Send CID for sentry events. (dgraph-io#5625)

Author: parasssh

dgraph/cmd/alpha/run.go

@@ -709,5 +709,6 @@ func run() {
 	adminCloser.SignalAndWait()
 	glog.Info("Disposing server state.")
 	worker.State.Dispose()
+	x.RemoveCidFile()
 	glog.Infoln("Server shutdown. Bye!")
 }

dgraph/cmd/zero/raft.go

@@ -508,6 +508,7 @@ func (n *node) initAndStartNode() error {
 				err := n.proposeAndWait(context.Background(), &pb.ZeroProposal{Cid: id})
 				if err == nil {
 					glog.Infof("CID set for cluster: %v", id)
+					x.WriteCidFile(id)
 					break
 				}
 				if err == errInvalidProposal {

dgraph/cmd/zero/run.go

@@ -303,6 +303,8 @@ func run() {
 		store.Closer.SignalAndWait()
 		// Stop all internal requests.
 		_ = grpcListener.Close()
+
+		x.RemoveCidFile()
 	}()
 
 	glog.Infoln("Running Dgraph Zero...")

worker/groups.go

@@ -811,6 +811,7 @@ START:
 			}
 			if i == 0 {
 				glog.Infof("Received first state update from Zero: %+v", state)
+				x.WriteCidFile(state.Cid)
 			}
 			select {
 			case stateCh <- state:

x/sentry_integration.go

@@ -18,6 +18,7 @@ package x
 
 import (
 	"errors"
+	"io/ioutil"
 	"os"
 	"strings"
 	"time"
@@ -28,8 +29,9 @@ import (
 )
 
 var (
-	env string
-	dsn string // API KEY to use
+	env     string
+	dsn     string // API KEY to use
+	cidPath string
 )
 
 // Sentry API KEYs to use.
@@ -99,6 +101,41 @@ func ConfigureSentryScope(subcmd string) {
 		scope.SetTag("dgraph", subcmd)
 		scope.SetLevel(sentry.LevelFatal)
 	})
+
+	// e.g. /tmp/dgraph-alpha-cid-sentry
+	cidPath = os.TempDir() + "/" + "dgraph-" + subcmd + "-cid-sentry"
+}
+
+// WriteCidFile writes the CID to a well-known location so it can be read and
+// sent to Sentry on panic.
+func WriteCidFile(cid string) {
+	if cid == "" {
+		return
+	}
+	if err := ioutil.WriteFile(cidPath, []byte(cid), 0644); err != nil {
+		glog.Warningf("unable to write CID to file %v %v", cidPath, err)
+		return
+	}
+}
+
+// readAndRemoveCidFile reads the file from a well-known location so
+// it can be read and sent to Sentry on panic.
+func readAndRemoveCidFile() string {
+	cid, err := ioutil.ReadFile(cidPath)
+	if err != nil {
+		glog.Warningf("unable to read CID from file %v %v. Skip", cidPath, err)
+		return ""
+	}
+	RemoveCidFile()
+	return string(cid)
+}
+
+// RemoveCidFile removes the file.
+func RemoveCidFile() {
+	if err := os.RemoveAll(cidPath); err != nil {
+		glog.Warningf("unable to remove the CID file at %v %v. Skip", cidPath, err)
+		return
+	}
 }
 
 // CaptureSentryException sends the error report to Sentry.
@@ -111,6 +148,12 @@ func CaptureSentryException(err error) {
 // PanicHandler is the callback function when a panic happens. It does not recover and is
 // only used to log panics (in our case send an event to sentry).
 func PanicHandler(out string) {
+	if cid := readAndRemoveCidFile(); cid != "" {
+		// re-configure sentry scope to include cid if found.
+		sentry.ConfigureScope(func(scope *sentry.Scope) {
+			scope.SetTag("CID", cid)
+		})
+	}
 	// Output contains the full output (including stack traces) of the panic.
 	sentry.CaptureException(errors.New(out))
 	FlushSentry() // Need to flush asap. Don't defer here.
@@ -119,7 +162,6 @@ func PanicHandler(out string) {
 }
 
 // WrapPanics is a wrapper on panics. We use it to send sentry events about panics
-// and crash right after.
 func WrapPanics() {
 	exitStatus, err := panicwrap.BasicWrap(PanicHandler)
 	if err != nil {