k/forgejo: add robots to ban facebook/meta

kustomizations/forgejo/ingress.yaml

@@ -19,6 +19,13 @@ spec:
             name: forgejo
             port:
               number: 80
+      - path: /robots.txt
+        pathType: Exact
+        backend:
+          service:
+            name: robots
+            port:
+              number: 80
   tls:
   - hosts:
     - git.distrust.co

kustomizations/forgejo/kustomization.yaml

@@ -5,6 +5,7 @@ resources:
 - namespace.yaml
 - resources.yaml
 - ingress.yaml
+- robots.yaml
 - snapshots
 patches:
 - path: forgejo-env-vars.patch.yaml

kustomizations/forgejo/robots.yaml

@@ -0,0 +1,50 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: robots
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: robots
+  template:
+    metadata:
+      labels:
+        app: robots
+    spec:
+      containers:
+      - name: robots
+        image: nginx
+        ports:
+        - containerPort: 80
+        volumeMounts:
+        - name: robots-txt
+          mountPath: /usr/share/nginx/html
+      volumes:
+      - name: robots-txt
+        configMap:
+          name: robots-txt
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: robots-txt
+data:
+  # Facebook/Meta have a web crawler that absolutely _spams_ Forgejo when
+  # large repositories exist. It's nonstop requests.
+  robots.txt: |-
+    User-agent: facebookexternalhit
+    User-agent: meta-externalagent
+    Disallow: /
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: robots
+spec:
+  ports:
+  - name: http
+    port: 80
+    targetPort: 80
+  selector:
+    app: robots