_value = MagicMock(returncode=0)
+            _runit_collect()
+            # Verify flock was used
+            call_args = mock_sub.run.call_args[0][0]
+            assert "flock" in call_args
+
+    def test_collect_timeout_exits(self):
+        """Collection timeout exits with error."""
+        with patch("fenris.init_system.subprocess") as mock_sub, \
+             patch("fenris.init_system.Path") as mock_path:
+            mock_path.return_value.exists.return_value = True
+            mock_sub.run.return_value = MagicMock(returncode=124)
+            with pytest.raises(SystemExit) as exc_info:
+                _runit_collect()
+            assert exc_info.value.code == 1
+
+
+class TestRunitQueryState:
+    """Test runit query state function."""
+
+    def test_query_state_enabled_running(self, tmp_path):
+        """Query state for enabled and running service."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        supervise_dir = sv_dir / "supervise"
+        supervise_dir.mkdir(parents=True)
+        (supervise_dir / "pid").write_text("12345")
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+        service_link.symlink_to(sv_dir)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link), \
+             patch("os.kill") as mock_kill:
+            mock_kill.return_value = True  # Process exists
+            result = _runit_query_state()
+            assert result["boot_enabled"] is True
+            assert result["timer_active"] is True
+
+    def test_query_state_disabled_not_running(self, tmp_path):
+        """Query state for disabled and not running service."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            result = _runit_query_state()
+            assert result["boot_enabled"] is False
+            assert result["timer_active"] is False
+
+
+class TestRunitIsEnabled:
+    """Test runit is_enabled check."""
+
+    def test_is_enabled_true(self, tmp_path):
+        """Service is enabled when symlink exists."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+        service_link = tmp_path / "service" / "fenris-collect"
+        service_link.parent.mkdir(parents=True)
+        service_link.symlink_to(sv_dir)
+
+        with patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            assert _runit_is_enabled() is True
+
+    def test_is_enabled_false(self, tmp_path):
+        """Service is disabled when symlink does not exist."""
+        service_link = tmp_path / "service" / "fenris-collect"
+
+        with patch("fenris.init_system.FENRIS_SERVICE_LINK", service_link):
+            assert _runit_is_enabled() is False
+
+
+class TestRunitIsRunning:
+    """Test runit is_running check."""
+
+    def test_is_running_true(self, tmp_path):
+        """Service is running when PID file exists and process is alive."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        supervise_dir = sv_dir / "supervise"
+        supervise_dir.mkdir(parents=True)
+        (supervise_dir / "pid").write_text("12345")
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("os.kill") as mock_kill:
+            mock_kill.return_value = True
+            assert _runit_is_running() is True
+
+    def test_is_running_false_no_pid(self, tmp_path):
+        """Service is not running when PID file does not exist."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        sv_dir.mkdir(parents=True)
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir):
+            assert _runit_is_running() is False
+
+    def test_is_running_false_dead_process(self, tmp_path):
+        """Service is not running when process is dead."""
+        sv_dir = tmp_path / "sv" / "fenris-collect"
+        supervise_dir = sv_dir / "supervise"
+        supervise_dir.mkdir(parents=True)
+        (supervise_dir / "pid").write_text("12345")
+
+        with patch("fenris.init_system.FENRIS_SV_DIR", sv_dir), \
+             patch("os.kill", side_effect=OSError("No such process")):
+            assert _runit_is_running() is False
+
+
+# ---------------------------------------------------------------------------
+# Public API dispatching
+# ---------------------------------------------------------------------------
+
+class TestPublicAPI:
+    """Test public API dispatches to correct backend."""
+
+    def test_enable_dispatches_to_systemd(self):
+        """enable_timer dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_enable") as mock_enable:
+            enable_timer(now=True)
+            mock_enable.assert_called_once_with(True)
+
+    def test_enable_dispatches_to_runit(self):
+        """enable_timer dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_enable") as mock_enable:
+            enable_timer(now=True)
+            mock_enable.assert_called_once_with(True)
+
+    def test_disable_dispatches_to_systemd(self):
+        """disable_timer dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_disable") as mock_disable:
+            disable_timer(now=False)
+            mock_disable.assert_called_once_with(False)
+
+    def test_disable_dispatches_to_runit(self):
+        """disable_timer dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_disable") as mock_disable:
+            disable_timer(now=False)
+            mock_disable.assert_called_once_with(False)
+
+    def test_collect_dispatches_to_systemd(self):
+        """collect_now dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_collect") as mock_collect:
+            collect_now()
+            mock_collect.assert_called_once()
+
+    def test_collect_dispatches_to_runit(self):
+        """collect_now dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_collect") as mock_collect:
+            collect_now()
+            mock_collect.assert_called_once()
+
+    def test_query_state_dispatches_to_systemd(self):
+        """query_service_state dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_query_state") as mock_query:
+            query_service_state()
+            mock_query.assert_called_once()
+
+    def test_query_state_dispatches_to_runit(self):
+        """query_service_state dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_query_state") as mock_query:
+            query_service_state()
+            mock_query.assert_called_once()
+
+    def test_journal_hint_dispatches_to_systemd(self):
+        """journal_hint dispatches to systemd on systemd system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.SYSTEMD), \
+             patch("fenris.init_system._systemd_journal_hint") as mock_hint:
+            journal_hint(lines=3, unit="fenris-collect.service")
+            mock_hint.assert_called_once_with(3)
+
+    def test_journal_hint_dispatches_to_runit(self):
+        """journal_hint dispatches to runit on runit system."""
+        with patch("fenris.init_system.get_init_system", return_value=InitSystem.RUNIT), \
+             patch("fenris.init_system._runit_journal_hint") as mock_hint:
+            journal_hint(lines=3, unit="fenris-collect.service")
+            mock_hint.assert_called_once_with(3)
+
+
+# ---------------------------------------------------------------------------
+# Constants and configuration
+# ---------------------------------------------------------------------------
+
+class TestConstants:
+    """Test constants match spec requirements."""
+
+    def test_collect_timeout(self):
+        """Collection timeout is 90 seconds (bounded execution)."""
+        assert COLLECT_TIMEOUT_S == 90
+
+    def test_init_system_enum(self):
+        """InitSystem enum has systemd and runit variants."""
+        assert InitSystem.SYSTEMD.value == "systemd"
+        assert InitSystem.RUNIT.value == "runit"
+
+
+# ---------------------------------------------------------------------------
+# Integration with monitor.py
+# ---------------------------------------------------------------------------
+
+class TestMonitorIntegration:
+    """Test that monitor.py uses the abstraction layer correctly."""
+
+    def test_cmd_enable_uses_init_system(self, tmp_path):
+        """cmd_enable uses init_system.enable_timer."""
+        from fenris.monitor import cmd_enable
+        from argparse import Namespace
+
+        store_path = tmp_path / "observations.db"
+        init_store(store_path)
+        args = Namespace(now=True, store_path=store_path)
+
+        with patch("fenris.monitor.enable_timer") as mock_enable:
+            cmd_enable(args)
+            mock_enable.assert_called_once_with(True)
+
+    def test_cmd_disable_uses_init_system(self, tmp_path):
+        """cmd_disable uses init_system.disable_timer."""
+        from fenris.monitor import cmd_disable
+        from argparse import Namespace
+
+        store_path = tmp_path / "observations.db"
+        init_store(store_path)
+        args = Namespace(now=True, store_path=store_path)
+
+        with patch("fenris.monitor.disable_timer") as mock_disable:
+            cmd_disable(args)
+            mock_disable.assert_called_once_with(True)
+
+    def test_cmd_collect_uses_init_system(self):
+        """cmd_collect uses init_system.collect_now."""
+        from fenris.monitor import cmd_collect
+        from argparse import Namespace
+
+        args = Namespace()
+
+        with patch("fenris.monitor.collect_now") as mock_collect:
+            cmd_collect(args)
+            mock_collect.assert_called_once()
+
+
+# ---------------------------------------------------------------------------
+# Edge cases
+# ---------------------------------------------------------------------------
+
+class TestEdgeCases:
+    """Test edge cases and error handling."""
+
+    def test_systemd_enable_failure_produces_stderr(self):
+        """Systemd enable failure produces error message on stderr."""
+        with patch("fenris.init_system.subprocess") as mock_sub:
+            mock_sub.run.return_value = MagicMock(
+                returncode=1, stderr="Permission denied"
+            )
+            with pytest.raises(SystemExit):
+                _systemd_enable(now=True)
+
+    def test_runit_collect_missing_script(self):
+        """Runit collect exits when fenris-collect script not found."""
+        with patch("fenris.init_system.Path") as mock_path:
+            mock_path.return_value.exists.return_value = False
+            with pytest.raises(SystemExit) as exc_info:
+                _runit_collect()
+            assert exc_info.value.code == 1
+
+    def test_systemd_query_state_timeout(self):
+        """Systemd query state handles subprocess timeout."""
+        with patch("fenris.init_system._systemctl_show") as mock_show:
+            mock_show.return_value = {}
+            result = _systemd_query_state()
+            assert result["boot_enabled"] is False
+            assert result["timer_active"] is False

tests/test_monitor.py

@@ -56,8 +56,7 @@ class TestEnableIdempotentMatrix:
         """A fresh package install has a store directory but no database yet."""
         args = MagicMock(now=False, store_path=store_path)
 
-        with patch("fenris.monitor.subprocess") as mock_sub:
-            mock_sub.run.return_value = MagicMock(returncode=0)
+        with patch("fenris.monitor.enable_timer") as mock_enable:
             cmd_enable(args)
 
         conn = init_store(store_path)
@@ -74,8 +73,7 @@ class TestEnableIdempotentMatrix:
         
         args = MagicMock(now=False, store_path=store_path)
 
-        with patch("fenris.monitor.subprocess") as mock_sub:
-            mock_sub.run.return_value = MagicMock(returncode=0)
+        with patch("fenris.monitor.enable_timer") as mock_enable:
             cmd_enable(args)
 
         # Period should be open
@@ -100,8 +98,7 @@ class TestEnableIdempotentMatrix:
 
         args = MagicMock(now=True, store_path=store_path)
 
-        with patch("fenris.monitor.subprocess") as mock_sub:
-            mock_sub.run.return_value = MagicMock(returncode=0)
+        with patch("fenris.monitor.enable_timer") as mock_enable:
             cmd_enable(args)
 
         # Should still have exactly one open period
@@ -125,8 +122,7 @@ class TestEnableIdempotentMatrix:
 
         args = MagicMock(now=True, store_path=store_path)
 
-        with patch("fenris.monitor.subprocess") as mock_sub:
-            mock_sub.run.return_value = MagicMock(returncode=0)
+        with patch("fenris.monitor.enable_timer") as mock_enable:
             cmd_enable(args)
 
         # Should have a new open period
@@ -155,8 +151,7 @@ class TestDisableIdempotentMatrix:
 
         args = MagicMock(now=True, store_path=store_path)
 
-        with patch("fenris.monitor.subprocess") as mock_sub:
-            mock_sub.run.return_value = MagicMock(returncode=0)
+        with patch("fenris.monitor.disable_timer") as mock_disable:
             cmd_disable(args)
 
         # Period should be closed with user_disabled
@@ -174,8 +169,7 @@ class TestDisableIdempotentMatrix:
 
         args = MagicMock(now=True, store_path=store_path)
 
-        with patch("fenris.monitor.subprocess") as mock_sub:
-            mock_sub.run.return_value = MagicMock(returncode=0)
+        with patch("fenris.monitor.disable_timer") as mock_disable:
             cmd_disable(args)
 
         # No periods should exist
@@ -207,28 +201,19 @@ class TestDisableIdempotentMatrix:
 class TestCollectTrigger:
     """§8.7: On-demand collection via helper path."""
 
-    def test_collect_triggers_systemctl_start(self):
-        """Collect starts fenris-collect.service synchronously."""
+    def test_collect_triggers_init_system(self):
+        """Collect triggers init_system.collect_now."""
         args = MagicMock()
 
-        with patch("fenris.monitor.subprocess") as mock_sub:
-            mock_sub.run.return_value = MagicMock(returncode=0)
+        with patch("fenris.monitor.collect_now") as mock_collect:
             cmd_collect(args)
-
-        mock_sub.run.assert_called_once_with(
-            ["systemctl", "start", "fenris-collect.service"],
-            capture_output=True,
-            text=True,
-        )
+            mock_collect.assert_called_once()
 
     def test_collect_failure_exits_nonzero(self):
         """Collect failure exits with nonzero status."""
         args = MagicMock()
 
-        with patch("fenris.monitor.subprocess") as mock_sub:
-            mock_sub.run.return_value = MagicMock(
-                returncode=1, stderr="Unit not found"
-            )
+        with patch("fenris.monitor.collect_now", side_effect=SystemExit(1)):
             with pytest.raises(SystemExit) as exc_info:
                 cmd_collect(args)
             assert exc_info.value.code == 1

units/runit/fenris-collect/log/run

@@ -0,0 +1,9 @@
+#!/bin/sh
+# fenris-collect runit log script — service output to /var/log/fenris-collect/
+#
+# Runit automatically pipes the service's stdout/stderr to this logger's stdin.
+# The logger writes to runit's log directory for diagnostics.
+#
+# Spec: §8.8 (actionable native diagnostics)
+exec chpst -u fenris:fenris \
+    svlogd -tt /var/log/fenris-collect/

units/runit/fenris-collect/run

@@ -0,0 +1,40 @@
+#!/bin/sh
+# fenris-collect runit run script — periodic NVMe collection scheduler.
+#
+# Runit service layout:
+#   /etc/sv/fenris-collect/run        — this script (scheduler)
+#   /etc/sv/fenris-collect/log/run    — logger to /var/log/fenris-collect/
+#   /var/service/fenris-collect        — symlink to enable
+#   /etc/sv/fenris-collect/down        — marker for dormant install
+#
+# Guarantees (must match systemd timer semantics):
+#   - Initial 2-minute boot delay (sleep 120 before first collect)
+#   - Completion-relative 5-minute cadence (sleep 300 after collect)
+#   - Bounded execution (timeout 90s on each collect)
+#   - No catch-up (fixed sleep interval, no Persistent=)
+#   - Serialized runs (runsv does not restart until exit)
+#   - Serialized on-demand (flock serializes fenris-collect execution)
+#
+# Spec: §8.4, §8.5, §8.6, ADR 0008
+set -eu
+
+COLLECT_TIMEOUT=90
+BOOT_DELAY=120
+CADENCE=300
+LOCK_FILE=/var/lib/fenris/fenris-collect.lock
+
+# Ensure lock directory exists
+mkdir -p "$(dirname "$LOCK_FILE")"
+
+# Initial boot delay: sleep before first collection
+sleep "$BOOT_DELAY"
+
+# Collection loop: collect, then sleep for cadence
+while true; do
+    flock --nonblock "$LOCK_FILE" \
+        timeout "$COLLECT_TIMEOUT" nice ionice -c3 \
+        /usr/libexec/fenris/fenris-collect \
+        2>&1 || true
+
+    sleep "$CADENCE"
+done