Fix Windows build of Jaeger tests (open-telemetry#1577)

* Fix Windows build of Jaeger tests

The Jaeger tests use the low-level syscall package. The Windows specific
function called in that package has a different function signature than
the unix version. Add a windows specific file using the build flags to
isolate this OS specific functionality.

* Add changes to changelog

* Blind succeed to account for unimplemented functionality on Windows

CHANGELOG.md

@@ -35,6 +35,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Fixed
 
 - The sequential timing check of timestamps in the stdout exporter are now setup explicitly to be sequential (#1571). (#1572)
+- Windows build of Jaeger tests now compiles with OS specific functions (#1576). (#1577)
 
 ## [0.17.0] - 2020-02-12
 

exporters/trace/jaeger/assertsocketbuffersize.go

@@ -0,0 +1,48 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !windows
+
+package jaeger
+
+import (
+	"net"
+	"runtime"
+	"syscall"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func assertSockBufferSize(t *testing.T, expectedBytes int, conn *net.UDPConn) bool {
+	fd, err := conn.File()
+	if !assert.NoError(t, err) {
+		return false
+	}
+
+	bufferBytes, err := syscall.GetsockoptInt(int(fd.Fd()), syscall.SOL_SOCKET, syscall.SO_SNDBUF)
+	if !assert.NoError(t, err) {
+		return false
+	}
+
+	// The linux kernel doubles SO_SNDBUF value (to allow space for
+	// bookkeeping overhead) when it is set using setsockopt(2), and this
+	// doubled value is returned by getsockopt(2)
+	// https://linux.die.net/man/7/socket
+	if runtime.GOOS == "linux" {
+		return assert.GreaterOrEqual(t, expectedBytes*2, bufferBytes)
+	}
+
+	return assert.Equal(t, expectedBytes, bufferBytes)
+}

exporters/trace/jaeger/assertsocketbuffersize_windows.go

@@ -0,0 +1,34 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build windows
+
+package jaeger
+
+import (
+	"net"
+	"testing"
+)
+
+func assertSockBufferSize(t *testing.T, expectedBytes int, conn *net.UDPConn) bool {
+	// The Windows implementation of the net.UDPConn does not implement the
+	// functionality to return a file handle, instead a "not supported" error
+	// is returned:
+	//
+	// https://github.com/golang/go/blob/6cc8aa7ece96aca282db19f08aa5c98ed13695d9/src/net/fd_windows.go#L175-L178
+	//
+	// This means we are not able to pass the connection to a syscall and
+	// determine the buffer size.
+	return true
+}

exporters/trace/jaeger/reconnecting_udp_client_test.go

@@ -18,8 +18,6 @@ import (
 	"fmt"
 	"math/rand"
 	"net"
-	"runtime"
-	"syscall"
 	"testing"
 	"time"
 
@@ -82,19 +80,6 @@ func newUDPConn() (net.PacketConn, *net.UDPConn, error) {
 	return mockServer, conn, nil
 }
 
-func assertSockBufferSize(t *testing.T, expectedBytes int, conn *net.UDPConn) bool {
-	fd, _ := conn.File()
-	bufferBytes, _ := syscall.GetsockoptInt(int(fd.Fd()), syscall.SOL_SOCKET, syscall.SO_SNDBUF)
-
-	// The linux kernel doubles SO_SNDBUF value (to allow space for bookkeeping overhead) when it is set using setsockopt(2), and this doubled value is returned by getsockopt(2)
-	// https://linux.die.net/man/7/socket
-	if runtime.GOOS == "linux" {
-		return assert.GreaterOrEqual(t, expectedBytes*2, bufferBytes)
-	}
-
-	return assert.Equal(t, expectedBytes, bufferBytes)
-}
-
 func assertConnWritable(t *testing.T, conn udpConn, serverConn net.PacketConn) {
 	expectedString := "yo this is a test"
 	_, err := conn.Write([]byte(expectedString))