feat(poimen): restrict the GraphQL server to the memory proxy (#104)

Co-authored-by: rock <[email protected]>

k8s/infra/poimen/graphql-netpol.yaml

@@ -0,0 +1,28 @@
+---
+# Keep the GraphQL server reachable only from the one service that proxies it.
+#
+# poimen-graphql is already off the internet: its Service is ClusterIP on 8090 and
+# no Ingress names it. What it lacked is in-cluster isolation — a ClusterIP answers
+# every pod in the cluster.
+#
+# The only caller is poimen-memory, whose /graphql route forwards the request body
+# to MEM_GQL_PORT (8090). No other workload references this service.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: poimen-graphql-ingress
+  namespace: poimen
+spec:
+  podSelector:
+    matchLabels:
+      app.kubernetes.io/name: poimen-graphql
+  policyTypes:
+    - Ingress
+  ingress:
+    - from:
+        - podSelector:
+            matchLabels:
+              app.kubernetes.io/name: poimen-memory
+      ports:
+        - protocol: TCP
+          port: 8090