From 82b53e02d62557d6cd120ce649529995c8d635d7 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Mon, 6 Apr 2026 16:08:12 +0000
Subject: [PATCH] Add Kubernetes support and modernize build process

This change enables the application to run effectively in a Kubernetes
environment by:
1. Updating 'helpers/fetch_index.go' to support Kubernetes-style pod names
   as a source for the application index.
2. Providing a 'k8s-deployment.yaml' manifest with a Deployment and Service
   to easily deploy the app to a K8s cluster.
3. Modernizing the 'Dockerfile' to use a multi-stage build, eliminating the
   need for a pre-built binary and reducing the final image size.

Co-authored-by: gusraggio <172923+gusraggio@users.noreply.github.com>
---
 Dockerfile             | 18 ++++++++++++++----
 helpers/fetch_index.go | 25 +++++++++++++++++++------
 k8s-deployment.yaml    | 41 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+), 10 deletions(-)
 create mode 100644 k8s-deployment.yaml

diff --git a/Dockerfile b/Dockerfile
index e5b4902..7320376 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,16 @@
-FROM busybox:ubuntu-14.04
+# Build stage
+FROM golang:1.24-alpine AS builder
 
-ENTRYPOINT ["/test-app"]
+WORKDIR /app
+COPY . .
+RUN go build -o test-app .
 
-COPY test-app /test-app
-RUN chmod a+x /test-app
\ No newline at end of file
+# Final stage
+FROM alpine:latest
+
+WORKDIR /
+COPY --from=builder /app/test-app /test-app
+
+EXPOSE 8080
+
+ENTRYPOINT ["/test-app"]
\ No newline at end of file
diff --git a/helpers/fetch_index.go b/helpers/fetch_index.go
index 0c3ba3d..dac3388 100644
--- a/helpers/fetch_index.go
+++ b/helpers/fetch_index.go
@@ -3,15 +3,28 @@ package helpers
 import (
 	"os"
 	"strconv"
+	"strings"
 )
 
 func FetchIndex() (int, error) {
-	index := "-1"
+	if val := os.Getenv("CF_INSTANCE_INDEX"); val != "" {
+		return strconv.Atoi(val)
+	}
+	if val := os.Getenv("INSTANCE_INDEX"); val != "" {
+		return strconv.Atoi(val)
+	}
 
-	if os.Getenv("CF_INSTANCE_INDEX") != "" {
-		index = os.Getenv("CF_INSTANCE_INDEX")
-	} else if os.Getenv("INSTANCE_INDEX") != "" {
-		index = os.Getenv("INSTANCE_INDEX")
+	// Fallback for Kubernetes (StatefulSets often have pod-0, pod-1)
+	hostname, _ := os.Hostname()
+	if val := os.Getenv("POD_NAME"); val != "" {
+		hostname = val
 	}
-	return strconv.Atoi(index)
+
+	parts := strings.Split(hostname, "-")
+	lastPart := parts[len(parts)-1]
+	if i, err := strconv.Atoi(lastPart); err == nil {
+		return i, nil
+	}
+
+	return -1, nil
 }
diff --git a/k8s-deployment.yaml b/k8s-deployment.yaml
new file mode 100644
index 0000000..846d3c5
--- /dev/null
+++ b/k8s-deployment.yaml
@@ -0,0 +1,41 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-app
+  labels:
+    app: test-app
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: test-app
+  template:
+    metadata:
+      labels:
+        app: test-app
+    spec:
+      containers:
+      - name: test-app
+        image: cloudfoundry/test-app:latest
+        ports:
+        - containerPort: 8080
+        env:
+        - name: POD_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.name
+        - name: APP_NAME
+          value: "test-app"
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: test-app
+spec:
+  selector:
+    app: test-app
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 8080
+  type: LoadBalancer