feat: add demo apps and workflows to build

.github/workflows/build-apps.yml

@@ -0,0 +1,160 @@
+name: Build demo apps
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'apps/**'
+
+jobs:
+  hello-world:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+
+      - name: setup qemu
+        uses: docker/setup-qemu-action@v3
+
+      - name: setup docker
+        uses: docker/setup-buildx-action@v3
+
+      - name: login to ghcr.io
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: docker metadata
+        uses: docker/metadata-action@v5
+        id: hello_world_meta
+        with:
+          images: |
+            ghcr.io/${{ github.repository }}/apps/hello-world
+          tags: |
+            type=sha,format=long
+            type=raw,value=latest,enable=${{ github.ref == format('refs/heads/{0}', 'main') }}
+
+      - name: build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: /apps/hello-world
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.hello_world_meta.outputs.tags }}
+          labels: ${{ steps.hello_world_meta.outputs.labels }}
+
+  probes:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+
+      - name: setup qemu
+        uses: docker/setup-qemu-action@v3
+
+      - name: setup docker
+        uses: docker/setup-buildx-action@v3
+
+      - name: login to ghcr.io
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: docker metadata
+        uses: docker/metadata-action@v5
+        id: probe_meta
+        with:
+          images: |
+            ghcr.io/${{ github.repository }}/apps/probes
+          tags: |
+            type=sha,format=long
+            type=raw,value=latest,enable=${{ github.ref == format('refs/heads/{0}', 'main') }}
+
+      - name: build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: /apps/probes
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.probe_meta.outputs.tags }}
+          labels: ${{ steps.probe_meta.outputs.labels }}
+
+  blue-green:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+
+      - name: setup qemu
+        uses: docker/setup-qemu-action@v3
+
+      - name: setup docker
+        uses: docker/setup-buildx-action@v3
+
+      - name: login to ghcr.io
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: docker metadata (blue)
+        uses: docker/metadata-action@v5
+        id: blue_meta
+        with:
+
+          images: |
+            ghcr.io/${{ github.repository }}/apps/blue-green
+          tags: |
+            type=sha,format=long
+            type=raw,value=blue
+
+      - name: docker metadata (green)
+        uses: docker/metadata-action@v5
+        id: green_meta
+        with:
+          images: |
+            ghcr.io/${{ github.repository }}/apps/blue-green
+          tags: |
+            type=sha,format=long
+            type=raw,value=green
+
+      - name: build and push (blue)
+        uses: docker/build-push-action@v5
+        with:
+          context: /apps/blue-green
+          platforms: linux/amd64,linux/arm64
+          build-args: |
+            IS_BLUE=true
+          push: true
+          tags: ${{ steps.green_meta.outputs.tags }}
+          labels: ${{ steps.green_meta.outputs.labels }}
+
+      - name: build and push (green)
+        uses: docker/build-push-action@v5
+        with:
+          context: /apps/blue-green
+          platforms: linux/amd64,linux/arm64
+          build-args: |
+            IS_BLUE=false
+          push: true
+          tags: ${{ steps.green_meta.outputs.tags }}
+          labels: ${{ steps.green_meta.outputs.labels }}
+

apps/blue-green/Dockerfile

@@ -0,0 +1,19 @@
+FROM golang:1.22 as builder
+
+ARG IS_BLUE=true
+
+WORKDIR /go/src/app
+
+COPY . .
+
+RUN go mod download
+
+RUN CGO_ENABLED=0 GOOS=linux go build -ldflags "-X main.IsBlue=${IS_BLUE}" -a -installsuffix cgo -o blue-green .
+
+FROM debian:bookwork-slim as runtime
+
+WORKDIR /app
+
+COPY --from=builder /go/src/app/blue-green .
+
+CMD [ "/app/blue-green" ]

apps/blue-green/go.mod

@@ -0,0 +1,5 @@
+module github.com/vojtechmares/kubernetes-training/apps/blue-green
+
+go 1.22.0
+
+require github.com/google/uuid v1.6.0 // indirect

apps/blue-green/go.sum

@@ -0,0 +1,2 @@
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=

apps/blue-green/main.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+	"text/template"
+
+	"github.com/google/uuid"
+)
+
+var IsBlue string = "true"
+
+const html = `
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Hello, Kubernetes! | {{ .Hostname }}</title>
+  <style>
+    body {
+      font-family: Helvetica;
+      background-color: {{ .Color }};
+      color: #fff;
+    }
+    pre {
+      margin: 0.25rem 0;
+      font-size: 1.5rem;
+    }
+  </style>
+</head>
+<body>
+  <div style="display: flex; flex-direction: column; justify-content: center; align-items: center;">
+    <h1 style="font-size: 4rem;">Hello, Kubernetes! 👋</h1>
+    <pre>hostname: {{ .Hostname }}</pre>
+    <pre>instanceID: {{ .InstanceID }}</pre>
+  </div>
+</body>
+</html>
+`
+
+func main() {
+	instanceID := uuid.New().String()
+	hostname, err := os.Hostname()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var hexColor string = "#15803d" // green
+
+	isBlue, err := strconv.ParseBool(IsBlue)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if isBlue {
+		hexColor = "#1d4ed8"
+	}
+
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		tpl, err := template.New("index.html").Parse(html)
+		if err != nil {
+			log.Println(err)
+			w.Write([]byte(fmt.Sprintf("Error: %s", err)))
+			return
+		}
+
+		err = tpl.Execute(w, map[string]string{"Hostname": hostname, "InstanceID": instanceID, "Color": hexColor})
+		if err != nil {
+			log.Println(err)
+			w.Write([]byte(fmt.Sprintf("Error: %s", err)))
+			return
+		}
+
+		w.Header().Set("Content-Type", "text/html")
+	})
+
+	log.Println("Starting server on :8080")
+	http.ListenAndServe(":8080", nil)
+}

apps/hello-world/Dockerfile

@@ -0,0 +1,17 @@
+FROM golang:1.22 as builder
+
+WORKDIR /go/src/app
+
+COPY . .
+
+RUN go mod download
+
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o hello-world .
+
+FROM debian:bookwork-slim as runtime
+
+WORKDIR /app
+
+COPY --from=builder /go/src/app/hello-world .
+
+CMD [ "/app/hello-world" ]

apps/hello-world/go.mod

@@ -0,0 +1,5 @@
+module github.com/vojtechmares/kubernetes-training/apps/probes
+
+go 1.22.0
+
+require github.com/google/uuid v1.6.0

apps/hello-world/go.sum

@@ -0,0 +1,2 @@
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=

apps/hello-world/main.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"text/template"
+
+	"github.com/google/uuid"
+)
+
+const html = `
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Hello, Kubernetes! | {{ .Hostname }}</title>
+  <style>
+    body {
+      font-family: Helvetica;
+    }
+    pre {
+      margin: 0.25rem 0;
+      font-size: 1.5rem;
+    }
+  </style>
+</head>
+<body style="font-family: Helvetica">
+  <div style="display: flex; flex-direction: column; justify-content: center; align-items: center;">
+    <h1 style="font-size: 4rem;">Hello, Kubernetes! 👋</h1>
+    <pre>hostname: {{ .Hostname }}</pre>
+    <pre>instanceID: {{ .InstanceID }}</pre>
+  </div>
+</body>
+</html>
+`
+
+func main() {
+	instanceID := uuid.New().String()
+	hostname, err := os.Hostname()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		tpl, err := template.New("index.html").Parse(html)
+		if err != nil {
+			log.Println(err)
+			w.Write([]byte(fmt.Sprintf("Error: %s", err)))
+			return
+		}
+
+		err = tpl.Execute(w, map[string]string{"Hostname": hostname, "InstanceID": instanceID})
+		if err != nil {
+			log.Println(err)
+			w.Write([]byte(fmt.Sprintf("Error: %s", err)))
+			return
+		}
+
+		w.Header().Set("Content-Type", "text/html")
+	})
+
+	log.Println("Starting server on :8080")
+	http.ListenAndServe(":8080", nil)
+}

apps/probes/Dockerfile

@@ -0,0 +1,17 @@
+FROM golang:1.22 as builder
+
+WORKDIR /go/src/app
+
+COPY . .
+
+RUN go mod download
+
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o probes .
+
+FROM debian:bookwork-slim as runtime
+
+WORKDIR /app
+
+COPY --from=builder /go/src/app/probes .
+
+CMD [ "/app/probes" ]

apps/probes/go.mod

@@ -0,0 +1,4 @@
+module github.com/vojtechmares/kubernetes-training/apps/probes
+
+go 1.22.0
+

apps/probes/go.sum

@@ -0,0 +1,2 @@
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=