ci: add a github bot to support advanced PR review workflows

.github/workflows/bot.yml

@@ -0,0 +1,104 @@
+name: GitHub Bot
+
+on:
+  # Watch for changes on PR state, assignees, labels and head branch
+  pull_request:
+    types:
+      - assigned
+      - unassigned
+      - labeled
+      - unlabeled
+      - opened
+      - reopened
+      - synchronize # PR head updated
+
+  # Watch for changes on PR comment
+  issue_comment:
+    types: [created, edited, deleted]
+
+  # Manual run from GitHub Actions interface
+  workflow_dispatch:
+    inputs:
+      pull-request-list:
+        description: "PR(s) to process : specify 'all' or a comma separated list of PR numbers, e.g. '42,1337,7890'"
+        required: true
+        default: all
+        type: string
+
+jobs:
+  # This job creates a matrix of PR numbers based on the inputs from the various
+  # events that can trigger this workflow so that the process-pr job below can
+  # handle the parallel processing of the pull-requests
+  define-prs-matrix:
+    name: Define PRs matrix
+    # Prevent bot from retriggering itself
+    if: ${{ github.actor != vars.GH_BOT_LOGIN }}
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: read
+    outputs:
+      pr-numbers: ${{ steps.pr-numbers.outputs.pr-numbers }}
+
+    steps:
+      - name: Parse event inputs
+        id: pr-numbers
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          # Triggered by a workflow dispatch event
+          if [ '${{ github.event_name }}' = 'workflow_dispatch' ]; then
+            # If the input is 'all', create a matrix with every open PRs
+            if [ '${{ inputs.pull-request-list }}' = 'all' ]; then
+              pr_list=`gh pr list --state 'open' --repo '${{ github.repository }}' --json 'number' --template '{{$first := true}}{{range .}}{{if $first}}{{$first = false}}{{else}}, {{end}}{{"\""}}{{.number}}{{"\""}}{{end}}'`
+              [ -z "$pr_list" ] && echo 'Error : no opened PR found' >&2 && exit 1
+              echo "pr-numbers=[$pr_list]" >> "$GITHUB_OUTPUT"
+            # If the input is not 'all', test for each number in the comma separated
+            # list if the associated PR is opened, then add it to the matrix
+            else
+              pr_list_raw='${{ inputs.pull-request-list }}'
+              pr_list=''
+              IFS=','
+              for number in $pr_list; do
+                trimed=`echo "$number" | xargs`
+                pr_state=`gh pr view "$trimed" --repo '${{ github.repository }}' --json 'state' --template '{{.state}}' 2> /dev/null`
+                [ "$pr_state" != 'OPEN' ] && echo "Error : PR with number <$trimed> is not opened" >&2 && exit 1
+              done
+              echo "pr-numbers=[$pr_list]" >> "$GITHUB_OUTPUT"
+            fi
+          # Triggered by comment event, just add the associated PR number to the matrix
+          elif [ '${{ github.event_name }}' = 'issue_comment' ]; then
+            echo 'pr-numbers=["${{ github.event.issue.number }}"]' >> "$GITHUB_OUTPUT"
+          # Triggered by pull request event, just add the associated PR number to the matrix
+          elif [ '${{ github.event_name }}' = 'pull_request' ]; then
+            echo 'pr-numbers=["${{ github.event.pull_request.number }}"]' >> "$GITHUB_OUTPUT"
+          else
+            echo 'Error : unknown event ${{ github.event_name }}' >&2 && exit 1
+          fi
+
+  # This job processes each pull request in the matrix individually while ensuring
+  # that a same PR cannot be processed concurrently by mutliple runners
+  process-pr:
+    name: Process PR
+    needs: define-prs-matrix
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # Run one job for each PR to process
+        pr-number: ${{ fromJSON(needs.define-prs-matrix.outputs.pr-numbers) }}
+    concurrency:
+      # Prevent running concurrent jobs for a given PR number
+      group: ${{ matrix.pr-number }}
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Install Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Run GitHub Bot
+        env:
+          GITHUB_TOKEN: ${{ secrets.GH_BOT_PAT }}
+        run: go run . -pr-numbers '${{ matrix.pr-number }}' -verbose

contribs/github_bot/client/client.go

@@ -0,0 +1,235 @@
+package client
+
+import (
+	"bot/logger"
+	"bot/param"
+	"context"
+	"log"
+	"os"
+	"time"
+
+	"github.com/google/go-github/v66/github"
+)
+
+const PageSize = 100
+
+type GitHub struct {
+	Client *github.Client
+	Ctx    context.Context
+	DryRun bool
+	Logger logger.Logger
+	Owner  string
+	Repo   string
+}
+
+func (gh *GitHub) GetBotComment(prNum int) *github.IssueComment {
+	// List existing comments
+	var (
+		allComments []*github.IssueComment
+		sort        = "created"
+		direction   = "desc"
+		opts        = &github.IssueListCommentsOptions{
+			Sort:      &sort,
+			Direction: &direction,
+			ListOptions: github.ListOptions{
+				PerPage: PageSize,
+			},
+		}
+	)
+
+	for {
+		comments, response, err := gh.Client.Issues.ListComments(
+			gh.Ctx,
+			gh.Owner,
+			gh.Repo,
+			prNum,
+			opts,
+		)
+		if err != nil {
+			gh.Logger.Errorf("Unable to list comments for PR %d : %v", prNum, err)
+			return nil
+		}
+
+		allComments = append(allComments, comments...)
+
+		if response.NextPage == 0 {
+			break
+		}
+		opts.Page = response.NextPage
+	}
+
+	// Get current user (bot)
+	currentUser, _, err := gh.Client.Users.Get(gh.Ctx, "")
+	if err != nil {
+		gh.Logger.Errorf("Unable to get current user : %v", err)
+		return nil
+	}
+
+	// Get the comment created by current user
+	for _, comment := range allComments {
+		if comment.GetUser().GetLogin() == currentUser.GetLogin() {
+			return comment
+		}
+	}
+
+	return nil
+}
+
+func (gh *GitHub) SetBotComment(body string, prNum int) *github.IssueComment {
+	// Create bot comment if it not already exists
+	if comment := gh.GetBotComment(prNum); comment == nil {
+		newComment, _, err := gh.Client.Issues.CreateComment(
+			gh.Ctx,
+			gh.Owner,
+			gh.Repo,
+			prNum,
+			&github.IssueComment{Body: &body},
+		)
+		if err != nil {
+			gh.Logger.Errorf("Unable to create bot comment for PR %d : %v", prNum, err)
+			return nil
+		}
+		return newComment
+	} else {
+		comment.Body = &body
+		editComment, _, err := gh.Client.Issues.EditComment(
+			gh.Ctx,
+			gh.Owner,
+			gh.Repo,
+			comment.GetID(),
+			comment,
+		)
+		if err != nil {
+			gh.Logger.Errorf("Unable to edit bot comment with ID %d : %v", comment.GetID(), err)
+			return nil
+		}
+		return editComment
+	}
+}
+
+func (gh *GitHub) ListTeamMembers(team string) []*github.User {
+	var (
+		allMembers []*github.User
+		opts       = &github.TeamListTeamMembersOptions{
+			ListOptions: github.ListOptions{
+				PerPage: PageSize,
+			},
+		}
+	)
+
+	for {
+		members, response, err := gh.Client.Teams.ListTeamMembersBySlug(
+			gh.Ctx,
+			gh.Owner,
+			team,
+			opts,
+		)
+		if err != nil {
+			gh.Logger.Errorf("Unable to list members for team %s : %v", team, err)
+			return nil
+		}
+
+		allMembers = append(allMembers, members...)
+
+		if response.NextPage == 0 {
+			break
+		}
+		opts.Page = response.NextPage
+	}
+
+	return allMembers
+}
+
+func (gh *GitHub) ListPrReviewers(prNum int) *github.Reviewers {
+	var (
+		allReviewers = &github.Reviewers{}
+		opts         = &github.ListOptions{
+			PerPage: PageSize,
+		}
+	)
+
+	for {
+		reviewers, response, err := gh.Client.PullRequests.ListReviewers(
+			gh.Ctx,
+			gh.Owner,
+			gh.Repo,
+			prNum,
+			opts,
+		)
+		if err != nil {
+			gh.Logger.Errorf("Unable to list reviewers for PR %d : %v", prNum, err)
+			return nil
+		}
+
+		allReviewers.Teams = append(allReviewers.Teams, reviewers.Teams...)
+		allReviewers.Users = append(allReviewers.Users, reviewers.Users...)
+
+		if response.NextPage == 0 {
+			break
+		}
+		opts.Page = response.NextPage
+	}
+
+	return allReviewers
+}
+
+func (gh *GitHub) ListPrReviews(prNum int) []*github.PullRequestReview {
+	var (
+		allReviews []*github.PullRequestReview
+		opts       = &github.ListOptions{
+			PerPage: PageSize,
+		}
+	)
+
+	for {
+		reviews, response, err := gh.Client.PullRequests.ListReviews(
+			gh.Ctx,
+			gh.Owner,
+			gh.Repo,
+			prNum,
+			opts,
+		)
+		if err != nil {
+			gh.Logger.Errorf("Unable to list reviews for PR %d : %v", prNum, err)
+			return nil
+		}
+
+		allReviews = append(allReviews, reviews...)
+
+		if response.NextPage == 0 {
+			break
+		}
+		opts.Page = response.NextPage
+	}
+
+	return allReviews
+}
+
+func New(params param.Params) *GitHub {
+	gh := &GitHub{
+		Owner:  params.Owner,
+		Repo:   params.Repo,
+		DryRun: params.DryRun,
+	}
+
+	// This method will detect if the current process was launched by
+	// a GitHub Action or not and will accordingly return a logger suitable for
+	// the terminal output or for the GitHub Actions web interface
+	gh.Logger = logger.NewLogger(params.Verbose)
+
+	// Create context with timeout if specified in flags
+	if params.Timeout > 0 {
+		gh.Ctx, _ = context.WithTimeout(context.Background(), time.Duration(params.Timeout)*time.Millisecond)
+	} else {
+		gh.Ctx = context.Background()
+	}
+
+	// Init GitHub API Client using token from env
+	token, set := os.LookupEnv("GITHUB_TOKEN")
+	if !set {
+		log.Fatalf("GITHUB_TOKEN is not set in env")
+	}
+	gh.Client = github.NewClient(nil).WithAuthToken(token)
+
+	return gh
+}