Added container build workflow (#94)

* added container build workflow

* remove unneeded env var

.github/images/alpine:3.Dockerfile

@@ -0,0 +1,24 @@
+# to build the image locally tagged with the short commit hash:
+# docker build -t bgpq4:$(git rev-parse --short HEAD) -f .github/images/alpine:3.Dockerfile .
+ARG IMAGE=alpine:3
+FROM $IMAGE as builder
+
+# Install dependencies
+RUN apk upgrade
+RUN apk add autoconf automake file gcc gzip libtool make musl-dev
+
+# Add source code
+ADD . /src
+WORKDIR /src
+
+# Run steps
+RUN ./bootstrap
+RUN ./configure
+RUN make
+RUN make check
+RUN make distcheck
+
+FROM alpine:3
+COPY --from=builder /src/bgpq4 /bgp/
+WORKDIR /bgp
+ENTRYPOINT [ "./bgpq4" ]

.github/workflows/build-container.yml

@@ -0,0 +1,64 @@
+name: Container build
+"on":
+  push:
+    tags:
+      - "*" # Push events to any tag
+    branches:
+      - "main"
+
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: "Container tag to use for the build"
+        required: true
+        default: "test"
+
+jobs:
+  test:
+    uses: ./.github/workflows/unit-tests.yml
+
+  build:
+    name: Build container
+    runs-on: ubuntu-22.04
+    needs: test
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - # Add support for more platforms with QEMU
+        # https://github.com/docker/setup-qemu-action
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ghcr.io/${{ github.repository_owner }}/bgpq4
+          tags: |
+            # pick up tag provided from workflow_dispatch user's input
+            type=raw,value=${{ inputs.tag }}
+            type=ref,event=tag
+            type=ref,event=branch
+            # git short commit
+            type=sha
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v4
+        with:
+          file: .github/images/alpine:3.Dockerfile
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}

.github/workflows/unit-tests.yml

@@ -8,6 +8,7 @@ on:
       - reopened
       - ready_for_review
       - synchronize
+  workflow_call:
 
 jobs:
   output-unit-tests:

README.md

@@ -447,6 +447,31 @@ Linux can be tuned in the following way:
 
 	sysctl -w net.ipv4.tcp_wmem="4096 65536 2097152"
 
+# CONTAINER IMAGE
+
+A multi-arch (linux/amd64 and linux/arm64) container image is built automatically for all tagged releases and `main` branch. The image is based on Alpine Linux and is available on [GitHub Container Registry](https://github.com/bgp/bgpq4/pkgs/container/bgpq4).
+
+Using the image is as simple as:
+
+	```
+	docker run --rm ghcr.io/bgp/bgpq4:latest -Jl eltel AS20597
+	policy-options {
+		replace:
+		prefix-list eltel {
+			81.9.0.0/20;
+			81.9.32.0/20;
+			81.9.96.0/20;
+			81.222.128.0/20;
+			81.222.160.0/20;
+			81.222.192.0/18;
+			85.249.8.0/21;
+			85.249.224.0/19;
+			89.112.0.0/17;
+			217.170.64.0/19;
+		}
+		}
+	```
+
 # BUILDING
 
 This project uses autotools. If you are building from the repository,