From 965427d491affd40360517b8fa12dd76a380f285 Mon Sep 17 00:00:00 2001
From: Abhishek Pandey <abhishek@alcion.ai>
Date: Tue, 16 May 2023 13:37:52 -0700
Subject: [PATCH] Place concurrency limiter middleware after retry middlewares
 (#3420)

This is to safeguard against the scenario where retry handlers might spawn additional requests to graph. Such retries may cause us to exceed concurrent request limits, leading to 429s ( `Application is over its MailboxConcurrency limit`)

This PR will ensure that such retry requests are also funneled through the concurrency limiter.

---

#### Does this PR need a docs update or release note?

- [ ] :white_check_mark: Yes, it's included
- [ ] :clock1: Yes, but in a later PR
- [x] :no_entry: No

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] :sunflower: Feature
- [x] :bug: Bugfix
- [ ] :world_map: Documentation
- [ ] :robot: Supportability/Tests
- [ ] :computer: CI/Deployment
- [ ] :broom: Tech Debt/Cleanup

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

#### Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] :muscle: Manual
- [x] :zap: Unit test
- [ ] :green_heart: E2E
---
 src/internal/connector/graph/service.go | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/internal/connector/graph/service.go b/src/internal/connector/graph/service.go
index dc5129ac4..f0aa71f08 100644
--- a/src/internal/connector/graph/service.go
+++ b/src/internal/connector/graph/service.go
@@ -247,11 +247,6 @@ func kiotaMiddlewares(
 ) []khttp.Middleware {
 	mw := []khttp.Middleware{}
 
-	// Optionally add concurrency limiter middleware if it has been initialized
-	if concurrencyLim != nil {
-		mw = append(mw, concurrencyLim)
-	}
-
 	mw = append(mw, []khttp.Middleware{
 		msgraphgocore.NewGraphTelemetryHandler(options),
 		&RetryMiddleware{
@@ -264,10 +259,18 @@ func kiotaMiddlewares(
 		khttp.NewParametersNameDecodingHandler(),
 		khttp.NewUserAgentHandler(),
 		&LoggingMiddleware{},
-		&RateLimiterMiddleware{},
-		&MetricsMiddleware{},
 	}...)
 
+	// Optionally add concurrency limiter middleware if it has been initialized.
+	if concurrencyLim != nil {
+		mw = append(mw, concurrencyLim)
+	}
+
+	mw = append(
+		mw,
+		&RateLimiterMiddleware{},
+		&MetricsMiddleware{})
+
 	if len(cc.appendMiddleware) > 0 {
 		mw = append(mw, cc.appendMiddleware...)
 	}