Get commit message and branch from CI if unavailable (#2062)

* Get commit message and branch from CI if unavailable

* Add tests

cmd/util.go

@@ -385,6 +385,11 @@ func addGitHubMetadataToEnvironment(repo *git.Repository, env map[string]string)
 }
 
 func addGitCommitMetadata(repo *git.Repository, repoRoot string, m *backend.UpdateMetadata) error {
+	// When running in a CI/CD environment, the current git repo may be running from a
+	// detached HEAD and may not have have the latest commit message. We fall back to
+	// CI-system specific environment variables when possible.
+	ciVars := ciutil.DetectVars()
+
 	// Commit at HEAD
 	head, err := repo.Head()
 	if err != nil {
@@ -398,15 +403,23 @@ func addGitCommitMetadata(repo *git.Repository, repoRoot string, m *backend.Upda
 		return errors.Wrap(commitErr, "getting HEAD commit info")
 	}
 
+	// If in detached head, will be "HEAD", and fallback to use value from CI/CD system if possible.
+	// Otherwise, the value will be like "refs/heads/master".
 	headName := head.Name().String()
-	// Ignore when in detached HEAD state, should be "re"
+	if headName == "HEAD" && ciVars.BranchName != "" {
+		headName = ciVars.BranchName
+	}
 	if headName != "HEAD" {
-		m.Environment[backend.GitHeadName] = head.Name().String()
+		m.Environment[backend.GitHeadName] = headName
 	}
 
-	// If there is no message set manually, default to the Git title.
+	// If there is no message set manually, default to the Git commit's title.
+	msg := commit.Message
+	if msg == "" && ciVars.CommitMessage != "" {
+		msg = ciVars.CommitMessage
+	}
 	if m.Message == "" {
-		m.Message = gitCommitTitle(commit.Message)
+		m.Message = gitCommitTitle(msg)
 	}
 
 	// Store committer and author information.

cmd/util_test.go

@@ -14,6 +14,7 @@
 package cmd
 
 import (
+	"os"
 	"testing"
 
 	"github.com/pulumi/pulumi/pkg/backend"
@@ -35,6 +36,13 @@ func assertEnvValue(t *testing.T, md *backend.UpdateMetadata, key, val string) {
 // TestReadingGitRepo tests the functions which read data fom the local Git repo
 // to add metadata to any updates.
 func TestReadingGitRepo(t *testing.T) {
+	// Disable our CI/CD detection code, since if this unit test is ran under CI
+	// it will change the expected behavior.
+	os.Setenv("PULUMI_DISABLE_CI_DETECTION", "1")
+	defer func() {
+		os.Unsetenv("PULUMI_DISABLE_CI_DETECTION")
+	}()
+
 	e := pul_testing.NewEnvironment(t)
 	defer e.DeleteIfNotFailed()
 
@@ -134,7 +142,7 @@ func TestReadingGitRepo(t *testing.T) {
 		assertEnvValue(t, test, backend.GitHeadName, "refs/heads/feature/branch2")
 	}
 
-	// Change refs by checkingout a tagged commit.
+	// Change refs by checking out a tagged commit.
 	// But since we'll be in a detached HEAD state, the git.headName isn't provided.
 	e.RunCommand("git", "checkout", "v0.0.0")
 
@@ -146,4 +154,36 @@ func TestReadingGitRepo(t *testing.T) {
 		_, ok := test.Environment[backend.GitHeadName]
 		assert.False(t, ok, "Expected no 'git.headName' key, since in detached head state.")
 	}
+
+	// Confirm that data can be inferred from the CI system if unavailable.
+	// Fake running under Travis CI.
+	varsToSave := []string{"TRAVIS", "TRAVIS_BRANCH"}
+	origEnvVars := make(map[string]string)
+	for _, varName := range varsToSave {
+		origEnvVars[varName] = os.Getenv(varName)
+	}
+	defer func() {
+		for _, varName := range varsToSave {
+			orig := origEnvVars[varName]
+			if orig == "" {
+				os.Unsetenv(varName)
+			} else {
+				os.Setenv(varName, orig)
+			}
+		}
+	}()
+
+	os.Unsetenv("PULUMI_DISABLE_CI_DETECTION") // Restore our CI/CD detection logic.
+	os.Setenv("TRAVIS", "1")
+	os.Setenv("TRAVIS_BRANCH", "branch-from-ci")
+
+	{
+		test := &backend.UpdateMetadata{
+			Environment: make(map[string]string),
+		}
+		assert.NoError(t, addGitMetadata(e.RootPath, test))
+		name, ok := test.Environment[backend.GitHeadName]
+		assert.True(t, ok, "Expected 'git.headName' key, from CI util.")
+		assert.Equal(t, "branch-from-ci", name)
+	}
 }

pkg/util/ciutil/detect.go

@@ -88,6 +88,11 @@ func IsCI() bool {
 // DetectSystem returns a CI system name when the current system looks like a CI system. Detection is based on
 // environment variables that CI vendors we know about set.
 func DetectSystem() System {
+	// Provide a way to disable CI/CD detection, as it can interfere with the ability to test.
+	if os.Getenv("PULUMI_DISABLE_CI_DETECTION") != "" {
+		return ""
+	}
+
 	for sys, d := range detectors {
 		if d.IsCI() {
 			return sys

pkg/util/ciutil/vars.go

@@ -30,6 +30,10 @@ type Vars struct {
 	BuildURL string
 	// SHA is the SHA hash of the code repo at which this build/job is running.
 	SHA string
+	// BranchName is the name of the feature branch currently being built.
+	BranchName string
+	// CommitMessage is the full message of the Git commit being built.
+	CommitMessage string
 }
 
 // DetectVars detects and returns the CI variables for the current environment.
@@ -44,12 +48,16 @@ func DetectVars() Vars {
 		v.BuildID = os.Getenv("CI_JOB_ID")
 		v.BuildURL = os.Getenv("CI_JOB_URL")
 		v.SHA = os.Getenv("CI_COMMIT_SHA")
+		v.BranchName = os.Getenv("CI_COMMIT_REF_NAME")
+		v.CommitMessage = os.Getenv("CI_COMMIT_MESSAGE")
 	case Travis:
 		// We are running in Travis. See https://docs.travis-ci.com/user/environment-variables/. Travis doesn't
 		// set a build URL in its environment -- see  https://github.com/travis-ci/travis-ci/issues/8935.
 		v.BuildID = os.Getenv("TRAVIS_JOB_ID")
 		v.BuildType = os.Getenv("TRAVIS_EVENT_TYPE")
 		v.SHA = os.Getenv("TRAVIS_PULL_REQUEST_SHA")
+		v.BranchName = os.Getenv("TRAVIS_BRANCH")
+		v.CommitMessage = os.Getenv("TRAVIS_COMMIT_MESSAGE")
 	}
 	return v
 }