From a18733683031726549922e040a5b40edbef7284f Mon Sep 17 00:00:00 2001
From: Roman Khimov <roman@nspcc.ru>
Date: Thu, 25 Jun 2020 19:31:45 +0300
Subject: [PATCH] rpc/server: fix error reporting in Start

This error message makes no sense when shutting down the server:
2020-06-25T19:29:53.251+0300    ERROR   failed to start RPC server      {"error": "http: Server closed"}

And ListenAndServer is documented to always return non-nil error one of which
is http.ErrServerClosed. This should also fix the following test failure:

==================
WARNING: DATA RACE
Read at 0x00c000254243 by goroutine 49:
  testing.(*common).logDepth()
      /usr/local/go/src/testing/testing.go:665 +0xa1
  testing.(*common).Logf()
      /usr/local/go/src/testing/testing.go:658 +0x8f
  testing.(*T).Logf()
      <autogenerated>:1 +0x75
  go.uber.org/zap/zaptest.testingWriter.Write()
      /go/pkg/mod/go.uber.org/zap@v1.10.0/zaptest/logger.go:130 +0x11f
  go.uber.org/zap/zaptest.(*testingWriter).Write()
      <autogenerated>:1 +0xa9
  go.uber.org/zap/zapcore.(*ioCore).Write()
      /go/pkg/mod/go.uber.org/zap@v1.10.0/zapcore/core.go:90 +0x1c3
  go.uber.org/zap/zapcore.(*CheckedEntry).Write()
      /go/pkg/mod/go.uber.org/zap@v1.10.0/zapcore/entry.go:215 +0x1e7
  go.uber.org/zap.(*Logger).Error()
      /go/pkg/mod/go.uber.org/zap@v1.10.0/logger.go:203 +0x95
  github.com/nspcc-dev/neo-go/pkg/rpc/server.(*Server).Start()
      /go/src/github.com/nspcc-dev/neo-go/pkg/rpc/server/server.go:179 +0x5c5

Previous write at 0x00c000254243 by goroutine 44:
  testing.tRunner.func1()
      /usr/local/go/src/testing/testing.go:900 +0x353
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:913 +0x1bb

Goroutine 49 (running) created at:
  github.com/nspcc-dev/neo-go/pkg/rpc/server.initClearServerWithInMemoryChain()
      /go/src/github.com/nspcc-dev/neo-go/pkg/rpc/server/server_helper_test.go:69 +0x305
  github.com/nspcc-dev/neo-go/pkg/rpc/server.initServerWithInMemoryChain()
      /go/src/github.com/nspcc-dev/neo-go/pkg/rpc/server/server_helper_test.go:78 +0x3c
  github.com/nspcc-dev/neo-go/pkg/rpc/server.testRPCProtocol()
      /go/src/github.com/nspcc-dev/neo-go/pkg/rpc/server/server_test.go:805 +0x53
  github.com/nspcc-dev/neo-go/pkg/rpc/server.TestRPC.func1()
      /go/src/github.com/nspcc-dev/neo-go/pkg/rpc/server/server_test.go:793 +0x44
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:909 +0x199

Goroutine 44 (finished) created at:
  testing.(*T).Run()
      /usr/local/go/src/testing/testing.go:960 +0x651
  github.com/nspcc-dev/neo-go/pkg/rpc/server.TestRPC()
      /go/src/github.com/nspcc-dev/neo-go/pkg/rpc/server/server_test.go:792 +0x5d
  testing.tRunner()
      /usr/local/go/src/testing/testing.go:909 +0x199
==================
---
 pkg/rpc/server/server.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/pkg/rpc/server/server.go b/pkg/rpc/server/server.go
index 613a73345..d9299574d 100644
--- a/pkg/rpc/server/server.go
+++ b/pkg/rpc/server/server.go
@@ -168,17 +168,17 @@ func (s *Server) Start(errChan chan error) {
 		s.log.Info("starting rpc-server (https)", zap.String("endpoint", s.https.Addr))
 		go func() {
 			err := s.https.ListenAndServeTLS(cfg.CertFile, cfg.KeyFile)
-			if err != nil {
+			if err != http.ErrServerClosed {
 				s.log.Error("failed to start TLS RPC server", zap.Error(err))
+				errChan <- err
 			}
-			errChan <- err
 		}()
 	}
 	err := s.ListenAndServe()
-	if err != nil {
+	if err != http.ErrServerClosed {
 		s.log.Error("failed to start RPC server", zap.Error(err))
+		errChan <- err
 	}
-	errChan <- err
 }
 
 // Shutdown overrides the http.Server Shutdown