Add GitHub Actions CI

Builds and pushes all images when their source changed.

.ci/changed-images

@@ -0,0 +1,39 @@
+#!/bin/bash
+set -euo pipefail
+
+PATH=".ci:$PATH"
+
+syntax=plain
+if [[ "${1:-}" = "--matrix" ]]; then
+    syntax=matrix
+fi
+
+images=()
+for image in * ;do
+    if [[ ! -d "${image}" ]]; then
+        continue
+    fi
+    if ! git-changed "$image" &> /dev/null; then
+        continue
+    fi
+    images+=("$image")
+done
+
+if [[ "$syntax" = plain ]]; then
+    for image in "${images[@]}"; do
+        echo "$image"
+    done
+elif [[ "$syntax" = matrix ]]; then
+    output='{"image":['
+    first=true
+    for image in "${images[@]}"; do
+        if [[ "$first" = true ]]; then
+            first=false
+        else
+            output="$output,"
+        fi
+        output="$output"'"'"$image"'"'
+    done
+    output="$output]}"
+    echo -n "$output"
+fi

.ci/git-changed

@@ -0,0 +1,52 @@
+#!/bin/bash
+set -euo pipefail
+
+path="${1:-$(pwd)}"
+old_ref="origin/master"
+new_ref="HEAD"
+
+if [[ "$(git rev-parse "$old_ref")" = "$(git rev-parse "$new_ref")" ]]; then
+    old_ref="HEAD~1"
+fi
+
+excluded_patterns=(
+    '.*/README.md$'
+)
+
+is_excluded() {
+    local path="$1"
+    for excl in "${excluded_patterns[@]}"; do
+        if [[ "${path}" =~ ${excl} ]]; then
+            return 1
+        fi
+    done
+    return 0
+}
+
+filter_excluded() {
+    while read line; do
+        if ! is_excluded "$line"; then
+            echo "$line"
+        fi
+    done
+}
+
+git_changed_files() {
+    local old="$1"
+    local new="$2"
+    local path="$3"
+    git diff --name-only "$old..$new" -- "$path"
+}
+
+mapfile -t changed_files < <(git_changed_files "$old_ref" "$new_ref" "$path" | filter_excluded)
+
+if [[ ${#changed_files[@]} == 0 ]]; then
+    echo "Nothing changed."
+    exit 1
+else
+    echo "Changes:"
+    for file in "${changed_files[@]}"; do
+        echo "  $file"
+    done
+    exit 0
+fi

.ci/tags-to-json

@@ -0,0 +1,23 @@
+#!/bin/bash
+set -euo pipefail
+
+path="$1"
+tags_path="$path/tags"
+
+if [[ ! -f "$tags_path" ]]; then
+    echo "$tags_path does not exist"
+    exit 1
+fi
+
+output='"'
+first=true
+for tag in $(<"$tags_path"); do
+    if [[ "$first" = true ]]; then
+        first=false
+        output="$output$tag"
+    else
+        output="$output\n$tag"
+    fi
+done
+output="$output"'"'
+echo -n "$output"

.github/workflows/ci.yml

@@ -6,7 +6,66 @@ on:
       - staging
   pull_request: {}
 jobs:
+  set-matrix:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      - uses: actions/checkout@v2
+      - run: '.ci/changed-images'
+      - id: set-matrix
+        run: 'echo "::set-output name=matrix::$(.ci/changed-images --matrix)"'
   build:
+    if: github.ref != 'refs/heads/master'
+    needs: set-matrix
+    runs-on: ubuntu-latest
+    strategy:
+      matrix: ${{fromJson(needs.set-matrix.outputs.matrix)}}
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v2
+      - id: set-tags
+        run: 'echo "::set-output name=tags::$(.ci/tags-to-json "${{ matrix.image }}")"'
+      - uses: docker/setup-buildx-action@v1
+        id: buildx
+        with:
+          version: latest
+          install: true
+          id: docker_build
+      - uses: docker/build-push-action@v2
+        id: docker_build
+        with:
+          push: false
+          tags: ${{ steps.set-tags.outputs.tags }}
+          context: ${{ matrix.image }}
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}
+  build-and-push:
+    if: github.ref == 'refs/heads/master'
+    needs: set-matrix
     runs-on: ubuntu-latest
+    strategy:
+      matrix: ${{fromJson(needs.set-matrix.outputs.matrix)}}
+      fail-fast: false
     steps:
-      - run: echo "hello world"
+      - uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - uses: actions/checkout@v2
+      - id: set-tags
+        run: 'echo "::set-output name=tags::$(.ci/tags-to-json "${{ matrix.image }}")"'
+      - uses: docker/setup-buildx-action@v1
+        id: buildx
+        with:
+          version: latest
+          install: true
+          id: docker_build
+      - uses: docker/build-push-action@v2
+        id: docker_build
+        with:
+          push: true
+          tags: ${{ steps.set-tags.outputs.tags }}
+          context: ${{ matrix.image }}
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}

clang-format/tags

@@ -0,0 +1,2 @@
+hdivsecurity/clang-format:latest
+hdivsecurity/clang-format:10