compatible: Add release_charm.yaml (#20)

## Issue

[canonical/charming-actions/upload-charm](https://github.com/canonical/charming-actions/tree/main/upload-charm)
does not support multiple series

[DPE-1273](https://warthogs.atlassian.net/browse/DPE-1273)

Also resolves [design
bug](https://chat.canonical.com/canonical/pl/sjwya3bo3fd75ni4zbk5caqxsw)
## Solution
Replace charming-actions/upload-charm with a reusable workflow + Python
script (so it's easier to maintain)

.github/workflows/_get_workflow_version.yaml

@@ -88,16 +88,16 @@ jobs:
               try:
                   os.makedirs(repository_name)
               except FileExistsError:
-                  pass
+                  commands = [f"git checkout {ref}"]
               else:
                   commands = [
                       "git init",
                       "git sparse-checkout set --sparse-index .github/workflows/",
                       f"git remote add --fetch origin https://github.com/{repository_name}.git",
-                      f"git pull origin {ref}",
+                      f"git checkout {ref}",
                   ]
-                  for command in commands:
-                      subprocess.check_output(command.split(" "), cwd=repository_name)
+              for command in commands:
+                  subprocess.check_output(command.split(" "), cwd=repository_name)
           
               jobs = yaml.safe_load(caller_workflow_file_path.read_text())["jobs"]
               versions_ = set()

.github/workflows/build_charm_without_cache.md

@@ -0,0 +1,11 @@
+Workflow file: [build_charm_without_cache.yaml](build_charm_without_cache.yaml)
+
+## Usage
+```yaml
+# Copyright 2023 Canonical Ltd.
+# See LICENSE file for licensing details.
+jobs:
+  build:
+    name: Build charm
+    uses: canonical/data-platform-workflows/.github/workflows/build_charm_without_cache.yaml@v2
+```

.github/workflows/build_charm_without_cache.yaml

@@ -0,0 +1,59 @@
+# Copyright 2023 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+# Usage documentation: build_charm_without_cache.md
+
+on:
+  workflow_call:
+    inputs:
+      artifact-name:
+        description: Packed charm is uploaded to this GitHub artifact name
+        default: charm-packed-without-cache
+        type: string
+      path-to-charm-directory:
+        description: Relative path to charm directory from repository directory
+        default: .
+        type: string
+    outputs:
+      artifact-name:
+        description: Packed charm is uploaded to this GitHub artifact name
+        value: ${{ inputs.artifact-name }}
+
+jobs:
+  build:
+    name: Build charm
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Setup environment
+        # TODO: Replace with custom image on self-hosted runner
+        run: |
+          # Copied from https://github.com/charmed-kubernetes/actions-operator/blob/96fb0b07eb675f74cf1796be812bc7e67a0d62fc/src/bootstrap/index.ts#L151
+          sudo adduser $USER lxd
+          newgrp lxd
+          sudo lxd waitready
+          sudo lxd init --auto
+          sudo iptables -F FORWARD
+          sudo iptables -P FORWARD ACCEPT
+          sudo chmod a+wr /var/snap/lxd/common/lxd/unix.socket
+          sudo snap install charmcraft --classic
+      - name: Pack charm
+        id: pack
+        working-directory: ${{ inputs.path-to-charm-directory }}
+        run: charmcraft pack
+      - name: Upload charmcraft logs
+        if: ${{ failure() && steps.pack.outcome == 'failure' }}
+        uses: actions/upload-artifact@v3
+        with:
+          name: ${{ inputs.artifact-name }}-charmcraft-build-logs
+          path: ~/.local/state/charmcraft/log/
+          if-no-files-found: error
+      - name: Upload packed charm
+        uses: actions/upload-artifact@v3
+        with:
+          name: ${{ inputs.artifact-name }}
+          path: |
+            ${{ inputs.path-to-charm-directory }}/*.charm
+          if-no-files-found: error

.github/workflows/build_charms_with_cache.yaml

@@ -134,7 +134,7 @@ jobs:
         if: ${{ failure() && steps.pack.outcome == 'failure' }}
         uses: actions/upload-artifact@v3
         with:
-          name: ${{ inputs.artifact-name }}-charmcraft-logs
+          name: ${{ inputs.artifact-name }}-charmcraft-build-logs
           path: ~/.local/state/charmcraft/log/
           if-no-files-found: error
       - run: touch .empty

.github/workflows/release_charm.md

@@ -0,0 +1,32 @@
+Workflow file: [release_charm.yaml](release_charm.yaml)
+
+## Usage
+Add `.yaml` file to `.github/workflows/`
+```yaml
+# Copyright 2023 Canonical Ltd.
+# See LICENSE file for licensing details.
+name: Release to Charmhub
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    name: Build charm
+    uses: canonical/data-platform-workflows/.github/workflows/build_charm_without_cache.yaml@v2
+
+  release:
+    name: Release charm
+    needs:
+      - build
+    uses: canonical/data-platform-workflows/.github/workflows/release_charm.yaml@v2
+    with:
+      channel: latest/edge
+      artifact-name: ${{ needs.build.outputs.artifact-name }}
+    secrets:
+      charmhub-token: ${{ secrets.CHARMHUB_TOKEN }}
+    permissions:
+      contents: write  # Needed to create GitHub release
+```

.github/workflows/release_charm.yaml

@@ -0,0 +1,90 @@
+# Copyright 2023 Canonical Ltd.
+# See LICENSE file for licensing details.
+
+# Usage documentation: release_charm.md
+
+on:
+  workflow_call:
+    inputs:
+      channel:
+        description: Charmhub channel to release to
+        required: true
+        type: string
+      artifact-name:
+        description: Name of GitHub artifact that contains the .charm file(s) (use another workflow to build the charm)
+        required: true
+        type: string
+      path-to-charm-directory:
+        description: Relative path to charm directory (from GitHub artifact root)
+        default: .
+        type: string
+      create-github-release:
+        description: Create git tag & GitHub release
+        default: true
+        type: boolean
+    secrets:
+      charmhub-token:
+        description: Charmhub login token
+        required: true
+
+jobs:
+  get-workflow-version:
+    name: Get workflow version
+    uses: ./.github/workflows/_get_workflow_version.yaml
+    with:
+      repository-name: canonical/data-platform-workflows
+      file-name: release_charm.yaml
+
+  release-charm:
+    name: Release charm
+    needs:
+      - get-workflow-version
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - name: Install pyyaml
+        run: python3 -m pip install pyyaml
+      - name: Install docker
+        run: |
+          sudo adduser $USER docker
+          newgrp docker
+          sudo snap install docker
+      - name: Install charmcraft
+        run: sudo snap install charmcraft --classic
+      - name: Checkout caller repository
+        uses: actions/checkout@v3
+        with:
+          path: caller-repo
+      - name: Checkout release workflow repository
+        uses: actions/checkout@v3
+        with:
+          repository: canonical/data-platform-workflows
+          path: workflow-repo
+          ref: ${{ needs.get-workflow-version.outputs.version }}
+      - name: Download .charm file(s)
+        uses: actions/download-artifact@v3
+        with:
+          name: ${{ inputs.artifact-name }}
+          path: caller-repo
+      - name: Upload & release charm
+        id: release
+        working-directory: caller-repo
+        run: python3 ../workflow-repo/release_charm.py --charm-directory ${{ inputs.path-to-charm-directory }} --channel ${{ inputs.channel }}
+        env:
+          CHARMCRAFT_AUTH: ${{ secrets.charmhub-token }}
+      - name: Create GitHub release
+        if: ${{ inputs.create-github-release }}
+        working-directory: caller-repo
+        run: |
+          git tag ${{ steps.release.outputs.release_tag }}
+          git push origin ${{ steps.release.outputs.release_tag }}
+          gh release create ${{ steps.release.outputs.release_tag }} --verify-tag --generate-notes --title "${{ steps.release.outputs.release_title }}" --notes-file release_notes.txt
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Upload charmcraft logs
+        if: ${{ failure() && steps.release.outcome == 'failure' }}
+        uses: actions/upload-artifact@v3
+        with:
+          name: ${{ inputs.artifact-name }}-charmcraft-release-logs
+          path: ~/.local/state/charmcraft/log/
+          if-no-files-found: error

release_charm.py

@@ -0,0 +1,114 @@
+import argparse
+import dataclasses
+import json
+import logging
+import os
+import pathlib
+import subprocess
+import sys
+
+import yaml
+
+
+@dataclasses.dataclass
+class OCIResource:
+    """OCI image that has been uploaded to Charmhub as a charm resource"""
+
+    resource_name: str
+    revision: int
+
+
+def run(command_: list):
+    """Run subprocess command & log stderr
+
+    Returns:
+        stdout
+    """
+    process = subprocess.run(command_, capture_output=True, encoding="utf-8")
+    try:
+        process.check_returncode()
+    except subprocess.CalledProcessError as e:
+        logging.error(e.stderr)
+        raise
+    return process.stdout
+
+
+logging.basicConfig(level=logging.INFO, stream=sys.stdout)
+parser = argparse.ArgumentParser()
+parser.add_argument("--charm-directory")
+parser.add_argument("--channel")
+args = parser.parse_args()
+charm_directory = pathlib.Path(args.charm_directory)
+
+# Upload charm file(s) & store revision
+charm_revisions: list[int] = []
+for charm_file in charm_directory.glob("*.charm"):
+    logging.info(f"Uploading {charm_file=}")
+    output = run(["charmcraft", "upload", "--format", "json", charm_file])
+    revision: int = json.loads(output)["revision"]
+    logging.info(f"Uploaded charm {revision=}")
+    charm_revisions.append(revision)
+assert len(charm_revisions) > 0, "No .charm files found"
+
+metadata_file = yaml.safe_load((charm_directory / "metadata.yaml").read_text())
+charm_name = metadata_file["name"]
+
+# (Only for Kubernetes charms) upload OCI image(s) & store revision
+oci_resources: list[OCIResource] = []
+resources = metadata_file.get("resources", {})
+for resource_name, resource in resources.items():
+    if resource["type"] != "oci-image":
+        continue
+    image_name = resource["upstream-source"]
+    logging.info(f"Downloading OCI image: {image_name}")
+    run(["docker", "pull", image_name])
+    image_id = run(["docker", "image", "inspect", image_name, "--format", "'{{.Id}}'"])
+    image_id = image_id.rstrip("\n").strip("'").lstrip("sha256:")
+    assert "\n" not in image_id, f"Multiple local images found for {image_name}"
+    logging.info(f"Uploading charm resource: {resource_name}")
+    output = run(
+        [
+            "charmcraft",
+            "upload-resource",
+            "--format",
+            "json",
+            charm_name,
+            resource_name,
+            "--image",
+            image_id,
+        ]
+    )
+    revision: int = json.loads(output)["revision"]
+    logging.info(f"Uploaded charm resource {revision=}")
+    oci_resources.append(OCIResource(resource_name, revision))
+
+# Release charm file(s)
+for charm_revision in charm_revisions:
+    logging.info(f"Releasing {charm_revision=}")
+    command = [
+        "charmcraft",
+        "release",
+        charm_name,
+        "--revision",
+        str(charm_revision),
+        "--channel",
+        args.channel,
+    ]
+    for oci in oci_resources:
+        command += ["--resource", f"{oci.resource_name}:{oci.revision}"]
+    run(command)
+
+# Output GitHub release info
+release_tag = f"rev{max(charm_revisions)}"
+if len(charm_revisions) == 1:
+    release_title = "Revision "
+else:
+    release_title = "Revisions "
+release_title += ", ".join(str(revision) for revision in charm_revisions)
+release_notes = f"Released to {args.channel}\nOCI images:\n" + "\n".join(
+    f"- {dataclasses.asdict(oci)}" for oci in oci_resources
+)
+with open("release_notes.txt", "w") as file:
+    file.write(release_notes)
+with open(os.environ["GITHUB_OUTPUT"], "a") as file:
+    file.write(f"release_tag={release_tag}\nrelease_title={release_title}")