Release task and instructions

.github/workflows/release.yml

@@ -0,0 +1,100 @@
+name: release
+
+# Allow the action to be triggered manually in the "actions"
+# tab of GitHub.
+on:
+  workflow_dispatch
+
+jobs:
+    release:
+        name: Package, Publish, and Register
+        runs-on:
+            - ubuntu-latest
+        steps:
+            # Needed to get the buildpack code
+            - name: Checkout
+              uses: actions/checkout@v3
+
+            # Install musl gcc needed to compile rust buildpack
+            # to linux musl target
+            - name: Install musl-tools
+              run: sudo apt-get install musl-tools --no-install-recommends
+
+            # Get the `pack` command for packaging the buildpack
+            - id: setup-pack
+              name: Install Pack
+              uses: buildpacks/github-actions/setup-pack@v4.6.0
+
+            # Used by `pack buildpack package --publish`. The buildpack
+            # will be published to this user and password
+            - name: Login to Docker Hub
+              uses: docker/login-action@v1
+              with:
+                registry: docker.io
+                username: ${{ secrets.DOCKER_HUB_USER }}
+                password: ${{ secrets.DOCKER_HUB_PASS }}
+
+            # Most of the time this will be a no-op, since GitHub releases new images every week
+            # which include the latest stable release of Rust, Rustup, Clippy and rustfmt.
+            - name: Update Rust toolchain
+              run: rustup update
+            - name: Rust Cache
+              uses: Swatinem/rust-cache@v1.3.0
+
+            # Needed to get `cargo libcnb package` command
+            - name: Install libcnb plugin
+              run: cargo install libcnb-cargo
+            # Configure Rust so it knows how to compile to the linux musl target
+            - name: Install Rust linux-musl target
+              run: rustup target add x86_64-unknown-linux-musl
+            # Compile the rust buildpack
+            - id: package-libcnb-rs
+              run: cargo libcnb package --release
+
+            # Pull out data from the buildpacks `buildpack.toml` to make
+            # it available to other commands. Also package and publish
+            # the buildpack to docker hub as well as generate a local
+            # file containing the buildpack.
+            - id: package
+              run: |
+                #!/usr/bin/env bash
+                set -euo pipefail
+                BP_ID="$(cat buildpack.toml | yj -t | jq -r .buildpack.id)"
+                VERSION="$(cat buildpack.toml | yj -t | jq -r .buildpack.version)"
+                ESCAPED_ID="$(echo "$BP_ID" | sed 's/\//_/g')"
+                PACKAGE="${REPO}"
+
+                # --publish pushes to the registry (logged in)
+                pack buildpack package --publish --path "target/buildpack/release/$ESCAPED_ID" "${PACKAGE}:${VERSION}"
+                pack buildpack package --format file  --path "target/buildpack/release/$ESCAPED_ID" "${ESCAPED_ID}_${VERSION}.cnb"
+
+                DIGEST="$(crane digest ${PACKAGE}:${VERSION})"
+                echo "::set-output name=bp_id::$BP_ID"
+                echo "::set-output name=version::$VERSION"
+                echo "::set-output name=address::${PACKAGE}@${DIGEST}"
+                echo "::set-output name=package::${ESCAPED_ID}_${VERSION}.cnb"
+              env:
+                REPO: docker.io/heroku/procfile-cnb
+
+            # Open a PR to the buildpack registry index.
+            # For example: https://github.com/buildpacks/registry-index/issues/2776
+            - id: register
+              uses: docker://ghcr.io/buildpacks/actions/registry/request-add-entry:4.2.0
+              with:
+                token:   ${{ secrets.PUBLIC_REPO_TOKEN }}
+                id:      ${{ steps.package.outputs.bp_id }}
+                version: ${{ steps.package.outputs.version }}
+                address: ${{ steps.package.outputs.address }}
+
+            # Create a release and tag on the github repo
+            # For example: https://github.com/heroku/procfile-cnb/releases/tag/0.7.1
+            # Attaches the previously generate cloud native buildpack file (`*.cnb`)
+            # to the release
+            - id: release
+              name: Upload buildpackage to release
+              uses: svenstaro/upload-release-action@v2
+              with:
+                repo_token: ${{ secrets.GITHUB_TOKEN }}
+                file: ${{ steps.package.outputs.package }}
+                tag: ${{ steps.package.outputs.version }}
+                overwrite: true

README.md

@@ -7,6 +7,23 @@ This is a [Cloud Native Buildpack](https://buildpacks.io/) that replicates the b
 
 It is written in Rust using the Cloud Native Buildpack framework [libcnb.rs](https://github.com/Malax/libcnb.rs).
 
+## Deployment
+
+### 1) Generate a release
+
+- Visit the actions page https://github.com/heroku/procfile-cnb/actions,
+- Click on "release" and then "Run workflow".
+
+When the action is successful a release will be added to https://github.com/heroku/procfile-cnb/releases and docker hub https://hub.docker.com/r/heroku/procfile-cnb/tags.
+
+### 2) Update pack images
+
+- Clone https://github.com/heroku/pack-images
+- Edit the `uri` in all builder-*.toml files to point at the latest docker hub release for `heroku/procfile` under `buildpacks`.
+- Edit the `version` in all builder-*.toml files to the latest version of `heroku/procfile` for each `order.group`.
+- Commit and make a PR to pack images
+- Fix any CI errors and merge on success
+
 ## Development
 
 ### Prerequisites