Feature: Added ci.yaml and operation files for docker swarm.

.github/workflows/ci.yaml

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+name: Docker
+
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+
+on:
+  schedule:
+    - cron: '22 21 * * *'
+  push:
+    branches: [ "main" ]
+    # Publish semver tags as releases.
+    tags: [ 'v*.*.*' ]
+  pull_request:
+    branches: [ "main" ]
+
+env:
+  # Use docker.io for Docker Hub if empty
+  REGISTRY: ghcr.io
+  # github.repository as <account>/<repo>
+  IMAGE_NAME: ${{ github.repository }}
+
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      # This is used to complete the identity challenge
+      # with sigstore/fulcio when running outside of PRs.
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      # Install the cosign tool except on PR
+      # https://github.com/sigstore/cosign-installer
+      - name: Install cosign
+        if: github.event_name != 'pull_request'
+        uses: sigstore/cosign-installer@6e04d228eb30da1757ee4e1dd75a0ec73a653e06 #v3.1.1
+        with:
+          cosign-release: 'v2.1.1'
+
+      # Set up BuildKit Docker container builder to be able to build
+      # multi-platform images and export cache
+      # https://github.com/docker/setup-buildx-action
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@f95db51fddba0c2d1ec667646a06c2ce06100226 # v3.0.0
+
+      # Login against a Docker registry except on PR
+      # https://github.com/docker/login-action
+      - name: Log into registry ${{ env.REGISTRY }}
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.0.0
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      # Extract metadata (tags, labels) for Docker
+      # https://github.com/docker/metadata-action
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@96383f45573cb7f253c731d3b3ab81c87ef81934 # v5.0.0
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+
+      # Build and push Docker image with Buildx (don't push on PR)
+      # https://github.com/docker/build-push-action
+      - name: Build and push Docker image
+        id: build-and-push
+        uses: docker/build-push-action@0565240e2d4ab88bba5387d719585280857ece09 # v5.0.0
+        with:
+          context: .
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+      # Sign the resulting Docker image digest except on PRs.
+      # This will only write to the public Rekor transparency log when the Docker
+      # repository is public to avoid leaking data.  If you would like to publish
+      # transparency data even for private images, pass --force to cosign below.
+      # https://github.com/sigstore/cosign
+      - name: Sign the published Docker image
+        if: ${{ github.event_name != 'pull_request' }}
+        env:
+          # https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
+          TAGS: ${{ steps.meta.outputs.tags }}
+          DIGEST: ${{ steps.build-and-push.outputs.digest }}
+        # This step uses the identity token to provision an ephemeral certificate
+        # against the sigstore community Fulcio instance.
+        run: echo "${TAGS}" | xargs -I {} cosign sign --yes {}@${DIGEST}

Dockerfile

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+FROM ubuntu:20.04
+RUN apt-get update && apt-get install -y python3
+COPY . .
+CMD ["python3", "test-node.py"]

operation/delete.sh

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+#!/bin/bash
+
+if [ "$EUID" -ne 0 ]; then 
+    echo "Run as root."
+else
+    docker service rm q-service
+    docker swarm leave --force
+
+    echo "Service deleted."
+fi

operation/initialize.sh

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+#!/bin/bash
+
+if [ "$EUID" -ne 0 ]; then 
+    echo "Run as root."
+else
+    docker image build -t q-node .
+
+    docker swarm leave --force
+    docker swarm init --advertise-addr 192.168.99.100
+
+    docker service create --replicas 1 --name q-service q-node
+
+    echo "Service initialized."
+fi

operation/scale.sh

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+#!/bin/bash
+
+if [ "$EUID" -ne 0 ]; then 
+    echo "Run as root."
+else
+    if [ ! "$#" -eq 1 ]; then
+        echo "1 argument required, $# provided."
+        return 1
+    fi
+    if ! [[ $1 =~ ^[0-9]+$ ]]; then
+        echo "Numeric argument required, $1 provided."
+        return 1
+    fi
+    if [ $1 -gt 10 -o $1 -lt 1 ]; then
+        echo "Value $1 is too big or too small."; return 1
+    fi
+
+    docker service scale q-service=$1
+
+    echo "Service scaled to $1."
+fi

test-node.py

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+import time
+
+if __name__ == '__main__':
+    print('Hello World!', flush=True)
+    while True:
+        time.sleep(2)