Add Docker health collector

collectors/docker.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+
+import json
+import subprocess
+
+
+def collect():
+    result = subprocess.run(
+        ["docker", "ps", "-a", "--format", "{{json .}}"],
+        capture_output=True,
+        text=True,
+    )
+
+    if result.returncode != 0:
+        return {
+            "state": "offline",
+            "summary": "Docker error",
+            "detail": result.stderr.strip(),
+        }
+
+    containers = [
+        json.loads(line)
+        for line in result.stdout.splitlines()
+        if line.strip()
+    ]
+
+    running = sum(1 for item in containers if item["State"] == "running")
+    unhealthy = sum(
+        1 for item in containers
+        if "unhealthy" in item.get("Status", "").lower()
+    )
+    exited = sum(1 for item in containers if item["State"] == "exited")
+
+    if unhealthy or exited:
+        state = "warning"
+        detail = f"{unhealthy} unhealthy, {exited} exited"
+    else:
+        state = "online"
+        detail = "All containers running"
+
+    return {
+        "state": state,
+        "summary": f"{running}/{len(containers)} running",
+        "detail": detail,
+        "running": running,
+        "total": len(containers),
+        "unhealthy": unhealthy,
+        "exited": exited,
+    }