CLI: enable homebrew installer

The dist docs for for the `homebrew` installer indicate there are two
parts to this:

1. create a "tap" repo and a github token for dist to use to manage it
2. configure dist here (with the token as a secret)

The first piece will need to be done by someone else.
This diff does the 2nd piece.

The config for dist targets the extant `svix/homebrew-svix` repo, which
appears to be where the tap lived previously.
It's not clear if we'd need to empty that repo, reboot it, or anything
else.

Refs:
- https://opensource.axo.dev/cargo-dist/book/installers/homebrew.html
- https://github.com/svix/homebrew-svix

.github/workflows/release.yml

@@ -276,14 +276,60 @@ jobs:
 
           gh release edit "${{ needs.plan.outputs.tag }}" --target "$RELEASE_COMMIT" $PRERELEASE_FLAG --draft=false
 
+  publish-homebrew-formula:
+    needs:
+      - plan
+      - host
+    runs-on: "ubuntu-20.04"
+    env:
+      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      PLAN: ${{ needs.plan.outputs.val }}
+      GITHUB_USER: "axo bot"
+      GITHUB_EMAIL: "[email protected]"
+    if: ${{ !fromJson(needs.plan.outputs.val).announcement_is_prerelease || fromJson(needs.plan.outputs.val).publish_prereleases }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          repository: "svix/homebrew-svix"
+          token: ${{ secrets.HOMEBREW_TAP_TOKEN }}
+      # So we have access to the formula
+      - name: Fetch homebrew formulae
+        uses: actions/download-artifact@v4
+        with:
+          pattern: artifacts-*
+          path: Formula/
+          merge-multiple: true
+      # This is extra complex because you can make your Formula name not match your app name
+      # so we need to find releases with a *.rb file, and publish with that filename.
+      - name: Commit formula files
+        run: |
+          git config --global user.name "${GITHUB_USER}"
+          git config --global user.email "${GITHUB_EMAIL}"
+
+          for release in $(echo "$PLAN" | jq --compact-output '.releases[] | select([.artifacts[] | endswith(".rb")] | any)'); do
+            filename=$(echo "$release" | jq '.artifacts[] | select(endswith(".rb"))' --raw-output)
+            name=$(echo "$filename" | sed "s/\.rb$//")
+            version=$(echo "$release" | jq .app_version --raw-output)
+
+            export PATH="/home/linuxbrew/.linuxbrew/bin:$PATH"
+            brew update
+            # We avoid reformatting user-provided data such as the app description and homepage.
+            brew style --except-cops FormulaAudit/Homepage,FormulaAudit/Desc,FormulaAuditStrict --fix "Formula/${filename}" || true
+
+            git add "Formula/${filename}"
+            git commit -m "${name} ${version}"
+          done
+          git push
+
   announce:
     needs:
       - plan
       - host
+      - publish-homebrew-formula
     # use "always() && ..." to allow us to wait for all publish jobs while
     # still allowing individual publish jobs to skip themselves (for prereleases).
     # "host" however must run to completion, no skipping allowed!
-    if: ${{ always() && needs.host.result == 'success' }}
+    if: ${{ always() && needs.host.result == 'success' && (needs.publish-homebrew-formula.result == 'skipped' || needs.publish-homebrew-formula.result == 'success') }}
     runs-on: "ubuntu-20.04"
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

dist-workspace.toml

@@ -8,7 +8,7 @@ cargo-dist-version = "0.28.0"
 # CI backends to support
 ci = "github"
 # The installers to generate for each app
-installers = ["shell", "powershell", "msi"]
+installers = ["shell", "powershell", "homebrew", "msi"]
 # Target platforms to build apps for (Rust target-triple syntax)
 targets = ["aarch64-apple-darwin", "aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-musl", "x86_64-pc-windows-msvc"]
 # Whether dist should create a Github Release or use an existing draft
@@ -19,4 +19,8 @@ install-path = "~/.svix/bin"
 install-updater = true
 # Whether CI should trigger releases with dispatches instead of tag pushes
 dispatch-releases = true
+# A GitHub repo to push Homebrew formulas to
+tap = "svix/homebrew-svix"
+# Publish jobs to run in CI
+publish-jobs = ["homebrew"]