Allow to hash by document_id

charts/document-engine/templates/deployment.yaml

@@ -203,13 +203,34 @@ spec:
           lifecycle:
             {{- toYaml . | nindent 12 }}
           {{- end }}
+      {{- if .Values.nginxSidecar.enabled }}
+        - name: nginx-sidecar
+          image: {{ .Values.nginxSidecar.image }}
+          imagePullPolicy: IfNotPresent
+          ports:
+            - name: nginx
+              containerPort: {{ .Values.nginxSidecar.port }}
+              protocol: TCP
+          resources:
+            {{- toYaml .Values.nginxSidecar.resources | nindent 12 }}
+          volumeMounts:
+            - name: nginx-config
+              mountPath: /etc/nginx/nginx.conf
+              subPath: nginx.conf
+      {{- end }}
       {{- if .Values.sidecars }}
         {{ toYaml .Values.sidecars | nindent 8 }}
       {{- end }}
       {{- if or .Values.extraVolumeMounts
-                .Values.certificateTrust.digitalSignatures 
-                .Values.certificateTrust.customCertificates }}
+                .Values.certificateTrust.digitalSignatures
+                .Values.certificateTrust.customCertificates
+                .Values.nginxSidecar.enabled }}
       volumes:
+        {{- if .Values.nginxSidecar.enabled }}
+        - name: nginx-config
+          configMap:
+            name: {{ include "document-engine.fullname" . }}-nginx-sidecar
+        {{- end }}
         {{- with .Values.extraVolumes }}
         {{ toYaml . | nindent 8 }}
         {{- end }}

charts/document-engine/templates/nginx-sidecar-configmap.yaml

@@ -0,0 +1,63 @@
+{{- if .Values.nginxSidecar.enabled -}}
+{{- $fullName := include "document-engine.fullname" . -}}
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: {{ $fullName }}-nginx-sidecar
+  labels:
+    {{- include "document-engine.labels" . | nindent 4 }}
+data:
+  nginx.conf: |
+    events {
+      worker_connections 1024;
+    }
+
+    http {
+      # Extract document ID from URI
+      map $uri $document_id {
+        default "";
+        ~^/api/documents/([a-zA-Z0-9._~-]+)           $1;
+        ~^/i/d/([a-zA-Z0-9._~-]+)                     $1;
+        ~^/documents/([a-zA-Z0-9._~-]+)               $1;
+        ~^/dashboard/api/document/([a-zA-Z0-9._~-]+)  $1;
+      }
+
+      # Use hash_key for routing decision
+      map $document_id $hash_key {
+        default $request_id;
+        "~."    $document_id;
+      }
+
+      resolver kube-dns.kube-system.svc.cluster.local valid=5s;
+
+      upstream document_engine_backend {
+        # Resolve DNS to get all pod IPs from headless service
+        server {{ $fullName }}-headless.{{ .Release.Namespace }}.svc.cluster.local:{{ .Values.service.port }} resolve;
+
+        # Consistent hash based on document ID
+        hash $hash_key consistent;
+      }
+
+      server {
+        listen {{ .Values.nginxSidecar.port }};
+
+        location / {
+          # Add debug headers
+          add_header X-Hash-Key $hash_key always;
+          add_header X-Pod-Name $hostname always;
+
+          # Forward to consistent backend
+          proxy_pass http://document_engine_backend;
+          proxy_set_header Host $host;
+          proxy_set_header X-Real-IP $remote_addr;
+          proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+          proxy_set_header X-Forwarded-Proto $scheme;
+
+          # Timeouts
+          proxy_connect_timeout 60s;
+          proxy_send_timeout 60s;
+          proxy_read_timeout 60s;
+        }
+      }
+    }
+{{- end }}

charts/document-engine/templates/service-headless.yaml

@@ -0,0 +1,17 @@
+{{- if .Values.nginxSidecar.enabled -}}
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ include "document-engine.fullname" . }}-headless
+  labels:
+    {{- include "document-engine.labels" . | nindent 4 }}
+spec:
+  clusterIP: None
+  selector:
+    {{- include "document-engine.selectorLabels" . | nindent 4 }}
+  ports:
+    - port: {{ .Values.service.port }}
+      targetPort: api
+      protocol: TCP
+      name: api
+{{- end }}

charts/document-engine/templates/service.yaml

@@ -18,7 +18,11 @@ spec:
   {{- end }}
   ports:
     - port: {{ .Values.service.port }}
+      {{- if .Values.nginxSidecar.enabled }}
+      targetPort: nginx
+      {{- else }}
       targetPort: api
+      {{- end }}
       protocol: TCP
       name: api
     {{- with .Values.observability.metrics.prometheusEndpoint }}

charts/document-engine/values.yaml

@@ -890,6 +890,29 @@ extraIngresses: {}
   #           pathType: Prefix
   #   tls: []
 
+# -- (object) Nginx sidecar for consistent hashing by document ID
+# @section -- C. Networking
+# @notationType -- reference
+nginxSidecar:
+  # -- Enable nginx sidecar for consistent hashing
+  # @section -- C. Networking
+  enabled: false
+  # -- Nginx sidecar image
+  # @section -- C. Networking
+  image: nginx:1.25-alpine
+  # -- Port where nginx sidecar listens
+  # @section -- C. Networking
+  port: 8080
+  # -- Resource limits for nginx sidecar
+  # @section -- C. Networking
+  resources:
+    limits:
+      cpu: 100m
+      memory: 128Mi
+    requests:
+      cpu: 50m
+      memory: 64Mi
+
 # https://editor.networkpolicy.io/
 # -- (object) [Network policy](https://kubernetes.io/docs/concepts/services-networking/network-policies/)
 # @section -- C. Networking