trigger-argo-workflows: Add PR information as labels

actions/trigger-argo-workflow/action.yaml

@@ -58,6 +58,7 @@ runs:
       with:
         repository: ${{ env.action_repo }}
         ref: ${{ env.action_ref }}
+        path: ".actions/shared-workflows"
 
     - name: Restore cache
       id: restore
@@ -102,12 +103,12 @@ runs:
       with:
         check-latest: true
         cache-dependency-path: |
-          actions/trigger-argo-workflow/go.sum
-        go-version-file: "actions/trigger-argo-workflow/go.mod"
+          .actions/shared-workflows/actions/trigger-argo-workflow/go.sum
+        go-version-file: ".actions/shared-workflows/actions/trigger-argo-workflow/go.mod"
 
     - name: Get Argo Token
       id: get-argo-token
-      uses: "./actions/get-vault-secrets"
+      uses: "./.actions/shared-workflows/actions/get-vault-secrets"
       with:
         vault_instance: ${{ inputs.instance }}
         repo_secrets: |
@@ -117,7 +118,7 @@ runs:
       id: run
       shell: bash
       run: |
-        cd actions/trigger-argo-workflow
+        cd .actions/shared-workflows/actions/trigger-argo-workflow
 
         # Split the parameters into an array and pass them to the action as --parameter PARAM
         while read -r line; do
@@ -141,3 +142,4 @@ runs:
           ${{ inputs.extra_args }}
       env:
         ARGO_TOKEN: ${{ env.ARGO_TOKEN }}
+        GITHUB_TOKEN: ${{ github.token }}

actions/trigger-argo-workflow/cmd/trigger-argo-workflow/argo.go

@@ -72,8 +72,8 @@ func (a App) outputWithURI(input *bytes.Buffer) (string, string) {
 	return uri, output
 }
 
-func (a App) runCmd(md GitHubActionsMetadata) (string, string, error) {
-	args := a.args(md)
+func (a App) runCmd(labelProviders ...LabelsProvider) (string, string, error) {
+	args := a.args(labelProviders...)
 
 	cmd := exec.Command("argo", args...)
 	cmdOutput := &bytes.Buffer{}
@@ -125,15 +125,15 @@ func (a *App) openGitHubOutput() io.WriteCloser {
 	return f
 }
 
-func (a *App) Run(md GitHubActionsMetadata) error {
+func (a *App) Run(labelProviders ...LabelsProvider) error {
 	bo := backoff.WithMaxRetries(backoff.NewExponentialBackOff(), a.retries)
 
 	var uri string
 	var out string
 
 	run := func() error {
 		var err error
-		uri, out, err = a.runCmd(md)
+		uri, out, err = a.runCmd(labelProviders...)
 
 		return err
 	}

actions/trigger-argo-workflow/cmd/trigger-argo-workflow/argoflags.go

@@ -1,10 +1,18 @@
 package main
 
 import (
+	"context"
+	"errors"
 	"fmt"
+	"log/slog"
+	"os"
+	"os/exec"
 	"regexp"
+	"strconv"
 	"strings"
+	"time"
 
+	"github.com/google/go-github/v60/github"
 	"github.com/kelseyhightower/envconfig"
 )
 
@@ -33,12 +41,140 @@ func (r *RepoInfo) Decode(text string) error {
 	return nil
 }
 
-func (r RepoInfo) ToArgs() string {
-	return fmt.Sprintf(
-		"trigger-repo-name=%s,trigger-repo-owner=%s",
-		r.Name,
-		r.Owner,
-	)
+func (r RepoInfo) ToLabels() []string {
+	return []string{
+		fmt.Sprintf("trigger-repo-name=%s", r.Name),
+		fmt.Sprintf("trigger-repo-owner=%s", r.Owner),
+	}
+}
+
+// PullRequestInfo represents collected information about the pull request this
+// action was executed in.
+type PullRequestInfo struct {
+	Number      int
+	CreatedAt   *time.Time
+	FirstCommit *github.RepositoryCommit
+}
+
+func (pri *PullRequestInfo) ToLabels() []string {
+	if pri == nil {
+		return []string{}
+	}
+	result := []string{
+		fmt.Sprintf("trigger-pr=%d", pri.Number),
+	}
+	if pri.CreatedAt != nil {
+		result = append(result, fmt.Sprintf("trigger-pr-created-at=%d", pri.CreatedAt.UTC().Unix()))
+	}
+	if pri.FirstCommit != nil && pri.FirstCommit.Commit != nil && pri.FirstCommit.Commit.Committer != nil {
+		result = append(result, fmt.Sprintf("trigger-pr-first-commit-date=%d", pri.FirstCommit.Commit.Committer.Date.UTC().Unix()))
+	}
+	return result
+}
+
+var errPRLookupNotSupported error = errors.New("PR lookup not supported")
+
+func getPullRequestNumberFromHead(ctx context.Context, logger *slog.Logger, workdir string) (int64, error) {
+	ref := os.Getenv("GITHUB_SHA")
+	if ref == "" || len(ref) < 40 {
+		ref = "HEAD"
+	}
+	l := logger.With(slog.String("workdir", workdir), slog.String("ref", ref))
+	l.InfoContext(ctx, "checking PR information in commit")
+	gitPath, err := exec.LookPath("git")
+	if err != nil {
+		return -1, errPRLookupNotSupported
+	}
+	cmd := exec.CommandContext(ctx, gitPath, "log", "--pretty=%s", "-1", ref)
+	cmd.Dir = workdir
+	raw, err := cmd.CombinedOutput()
+	if err != nil {
+		return -1, err
+	}
+	output := strings.TrimSpace(string(raw))
+	re := regexp.MustCompile(`^.*\(#([0-9]+)\)$`)
+	match := re.FindStringSubmatch(output)
+	if len(match) < 2 {
+		l.WarnContext(ctx, "unsupported commit message", slog.String("msg", output))
+		return -1, nil
+	}
+	return strconv.ParseInt(match[1], 10, 64)
+}
+
+// NewPullRequestInfo tries to generate a new PullRequestInfo object based on
+// information available inside the GitHub API and environment variables. If
+// no PR information is available, nil is returned without an error!
+func NewPullRequestInfo(ctx context.Context, logger *slog.Logger, gh *github.Client) (*PullRequestInfo, error) {
+	var err error
+	var number int64
+	ref := os.Getenv("GITHUB_REF")
+	re := regexp.MustCompile(`^refs/pull/([0-9]+)/merge$`)
+	match := re.FindStringSubmatch(ref)
+	if len(match) == 0 {
+		// This is happening outside of a pull request. This means that we
+		// cannot simply get the pull request number from the ref and need to
+		// look somewhere else. For our purposes we can also take a look at the
+		// HEAD commit message and continue from there.
+		workdir := os.Getenv("GITHUB_WORKSPACE")
+		if workdir == "" {
+			workdir = "."
+		}
+		number, err = getPullRequestNumberFromHead(ctx, logger, workdir)
+		if err != nil {
+			if err == errPRLookupNotSupported {
+				logger.InfoContext(ctx, "PR Git lookup not supported")
+				return nil, nil
+			}
+			return nil, err
+		}
+		if number == -1 {
+			logger.InfoContext(ctx, "PR Git lookup found no PR")
+			return nil, nil
+		}
+	} else {
+		number, err = strconv.ParseInt(match[1], 10, 32)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse PR number: %w", err)
+		}
+	}
+	info := PullRequestInfo{
+		Number: int(number),
+	}
+
+	repo := &RepoInfo{}
+	if err := repo.Decode(os.Getenv("GITHUB_REPOSITORY")); err != nil {
+		return nil, err
+	}
+	pr, _, err := gh.PullRequests.Get(ctx, repo.Owner, repo.Name, info.Number)
+	if err != nil {
+		return nil, err
+	}
+	if pr.CreatedAt != nil {
+		info.CreatedAt = &pr.CreatedAt.Time
+	}
+
+	// Now let's also try to retrieve the first commit in this PR:
+	opts := github.ListOptions{
+		Page: 1,
+	}
+	var firstCommit *github.RepositoryCommit
+	for {
+		commits, resp, err := gh.PullRequests.ListCommits(ctx, repo.Owner, repo.Name, info.Number, &opts)
+		if err != nil {
+			return nil, err
+		}
+		if resp.NextPage <= opts.Page {
+			if len(commits) > 0 {
+				firstCommit = commits[len(commits)-1]
+			}
+			break
+		}
+		opts.Page = resp.NextPage
+	}
+	if firstCommit != nil {
+		info.FirstCommit = firstCommit
+	}
+	return &info, nil
 }
 
 // GitHubActionsMetadata contains the metadata provided by GitHub Actions in
@@ -60,31 +196,41 @@ func NewGitHubActionsMetadata() (GitHubActionsMetadata, error) {
 	return m, nil
 }
 
-func (m GitHubActionsMetadata) ToArgs() []string {
+func (m GitHubActionsMetadata) ToLabels() []string {
 	var z GitHubActionsMetadata
 	if m == z {
 		return []string{}
 	}
 
-	return []string{
-		"--labels",
-		strings.Join([]string{
-			fmt.Sprintf("trigger-build-number=%s", m.BuildNumber),
-			fmt.Sprintf("trigger-commit=%s", m.Commit),
-			fmt.Sprintf("trigger-commit-author=%s", m.CommitAuthor),
-			m.Repo.ToArgs(),
-			fmt.Sprintf("trigger-event=%s", m.BuildEvent),
-		}, ","),
+	repoLabels := m.Repo.ToLabels()
+
+	result := []string{
+		fmt.Sprintf("trigger-build-number=%s", m.BuildNumber),
+		fmt.Sprintf("trigger-commit=%s", m.Commit),
+		fmt.Sprintf("trigger-commit-author=%s", m.CommitAuthor),
+		fmt.Sprintf("trigger-event=%s", m.BuildEvent),
 	}
+	return append(result, repoLabels...)
+}
+
+type LabelsProvider interface {
+	ToLabels() []string
 }
 
-func (a App) args(m GitHubActionsMetadata) []string {
+func (a App) args(providers ...LabelsProvider) []string {
 	// Force the labels when the command is `submit`
 	addCILabels := a.addCILabels || a.command == "submit"
 
 	var args []string
 	if addCILabels {
-		args = m.ToArgs()
+		var labels []string
+		for _, prov := range providers {
+			if prov == nil {
+				continue
+			}
+			labels = append(labels, prov.ToLabels()...)
+		}
+		args = append(args, "--labels", strings.Join(labels, ","))
 	}
 
 	if a.workflowTemplate != "" {