add a GH Actions workflow to check and see if any generated files need to be updated (#432)

* add a GH Actions workflow to check and see if any generated files need to be updated

* need protoc to run go generate

* looks like we do need to run with `sudo`

* also need `protoc-gen-go` binary

* pass the diff output as a file; it was too long for an env var

* pin protoc-gen-go@1.34.2

* fix version number

* don't care about exact protoc version & also don't fail the build

Author: drewda

.github/workflows/check-go-generate.yaml

@@ -0,0 +1,123 @@
+name: Check Generated Code
+
+on:
+  pull_request:
+    branches: [ main ]
+
+permissions:
+  pull-requests: write  # Needed for commenting on PRs
+  contents: read        # Needed for checking out code
+
+jobs:
+  check-generated:
+    name: Check Generated Code
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # Required for git diff to work properly
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.21'
+
+      - name: Install protoc and protoc-gen-go
+        run: |
+          sudo apt-get install -y protobuf-compiler
+          go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.34.2
+          echo "$(go env GOPATH)/bin" >> $GITHUB_PATH
+
+      - name: Run go generate
+        run: |
+          go generate ./...
+
+      - name: Check for changes
+        id: check_changes
+        run: |
+          # Create a temporary file for the diff, ignoring footer lines and protoc versions
+          git diff --ignore-matching-lines="Auto generated by spf13/cobra on" --ignore-matching-lines="protoc        v[0-9]" > changes.diff
+          
+          # Check if there are any changes
+          if [ -s changes.diff ]; then
+            echo "has_changes=true" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Comment on PR
+        uses: actions/github-script@v6
+        if: steps.check_changes.outputs.has_changes == 'true'
+        with:
+          script: |
+            // Find existing comment from this workflow
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+            });
+            
+            const existingComment = comments.find(comment => 
+              comment.user.login === 'github-actions[bot]' &&
+              comment.body.includes('## Generated Code Changes Required')
+            );
+            
+            // Read the diff file
+            const fs = require('fs');
+            const diff = fs.readFileSync('changes.diff', 'utf8');
+            
+            // Limit diff to 50,000 characters (leaving room for the rest of the comment)
+            const MAX_DIFF_LENGTH = 50000;
+            const isTruncated = diff.length > MAX_DIFF_LENGTH;
+            const truncatedDiff = isTruncated ? diff.substring(0, MAX_DIFF_LENGTH) + '\n... (diff truncated)' : diff;
+            
+            const body = '## Generated Code Changes Required\n\n' +
+              'The following files may need to be regenerated. Please run `go generate ./...` and commit the changes:\n\n' +
+              '```diff\n' +
+              truncatedDiff +
+              '\n```' +
+              (isTruncated ? '\n\n*Note: The diff has been truncated. Please run `go generate ./...` locally to see all changes.*' : '');
+            
+            if (existingComment) {
+              // Update existing comment
+              await github.rest.issues.updateComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                comment_id: existingComment.id,
+                body: body
+              });
+            } else {
+              // Create new comment
+              await github.rest.issues.createComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                issue_number: context.issue.number,
+                body: body
+              });
+            }
+
+      - name: Update success comment
+        uses: actions/github-script@v6
+        if: steps.check_changes.outputs.has_changes != 'true'
+        with:
+          script: |
+            // Find existing comment from this workflow
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+            });
+            
+            const existingComment = comments.find(comment => 
+              comment.user.login === 'github-actions[bot]' &&
+              comment.body.includes('## Generated Code Changes Required')
+            );
+            
+            if (existingComment) {
+              // Update existing comment to show success
+              await github.rest.issues.updateComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                comment_id: existingComment.id,
+                body: '## Generated Code Check ✅\n\nAll generated code is up to date.'
+              });
+            }