Add extract-metadata github action

Author: Tuomas Kaittola

.github/workflows/test-extract-metadata-action.yml

@@ -0,0 +1,27 @@
+name: Test extract-metadata action
+
+on:
+  push:
+  pull_request:
+    branches: [main]
+
+jobs:
+  test-extract-metadata:
+    name: Retrieves metadata
+    runs-on: ubuntu-20.04
+
+    steps:
+      - name: Check that environment is empty
+        run: '[[ -z "$IMAGE_NAME" && -z "$COMMIT_ID" && -z "$BRANCH_NAME" ]]'
+
+      - name: Call action to initialize environment
+        uses: HSLdevcom/jore4-tools/github-actions/extract-metadata@extract-metadata-v1
+
+      - name: Environment variables are set after action is called
+        run: '[[ -n "$IMAGE_NAME" && -n "$COMMIT_ID" && -n "$BRANCH_NAME" ]]'
+
+      - name: Check that IMAGE_NAME environment variable is created and is valid
+        run: '[[ "$IMAGE_NAME" == "hsldevcom/jore4-tools" ]]'
+
+        # (tests for BRANCH_NAME and COMMIT_ID omitted for now as they might change on each run so its a little bit tricky to test those)
+

README.md

@@ -9,7 +9,8 @@ Tools which are commonly used by other JORE4 projects
 - [Tools for Docker](#tools-for-docker)
   - [read-secrets.sh](#read-secretssh)
 - [Github Actions](#github-actions)
-  - [Healthcheck](#healthcheck)
+  - [extract-metadata](#extract-metadata)
+  - [healthcheck](#healthcheck)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
@@ -59,7 +60,23 @@ CMD /bin/bash -c "source /tmp/read-secrets.sh && java -jar /.../xxx.jar"
 
 ## Github Actions
 
-### Healthcheck
+### extract-metadata
+
+Extracts Github repository metadata in Docker Hub friendly format.
+
+Example usage:
+
+```
+steps:
+- uses: HSLdevcom/jore4-tools/github-actions/extract-metadata@extract-metadata-v1
+```
+
+After calling this action defines following environment variables that are available in later steps:
+`BRANCH_NAME`: branch name, e.g. `main`. Should work also in pull requests unlike `GITHUB_HEAD_REF` that Github automatically provides.
+`IMAGE_NAME`: repository name in lowercase format, including organization. E.g. `hsldevcom/jore4-tools`. Can be used as docker image name.
+`COMMIT_ID`: commit details in format `<branch name>--<git commit hash>`. Can be used when tagging docker images.
+
+### healthcheck
 
 Runs a user-defined script to check whether a service is up and running
 

github-actions/extract-metadata/action.yml

@@ -0,0 +1,36 @@
+name: "Extract git metadata"
+description:
+  "Extracts repository metadata to environment variables. Useful e.g. when tagging docker images according to jore4 project conventions."
+
+runs:
+  using: "composite"
+  steps:
+    - name: Extract branch name
+      id: branch-name
+      run: |
+        # In pull requests
+          BRANCH_NAME="${GITHUB_HEAD_REF}"
+          [[ ${BRANCH_NAME} = "" ]] && {
+            # In branch pushes
+            BRANCH_NAME="$(echo "${GITHUB_REF}" | cut -d '/' -f 3-)"
+          }
+          echo "BRANCH_NAME=${BRANCH_NAME}" >> "${GITHUB_ENV}"
+      shell: bash
+
+    - name: Extract docker image name
+      id: image-name
+      run: |
+        # GITHUB_REPOSITORY env variable is provided by GitHub and it
+        # contains owner and repository name, e.g. `HSLdevcom/jore4-tools`.
+        # Jore4 project convention is that docker images are named accordingly.
+        #
+        # Docker Hub uses lowercase so use a bashism to convert.
+        echo "IMAGE_NAME=${GITHUB_REPOSITORY,,}" >> $GITHUB_ENV
+      shell: bash
+
+    - name: Extract commit id
+      id: commit-id
+      run: |
+        # Docker tags can use only some special characters.
+        echo "COMMIT_ID=$(echo "${BRANCH_NAME}" | tr -C '0-9a-zA-Z._' '-')-${GITHUB_SHA}" >> $GITHUB_ENV
+      shell: bash