Web Echo App

A simple web based application that prints a message on a coloured background, both of which can be configured using environment variables.

Usage

To start the web application, configure the following optional environment variables:

• HOSTPORT=0.0.0.0:8080
• MESSAGE="CloudAcademy ❤ DevOps"
• BACKGROUND_COLOR=yellow
• AUTO_RELOAD=30

Build

The following commands can be used to build and package the source code:

Current operating system:

go build .

Linux operating system:

CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o webapp

macOS operating system:

CGO_ENABLED=0 GOOS=darwin GOARCH=amd64 go build -o webapp

Docker:

docker buildx build --platform=linux/amd64 -t cloudacademydevops/webappecho .

Startup:

Example 1:

./webapp

Example 2:

HOSTPORT=0.0.0.0:8080 MESSAGE="CloudAcademy ❤ DevOps" BACKGROUND_COLOR=cyan ./webapp

Example 3:

HOSTPORT=0.0.0.0:8080 MESSAGE="CloudAcademy ❤ DevOps" BACKGROUND_COLOR=yellow AUTO_RELOAD=30 ./webapp

Docker

The web application has been packaged into a Docker image. The Docker image can be pulled with the following command:

docker pull cloudacademydevops/webappecho

Use the following command to launch the web echoing application within Docker:

docker run --name webapp \
--env MESSAGE=CloudAcademy \
--env BACKGROUND_COLOR=yellow \
--env AUTO_RELOAD=30 \
-p 8080:8080 cloudacademydevops/webappecho

Kubernetes

Use the following command to launch the web echoing application as a Deployment resource within a cluster:

cat << EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: webecho
  namespace: cloudacademy
  labels:
    app: webecho
    version: v1
spec:
  replicas: 2
  selector:
    matchLabels:
      app: webecho
      version: v1
  template:
    metadata:
      labels:
        app: webecho
        version: v1
    spec:
      containers:
      - name: webecho
        image: cloudacademydevops/webappecho
        imagePullPolicy: IfNotPresent
        command: ["/go/bin/webapp"]
        ports:
        - containerPort: 8080
        env:
        - name: MESSAGE
          value: "CloudAcademy ❤ DevOps"
        - name: BACKGROUND_COLOR
          value: yellow
        - name: AUTO_RELOAD
          value: 30
EOF