From e3be0be247114f5b77d5a8ec66f4067b74fc83e1 Mon Sep 17 00:00:00 2001
From: Sridhar Seshasayee <sseshasa@redhat.com>
Date: Tue, 24 Jul 2018 12:15:31 +0530
Subject: [PATCH] Pass original context to trace calls across grpc nodes in
 step functions.

Pass the original context to the runStepOn() function so that it can be
used by the opensensus grpc plugin to trace the calls on other nodes in
the gluster cluster. Also, append the requestID to the span info in
addition to the associated function name so that the operation can be
identified on the tracing UI application.

Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>
---
 glusterd2/transaction/rpc-client.go  | 4 ++--
 glusterd2/transaction/rpc-service.go | 8 ++++++++
 glusterd2/transaction/step.go        | 2 +-
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/glusterd2/transaction/rpc-client.go b/glusterd2/transaction/rpc-client.go
index 5a5b8a2d0..373ac901c 100644
--- a/glusterd2/transaction/rpc-client.go
+++ b/glusterd2/transaction/rpc-client.go
@@ -16,7 +16,7 @@ import (
 )
 
 // runStepOn will run the step on the specified node
-func runStepOn(step string, node uuid.UUID, c TxnCtx) error {
+func runStepOn(origCtx netctx.Context, step string, node uuid.UUID, c TxnCtx) error {
 	// TODO: I'm creating connections on demand. This should be changed so that
 	// we have long term connections.
 	p, err := peer.GetPeerF(node.String())
@@ -73,7 +73,7 @@ func runStepOn(step string, node uuid.UUID, c TxnCtx) error {
 
 	var rsp *TxnStepResp
 
-	rsp, err = client.RunStep(netctx.TODO(), req)
+	rsp, err = client.RunStep(origCtx, req)
 	if err != nil {
 		logger.WithFields(log.Fields{
 			"error": err,
diff --git a/glusterd2/transaction/rpc-service.go b/glusterd2/transaction/rpc-service.go
index e040d7d98..bec886871 100644
--- a/glusterd2/transaction/rpc-service.go
+++ b/glusterd2/transaction/rpc-service.go
@@ -7,6 +7,7 @@ import (
 	"github.com/gluster/glusterd2/glusterd2/servers/peerrpc"
 
 	log "github.com/sirupsen/logrus"
+	"go.opencensus.io/trace"
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
 )
@@ -37,6 +38,13 @@ func (p *txnSvc) RunStep(rpcCtx context.Context, req *TxnStepReq) (*TxnStepResp,
 	logger = ctx.Logger().WithField("stepfunc", req.StepFunc)
 	logger.Debug("RunStep request received")
 
+	if rpcCtx != nil {
+		reqID := ctx.GetTxnReqID()
+		spanName := req.StepFunc + " ReqID:" + reqID
+		_, span := trace.StartSpan(rpcCtx, spanName)
+		defer span.End()
+	}
+
 	f, ok = getStepFunc(req.StepFunc)
 	if !ok {
 		err = errors.New("step function not found in registry")
diff --git a/glusterd2/transaction/step.go b/glusterd2/transaction/step.go
index 2c8246c94..da2441377 100644
--- a/glusterd2/transaction/step.go
+++ b/glusterd2/transaction/step.go
@@ -139,7 +139,7 @@ func runStepFuncOnNode(origCtx context.Context, stepName string, ctx TxnCtx, nod
 		err = runStepFuncLocally(origCtx, stepName, ctx)
 	} else {
 		// remote node
-		err = runStepOn(stepName, node, ctx)
+		err = runStepOn(origCtx, stepName, node, ctx)
 	}
 
 	respCh <- stepPeerResp{node, err}