feat: automate updating homebrew tap formula (#9412)

.github/workflows/release.yaml

@@ -328,11 +328,85 @@ jobs:
           event-type: coder-release
           client-payload: '{"coder_version": "${{ steps.version.outputs.version }}"}'
 
+  publish-homebrew:
+    name: Publish to Homebrew tap
+    runs-on: ubuntu-latest
+    needs: release
+    if: ${{ !inputs.dry_run }}
+
+    steps:
+      # TODO: skip this if it's not a new release (i.e. a backport). This is
+      #       fine right now because it just makes a PR that we can close.
+      - name: Update homebrew
+        env:
+          # Variables used by the `gh` command
+          GH_REPO: coder/homebrew-coder
+          GH_TOKEN: ${{ secrets.CDRCI_GITHUB_TOKEN }}
+        run: |
+          # Keep version number around for reference, removing any potential leading v
+          coder_version="$(echo "${{ needs.release.outputs.version }}" | tr -d v)"
+
+          set -euxo pipefail
+
+          # Setup Git
+          git config --global user.email "ci@coder.com"
+          git config --global user.name "Coder CI"
+          git config --global credential.helper "store"
+
+          temp_dir="$(mktemp -d)"
+          cd "$temp_dir"
+
+          # Download checksums
+          checksums_url="$(gh release view --repo coder/coder v2.1.4 --json assets \
+            | jq -r ".assets | map(.url) | .[]" \
+            | grep -e ".checksums.txt\$")"
+          wget "$checksums_url" -O checksums.txt
+
+          # Get the SHAs
+          darwin_arm_sha="$(cat checksums.txt | grep "darwin_arm64.zip" | awk '{ print $1 }')"
+          darwin_intel_sha="$(cat checksums.txt | grep "darwin_amd64.zip" | awk '{ print $1 }')"
+          linux_sha="$(cat checksums.txt | grep "linux_amd64.tar.gz" | awk '{ print $1 }')"
+
+          echo "macOS arm64: $darwin_arm_sha"
+          echo "macOS amd64: $darwin_intel_sha"
+          echo "Linux amd64: $linux_sha"
+
+          # Check out the homebrew repo
+          git clone "https://github.com/$GH_REPO" homebrew-coder
+          brew_branch="auto-release/$coder_version"
+          cd homebrew-coder
+
+          # Check if a PR already exists.
+          pr_count="$(gh pr list --search "head:$brew_branch" --json id,closed | jq -r ".[] | select(.closed == false) | .id" | wc -l)"
+          if [[ "$pr_count" > 0 ]]; then
+            echo "Bailing out as PR already exists" 2>&1
+            exit 0
+          fi
+
+          # Set up cdrci credentials for pushing to homebrew-coder
+          echo "https://x-access-token:$GH_TOKEN@github.com" >> ~/.git-credentials
+          # Update the formulae and push
+          git checkout -b "$brew_branch"
+          ./scripts/update-v2.sh "$coder_version" "$darwin_arm_sha" "$darwin_intel_sha" "$linux_sha"
+          git add .
+          git commit -m "coder $coder_version"
+          git push -u origin -f "$brew_branch"
+
+          # Create PR
+          gh pr create \
+            -B master -H "$brew_branch" \
+            -t "coder $coder_version" \
+            -b "" \
+            -r "${{ github.actor }}" \
+            -a "${{ github.actor }}" \
+            -b "This automatic PR was triggered by the release of Coder v$coder_version"
+
   publish-winget:
     name: Publish to winget-pkgs
     runs-on: windows-latest
     needs: release
     if: ${{ !inputs.dry_run }}
+
     steps:
       - name: Checkout
         uses: actions/checkout@v3
@@ -412,6 +486,7 @@ jobs:
     runs-on: windows-latest
     needs: release
     if: ${{ !inputs.dry_run }}
+
     steps:
       - name: Checkout
         uses: actions/checkout@v3