feat: charmcraft pack action

.github/workflows/test-charmcraft.yml

@@ -0,0 +1,68 @@
+name: Test Charmcraft
+
+on:
+  pull_request:
+    paths:
+      - ".github/workflows/*charmcraft*"
+      - "charmcraft**"
+  push:
+    branches:
+      - main
+
+jobs:
+  test-install-success:
+    strategy:
+      matrix:
+        channel: [latest/stable, latest/edge, 2.x/stable]
+        include:
+          - channel: ''
+            revision: 5303
+          - channel: latest/stable
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./charmcraft/setup
+        id: setup
+        with:
+          channel: ${{ matrix.channel }}
+          revision: ${{ matrix.revision }}
+      - name: Check revision number if set with a revision
+        if: matrix.revision != ''
+        run: |
+          [[ ${{ matrix.revision }} == ${{ steps.setup.outputs.charmcraft-revision }} ]]
+      - name: Check that revisions are set
+        run: |
+          test ${{ steps.setup.outputs.charmcraft-revision }} -ge 0
+          test ${{ steps.setup.outputs.lxd-revision }} -ge 0
+      - name: Check that install works even if Charmcraft is already installed
+        uses: ./charmcraft/setup
+  test-pack:
+    strategy:
+      matrix:
+        os: [ubuntu-22.04, ubuntu-24.04]
+        channel: [latest/stable]
+        include:
+          - os: ubuntu-24.04
+            channel: ''
+            revision: 5303
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/checkout@v4
+        with:
+          repository: juju/juju
+          path: juju
+          ref: main
+      - name: Pack charm
+        id: charmcraft
+        uses: ./charmcraft/pack
+        with:
+          path: juju/testcharms/charms/lxd-profile/
+          channel: ${{ matrix.channel }}
+          revision: ${{ matrix.revision }}
+      - name: Upload charm
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-charm-${{ matrix.os }}-${{ steps.charmcraft.outputs.charmcraft-revision }}
+          path: juju/testcharms/charms/lxd-profile/*.charm
+

.github/workflows/test.yml

@@ -54,4 +54,4 @@ jobs:
       uses: actions/upload-artifact@v3
       with:
         name: test-rock_${{ matrix.os }}
-        path: ${{ steps.rockcraft.outputs.rock }}
+        path: ${{ steps.rockcraft.outputs.rock }}

charmcraft/pack/action.yaml

@@ -0,0 +1,64 @@
+name: "Build a charm"
+description: "Pack a charm with Charmcraft"
+author: "Canonical"
+inputs:
+  path:
+    description: >
+      The location of the Charmcraft project.
+
+      Defaults to the base of the repository.
+    default: '.'
+  verbosity:
+    description: >
+      Set the build verbosity level to 'quiet', 'brief', 'verbose', 'debug' or
+      'trace'.
+
+      The default is 'trace'.
+    default: 'trace'
+  channel:
+    description: >
+      Install the snap from a specific channel
+
+      If not provided, it defaults to stable.
+    default: 'stable'
+  revision:
+    description: >
+      Pin the snap revision to install.
+
+      If not provided, it defaults to whatever revision is in latest/stable.
+    default: ''
+outputs:
+  charms:
+    description: The names of any charm files created.
+    value: ${{ steps.pack-charm.outputs.charms }}
+  charmcraft-revision:
+    description: The revision of Charmcraft used for the pack.
+    value: ${{ steps.setup.outputs.charmcraft-revision }}
+  lxd-revision:
+    description: The revision of lxd used for the pack.
+    value: ${{ steps.setup.outputs.lxd-revision }}
+runs:
+  using: 'composite'
+  steps:
+    - uses: ./charmcraft/setup
+      id: setup
+      with:
+        channel: ${{ inputs.channel }}
+        revision: ${{ inputs.revision }}
+    - uses: actions/cache@v4
+      with:
+        path: ~/snap/charmcraft/common/cache
+        key: charmcraft-cache-${{ hashfiles('**/requirements.txt', '**/*.lock', '**/charmcraft.yaml') }}
+        restore-keys: |
+          charmcraft-cache-
+    - id: pack-charm
+      shell: bash
+      env:
+        CRAFT_VERBOSITY_LEVEL: ${{ inputs.verbosity }}
+      working-directory: ${{ inputs.path }}
+      run: |
+        charmcraft pack
+        echo "charms=$(ls -1 *.charm | tr '\n' ' ')" >> "$GITHUB_OUTPUT"
+branding:
+  icon: layers
+  color: orange

charmcraft/setup/action.yaml

@@ -0,0 +1,69 @@
+name: "Setup Charmcraft"
+description: "Install Charmcraft"
+author: "Canonical"
+inputs:
+  channel:
+    description: >
+      Install the snap from a specific channel
+
+      If not provided, it defaults to stable.
+    default: 'stable'
+  revision:
+    description: >
+      Pin the snap revision to install.
+
+      If not provided, it defaults to whatever revision is in latest/stable.
+    default: ''
+  lxd-channel:
+    description: >
+      The LXD channel to use.
+
+      Defaults to the recommended channel for Charmcraft.
+    default: 5.21/stable
+outputs:
+  lxd-revision:
+    description: The LXD revision used.
+    value: ${{ steps.install.outputs.lxd }}
+  charmcraft-revision:
+    description: The Charmcraft revision used.
+    value: ${{ steps.install.outputs.charmcraft }}
+runs:
+  using: 'composite'
+  steps:
+    - shell: bash
+      name: Check system compatibility
+      run: |
+        if [[ $(uname -s) != Linux ]]; then
+          echo "::error::This action only works on Linux runners."
+          exit 1
+        fi
+        if ! which snap; then
+          echo "::error::This action requires snapd"
+        fi
+    - uses: canonical/setup-lxd@main
+      with:
+        channel: ${{ inputs.lxd-channel }}
+    - shell: bash
+      working-directory: ${{ inputs.path }}
+      name: Install Charmcraft
+      id: install
+      run: |
+        if [ -x /snap/bin/charmcraft ]; then
+          action=refresh
+        else
+          action=install
+        fi
+        if [ -n "${{ inputs.revision }}" ]; then
+          echo "::notice::Using Charmcraft revision ${{ inputs.revision }}"
+          sudo snap $action --revision=${{ inputs.revision }} --classic charmcraft
+        else
+          echo "::notice::Using Charmcraft from channel ${{ inputs.channel }}"
+          sudo snap $action --channel=${{ inputs.channel }} --classic charmcraft
+        fi
+
+
+        echo "lxd=$(curl -sS --unix-socket /run/snapd.socket http://localhost/v2/snaps/lxd -X GET | jq -r .result.revision)" >> "$GITHUB_OUTPUT"
+        echo "charmcraft=$(curl -sS --unix-socket /run/snapd.socket http://localhost/v2/snaps/charmcraft -X GET | jq -r .result.revision)" >> "$GITHUB_OUTPUT"
+branding:
+  icon: package
+  color: orange

rockcraft-pack/action.yml

@@ -4,8 +4,8 @@ author: "Canonical"
 inputs:
   path:
     description: >
-      The location of the Rockcraft project. 
-      
+      The location of the Rockcraft project.
+
       Defaults to the base of the repository.
     default: '.'
   verbosity: