Continuing this short series of writing a simple echo service web API along with the docker and k8s requirements, we’re now going to turn our attention to a Go implementation.
Implementation
I’m using JetBrains GoLand for this project, so I created a project named echo_service.
If it doesn’t exist add the go.mod file or update it to have following
module echo_service go 1.24
add a main.go file with the following
package main
import (
"fmt"
"net/http"
)
func livezHandler(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
w.Write([]byte("ok\n"))
}
func readyzHandler(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
w.Write([]byte("ok\n"))
}
func echoHandler(w http.ResponseWriter, r *http.Request) {
text := r.URL.Query().Get("text")
fmt.Fprintf(w, "Go Echo: %s\n", text)
}
func main() {
http.HandleFunc("/echo", echoHandler)
http.HandleFunc("/livez", livezHandler)
http.HandleFunc("/readyz", readyzHandler)
fmt.Println("Echo service running on port 8080...")
err := http.ListenAndServe(":8080", nil)
if err != nil {
fmt.Println("Failed to start the service")
return
}
}
Dockerfile
Next up we need to create our Dockerfile
FROM golang:1.24-alpine WORKDIR /app COPY . . RUN go build -o echo_service . CMD ["./echo_service"]
Note: In Linux port 80 might be locked down, hence we use port 8080 by default.
To build this, run
docker build -t putridparrot.echo_service:v1 .
Don’t forget to change the name to your preferred name.
and to test this, run
docker run -p 8080:8080 putridparrot.echo_service:v1
Kubernetes
If all wen well we’ve not tested our application and see it working from a docker image, so now we need to create the deployment etc. for Kubernete’s. Let’s assume you’ve pushed you image to Docker or another container registry such as Azure – I’m call my container registry putridparrotreg.
I’m also not going to use helm at this point as I just want a (relatively) simple yaml file to run from kubectl, so create a deployment.yaml file, we’ll store all the configurations, deployment, service and ingress in this one file jus for simplicity.
apiVersion: apps/v1
kind: Deployment
metadata:
name: echo
namespace: dev
labels:
app: echo
spec:
replicas: 1
selector:
matchLabels:
app: echo
template:
metadata:
labels:
app: echo
spec:
containers:
- name: echo
image: putridparrotreg/putridparrot.echo_service:v1
ports:
- containerPort: 8080
resources:
requests:
memory: "100Mi"
cpu: "100m"
limits:
memory: "200Mi"
cpu: "200m"
livenessProbe:
httpGet:
path: /livez
port: 8080
initialDelaySeconds: 30
periodSeconds: 10
readinessProbe:
httpGet:
path: /readyz
port: 8080
initialDelaySeconds: 5
periodSeconds: 5
---
apiVersion: v1
kind: Service
metadata:
name: echo_service
namespace: dev
labels:
app: echo
spec:
type: ClusterIP
selector:
app: echo
ports:
- name: http
port: 80
targetPort: 8080
protocol: TCP
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: echo-ingress
namespace: dev
annotations:
kubernetes.io/ingress.class: "nginx"
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- host: mydomain.com
http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: echo_service
port:
number: 80
Don’t forget to change the “host” and image to suit, also this assume you created a namespace “dev” for your app. See Creating a local container registry for information on setting up your own container registry.