feat: Automatic Release detection (#335)

Attempts to guess the release info, either by getting the last git
commit hash or by looking up some known environment variables that tracks
release identification.

client.go

@@ -208,7 +208,7 @@ func NewClient(options ClientOptions) (*Client, error) {
 	}
 
 	if options.Release == "" {
-		options.Release = os.Getenv("SENTRY_RELEASE")
+		options.Release = defaultRelease()
 	}
 
 	if options.Environment == "" {

client_test.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 	pkgErrors "github.com/pkg/errors"
 )
 
@@ -281,7 +282,8 @@ func TestCaptureEvent(t *testing.T) {
 		},
 	}
 	got := transport.lastEvent
-	if diff := cmp.Diff(want, got); diff != "" {
+	opts := cmp.Options{cmpopts.IgnoreFields(Event{}, "Release")}
+	if diff := cmp.Diff(want, got, opts); diff != "" {
 		t.Errorf("Event mismatch (-want +got):\n%s", diff)
 	}
 }

fasthttp/sentryfasthttp_test.go

@@ -206,7 +206,7 @@ func TestIntegration(t *testing.T) {
 		cmpopts.IgnoreFields(
 			sentry.Event{},
 			"Contexts", "EventID", "Extra", "Platform",
-			"Sdk", "ServerName", "Tags", "Timestamp",
+			"Release", "Sdk", "ServerName", "Tags", "Timestamp",
 		),
 		cmpopts.IgnoreMapEntries(func(k string, v string) bool {
 			// fasthttp changed Content-Length behavior in

http/sentryhttp_test.go

@@ -214,7 +214,7 @@ func TestIntegration(t *testing.T) {
 		cmpopts.IgnoreFields(
 			sentry.Event{},
 			"Contexts", "EventID", "Extra", "Platform",
-			"Sdk", "ServerName", "Tags", "Timestamp",
+			"Release", "Sdk", "ServerName", "Tags", "Timestamp",
 		),
 		cmpopts.IgnoreFields(
 			sentry.Request{},

tracing_test.go

@@ -151,7 +151,7 @@ func TestStartSpan(t *testing.T) {
 	opts := cmp.Options{
 		cmpopts.IgnoreFields(Event{},
 			"Contexts", "EventID", "Level", "Platform",
-			"Sdk", "ServerName",
+			"Release", "Sdk", "ServerName",
 		),
 		cmpopts.EquateEmpty(),
 	}
@@ -210,7 +210,7 @@ func TestStartChild(t *testing.T) {
 	opts := cmp.Options{
 		cmpopts.IgnoreFields(Event{},
 			"EventID", "Level", "Platform",
-			"Sdk", "ServerName", "Timestamp", "StartTime",
+			"Release", "Sdk", "ServerName", "Timestamp", "StartTime",
 		),
 		cmpopts.IgnoreMapEntries(func(k string, v interface{}) bool {
 			return k != "trace"

util.go

@@ -1,11 +1,14 @@
 package sentry
 
 import (
+	"bytes"
 	"crypto/rand"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"os"
+	"os/exec"
+	"strings"
 	"time"
 )
 
@@ -37,3 +40,43 @@ func prettyPrint(data interface{}) {
 	dbg, _ := json.MarshalIndent(data, "", "  ")
 	fmt.Println(string(dbg))
 }
+
+// attempts to guess a default release.
+func defaultRelease() string {
+	// Search environment variables (EV) known to hold release info.
+	envs := []string{
+		"SENTRY_RELEASE",
+		"HEROKU_SLUG_COMMIT",
+		"SOURCE_VERSION",
+		"CODEBUILD_RESOLVED_SOURCE_VERSION",
+		"CIRCLE_SHA1",
+		"GAE_DEPLOYMENT_ID",
+		"GITHUB_SHA",             // GitHub Actions - https://help.github.com/en/actions
+		"COMMIT_REF",             // Netlify - https://docs.netlify.com/
+		"VERCEL_GIT_COMMIT_SHA",  // Vercel - https://vercel.com/
+		"ZEIT_GITHUB_COMMIT_SHA", // Zeit (now known as Vercel)
+		"ZEIT_GITLAB_COMMIT_SHA",
+		"ZEIT_BITBUCKET_COMMIT_SHA"}
+	for _, e := range envs {
+		if val := os.Getenv(e); val != "" {
+			return val // Stop at first non-empty variable.
+		}
+	}
+
+	// No EV's, attempt to get the last commit hash with git.
+	var stdout bytes.Buffer
+	cmd := exec.Command("git", "rev-parse", "HEAD")
+	cmd.Stdout = &stdout
+	err := cmd.Run()
+	if err != nil {
+		Logger.Println("Failed attempt to run git rev-parse.")
+	} else {
+		shastr := strings.TrimSpace(stdout.String())
+		if len(shastr) == 40 { // sha1 hash length
+			return shastr
+		}
+	}
+
+	// Not able to find a release name at all.
+	return ""
+}