add readiness probe

htmx_patterns/zpages/router.py

@@ -0,0 +1,91 @@
+from datetime import datetime, timezone
+from kubernetes import client, config as kubernetes_config
+from kubernetes.config.config_exception import ConfigException
+import os
+from pydantic import BaseModel
+
+from fastapi import APIRouter
+
+from htmx_patterns.config import get_config
+
+zpages_router = APIRouter(tags=["zpages"])
+
+config = get_config()
+
+
+def format_uptime(seconds: int) -> str:
+    minutes, sec = divmod(seconds, 60)
+    hours, min = divmod(minutes, 60)
+    days, hr = divmod(hours, 24)
+
+    parts = []
+    if days:
+        parts.append(f"{days}d")
+    if hr:
+        parts.append(f"{hr}h")
+    if min:
+        parts.append(f"{min}m")
+    parts.append(f"{sec}s")
+
+    return " ".join(parts)
+
+
+class PodInfo(BaseModel):
+    pod_name: str
+    namespace: str
+    node_name: str
+    container_image: str
+    start_time: str
+    pod_uptime: str
+
+
+class Ready(BaseModel):
+    ready: bool
+    timestamp: str
+    app_version: str
+
+    pod_info: PodInfo
+
+
+def get_pod_info():
+    pod_name = os.getenv("KUBERNETES_POD_NAME")
+    namespace = os.getenv("KUBERNETES_POD_NAMESPACE")
+
+    try:
+        kubernetes_config.load_incluster_config()
+    except ConfigException:
+        return PodInfo(
+            pod_name="unknown",
+            namespace="unknown",
+            node_name="unknown",
+            pod_ip="unknown",
+            container_image="unknown",
+            start_time="unknown",
+            pod_uptime="unknown",
+        )
+    v1 = client.CoreV1Api()
+    pod = v1.read_namespaced_pod(name=pod_name, namespace=namespace)
+    start_time = pod.status.start_time
+    now = datetime.now(timezone.utc)
+    uptime_seconds = int((now - start_time).total_seconds())
+
+    return PodInfo(
+        pod_name=pod.metadata.name,
+        namespace=pod.metadata.namespace,
+        node_name=pod.spec.node_name,
+        container_image=pod.spec.containers[0].image,
+        start_time=pod.status.start_time,
+        pod_uptime=format_uptime(uptime_seconds),
+    )
+
+
+@zpages_router.get("/readyz")
+async def root() -> Ready:
+    pod_info = get_pod_info()
+    ready = Ready(
+        ready=True,
+        timestamp=datetime.now(timezone.utc).isoformat(),
+        app_version=config.app_version,
+        pod_info=pod_info,
+    )
+    return ready