feat(anubis): add /healthz route to metrics server (#843)

* feat(anubis): add /healthz route to metrics server

Also add health check test for Docker Compose and update documentation
for health checking Anubis with Docker Compose.

Signed-off-by: Xe Iaso <me@xeiaso.net>

* chore: spelling

Signed-off-by: Xe Iaso <me@xeiaso.net>

---------

Signed-off-by: Xe Iaso <me@xeiaso.net>

docs/docs/CHANGELOG.md

@@ -103,6 +103,7 @@ There are a bunch of other assorted features and fixes too:
 - The "Try again" button on the error page has been fixed. Previously it meant "try the solution again" instead of "try the challenge again".
 - In certain cases, a user could be stuck with a test cookie that is invalid, locking them out of the service for up to half an hour. This has been fixed with better validation of this case and clearing the cookie.
 - Start exposing JA4H fingerprints for later use in CEL expressions.
+- Add `/healthz` route for use in platform-based health checks.
 
 ### Potentially breaking changes
 

docs/docs/admin/environments/docker-compose.mdx

@@ -4,7 +4,7 @@ Docker compose is typically used in concert with other load balancers such as [A
 
 ```yaml
 services:
-  anubis-nginx:
+  anubis:
     image: ghcr.io/techarohq/anubis:latest
     environment:
       BIND: ":8080"
@@ -15,10 +15,17 @@ services:
       POLICY_FNAME: "/data/cfg/botPolicy.yaml"
       OG_PASSTHROUGH: "true"
       OG_EXPIRY_TIME: "24h"
+    healthcheck:
+      test: ["CMD", "anubis", "--healthcheck"]
+      interval: 5s
+      timeout: 30s
+      retries: 5
+      start_period: 500ms
     ports:
       - 8080:8080
     volumes:
       - "./botPolicy.yaml:/data/cfg/botPolicy.yaml:ro"
+
   nginx:
     image: nginx
     volumes:

docs/manifest/deployment.yaml

@@ -36,6 +36,18 @@ spec:
               mountPath: /conf
           ports:
             - containerPort: 80
+          readinessProbe:
+            httpGet:
+              path: /
+              port: 80
+            initialDelaySeconds: 1
+            periodSeconds: 10
+          livenessProbe:
+            httpGet:
+              path: /
+              port: 80
+            initialDelaySeconds: 10
+            periodSeconds: 20
         - name: anubis
           image: ghcr.io/techarohq/anubis:main
           imagePullPolicy: Always
@@ -80,4 +92,15 @@ spec:
               type: RuntimeDefault
           envFrom:
             - secretRef:
-                name: anubis-docs-thoth
+          readinessProbe:
+            httpGet:
+              path: /healthz
+              port: 9090
+            initialDelaySeconds: 1
+            periodSeconds: 10
+          livenessProbe:
+            httpGet:
+              path: /healthz
+              port: 9090
+            initialDelaySeconds: 10
+            periodSeconds: 20