Publish Docker image (#220)

.github/workflows/publish-docker.sh

@@ -0,0 +1,45 @@
+#!/bin/bash
+# Tag and publish Docker image
+
+set -euo pipefail
+
+echo "$DOCKERHUB_TOKEN" | (set -x && docker login --username "$DOCKERHUB_USERNAME" --password-stdin)
+echo "$GHCR_TOKEN" | (set -x && docker login ghcr.io --username "$GHCR_USERNAME" --password-stdin)
+
+# Tag and push docker image
+function docker_push {
+    src=$1
+    dst=$2
+    echo  # newline
+
+    (
+        set -x
+        docker tag "$src" "$dst"
+        docker push "$dst"
+    )
+}
+
+# Publish image to both Docker Hub and GitHub Container Registry
+function publish {
+    tag=$1
+    docker_push "$SRC_IMAGE" "$DOCKERHUB_IMAGE:$tag"
+    docker_push "$SRC_IMAGE" "$GHCR_IMAGE:$tag"
+}
+
+# Publish current branch/tag (e.g. `main` or `v1.2.3`)
+ver=${GITHUB_REF##*/}
+publish "$ver"
+
+# Publish major/minor/latest for version tags
+if [[ "$GITHUB_REF" = refs/tags/v* ]]; then
+    major_ver=${ver%%.*}  # e.g. `v1`
+    publish "$major_ver"
+
+    minor_ver=${ver%.*}  # e.g. `v1.2`
+    publish "$minor_ver"
+
+    publish "latest"
+fi
+
+# Clear credentials
+rm -f ~/.docker/config.json