Logging interface

README.md

@@ -204,6 +204,31 @@ func init() {
 }
 ```
 
+**Logger**
+
+xray uses an interface for its logger:
+
+```go
+type Logger interface {
+  Log(level LogLevel, msg fmt.Stringer)
+}
+
+const (
+  LogLevelDebug LogLevel = iota + 1
+  LogLevelInfo
+  LogLevelWarn
+  LogLevelError
+)
+```
+
+The default logger logs to stdout at "info" and above. To change the logger, call `xray.SetLogger(myLogger)`. There is a default logger implementation that writes to an `io.Writer` from a specified minimum log level. For example, to log to stderr at "error" and above:
+
+```go
+xray.SetLogger(xraylog.NewDefaultLogger(os.Stderr, xraylog.LogLevelError))
+```
+
+Note that the `xray.Config{}` fields `LogLevel` and `LogFormat` are deprecated and no longer have any effect.
+
 ## License
 
 The AWS X-Ray SDK for Go is licensed under the Apache 2.0 License. See LICENSE and NOTICE.txt for more information.

awsplugins/beanstalk/beanstalk.go

@@ -12,8 +12,8 @@ import (
 	"encoding/json"
 	"io/ioutil"
 
+	"github.com/aws/aws-xray-sdk-go/internal/logger"
 	"github.com/aws/aws-xray-sdk-go/internal/plugins"
-	log "github.com/cihub/seelog"
 )
 
 const Origin = "AWS::ElasticBeanstalk::Environment"
@@ -29,14 +29,14 @@ func addPluginMetadata(pluginmd *plugins.PluginMetadata) {
 
 	rawConfig, err := ioutil.ReadFile(ebConfigPath)
 	if err != nil {
-		log.Errorf("Unable to read Elastic Beanstalk configuration file %s: %v", ebConfigPath, err)
+		logger.Errorf("Unable to read Elastic Beanstalk configuration file %s: %v", ebConfigPath, err)
 		return
 	}
 
 	config := &plugins.BeanstalkMetadata{}
 	err = json.Unmarshal(rawConfig, config)
 	if err != nil {
-		log.Errorf("Unable to unmarshal Elastic Beanstalk configuration file %s: %v", ebConfigPath, err)
+		logger.Errorf("Unable to unmarshal Elastic Beanstalk configuration file %s: %v", ebConfigPath, err)
 		return
 	}
 

awsplugins/ec2/ec2.go

@@ -11,8 +11,8 @@ package ec2
 import (
 	"github.com/aws/aws-sdk-go/aws/ec2metadata"
 	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-xray-sdk-go/internal/logger"
 	"github.com/aws/aws-xray-sdk-go/internal/plugins"
-	log "github.com/cihub/seelog"
 )
 
 const Origin = "AWS::EC2::Instance"
@@ -26,13 +26,13 @@ func Init() {
 func addPluginMetadata(pluginmd *plugins.PluginMetadata) {
 	session, e := session.NewSession()
 	if e != nil {
-		log.Errorf("Unable to create a new ec2 session: %v", e)
+		logger.Errorf("Unable to create a new ec2 session: %v", e)
 		return
 	}
 	client := ec2metadata.New(session)
 	doc, err := client.GetInstanceIdentityDocument()
 	if err != nil {
-		log.Errorf("Unable to read EC2 instance metadata: %v", err)
+		logger.Errorf("Unable to read EC2 instance metadata: %v", err)
 		return
 	}
 

awsplugins/ecs/ecs.go

@@ -11,8 +11,8 @@ package ecs
 import (
 	"os"
 
+	"github.com/aws/aws-xray-sdk-go/internal/logger"
 	"github.com/aws/aws-xray-sdk-go/internal/plugins"
-	log "github.com/cihub/seelog"
 )
 
 const Origin = "AWS::ECS::Container"
@@ -27,7 +27,7 @@ func addPluginMetadata(pluginmd *plugins.PluginMetadata) {
 	hostname, err := os.Hostname()
 
 	if err != nil {
-		log.Errorf("Unable to retrieve hostname from OS. %v", err)
+		logger.Errorf("Unable to retrieve hostname from OS. %v", err)
 		return
 	}
 

daemoncfg/daemon_config.go

@@ -13,8 +13,7 @@ import (
 	"strconv"
 	"strings"
 
-	log "github.com/cihub/seelog"
-
+	"github.com/aws/aws-xray-sdk-go/internal/logger"
 	"github.com/pkg/errors"
 )
 
@@ -69,7 +68,7 @@ func GetDaemonEndpointsFromString(dAddr string) (*DaemonEndpoints, error) {
 	// Try to get the X-Ray daemon address from an environment variable
 	if envDaemonAddr := os.Getenv("AWS_XRAY_DAEMON_ADDRESS"); envDaemonAddr != "" {
 		daemonAddr = envDaemonAddr
-		log.Infof("using daemon endpoints from environment variable AWS_XRAY_DAEMON_ADDRESS: %v", envDaemonAddr)
+		logger.Infof("using daemon endpoints from environment variable AWS_XRAY_DAEMON_ADDRESS: %v", envDaemonAddr)
 	} else if dAddr != "" {
 		daemonAddr = dAddr
 	}
@@ -85,12 +84,9 @@ func resolveAddress(dAddr string) (*DaemonEndpoints, error) {
 		return parseSingleForm(addr[0])
 	} else if len(addr) == 2 {
 		return parseDoubleForm(addr)
-
 	} else {
 		return nil, errors.New("invalid daemon address: " + dAddr)
 	}
-
-	return nil, nil
 }
 
 func parseDoubleForm(addr []string) (*DaemonEndpoints, error) {

internal/logger/logger.go

@@ -0,0 +1,78 @@
+// Copyright 2017-2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with the License. A copy of the License is located at
+//
+//     http://aws.amazon.com/apache2.0/
+//
+// or in the "license" file accompanying this file. This file 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.
+
+package logger
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/aws/aws-xray-sdk-go/xraylog"
+)
+
+// This internal pacakge hides the actual logging functions from the user.
+
+// The Logger instance used by xray to log. Set via xray.SetLogger().
+var Logger xraylog.Logger = xraylog.NewDefaultLogger(os.Stdout, xraylog.LogLevelInfo)
+
+func Debugf(format string, args ...interface{}) {
+	Logger.Log(xraylog.LogLevelDebug, printfArgs{format, args})
+}
+
+func Debug(args ...interface{}) {
+	Logger.Log(xraylog.LogLevelDebug, printArgs(args))
+}
+
+func DebugDeferred(fn func() string) {
+	Logger.Log(xraylog.LogLevelDebug, stringerFunc(fn))
+}
+
+func Infof(format string, args ...interface{}) {
+	Logger.Log(xraylog.LogLevelInfo, printfArgs{format, args})
+}
+
+func Info(args ...interface{}) {
+	Logger.Log(xraylog.LogLevelInfo, printArgs(args))
+}
+
+func Warnf(format string, args ...interface{}) {
+	Logger.Log(xraylog.LogLevelWarn, printfArgs{format, args})
+}
+
+func Warn(args ...interface{}) {
+	Logger.Log(xraylog.LogLevelWarn, printArgs(args))
+}
+
+func Errorf(format string, args ...interface{}) {
+	Logger.Log(xraylog.LogLevelError, printfArgs{format, args})
+}
+
+func Error(args ...interface{}) {
+	Logger.Log(xraylog.LogLevelError, printArgs(args))
+}
+
+type printfArgs struct {
+	format string
+	args   []interface{}
+}
+
+func (p printfArgs) String() string {
+	return fmt.Sprintf(p.format, p.args...)
+}
+
+type printArgs []interface{}
+
+func (p printArgs) String() string {
+	return fmt.Sprint([]interface{}(p)...)
+}
+
+type stringerFunc func() string
+
+func (sf stringerFunc) String() string {
+	return sf()
+}

internal/logger/logger_test.go

@@ -0,0 +1,83 @@
+// Copyright 2017-2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with the License. A copy of the License is located at
+//
+//     http://aws.amazon.com/apache2.0/
+//
+// or in the "license" file accompanying this file. This file 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.
+
+package logger
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/aws/aws-xray-sdk-go/xraylog"
+)
+
+func TestLogger(t *testing.T) {
+	oldLogger := Logger
+	defer func() { Logger = oldLogger }()
+
+	var buf bytes.Buffer
+
+	// filter properly by level
+	Logger = xraylog.NewDefaultLogger(&buf, xraylog.LogLevelWarn)
+
+	Debug("debug")
+	Info("info")
+	Warn("warn")
+	Error("error")
+
+	gotLines := strings.Split(strings.TrimSpace(buf.String()), "\n")
+	if len(gotLines) != 2 {
+		t.Fatalf("got %d lines", len(gotLines))
+	}
+
+	if !strings.Contains(gotLines[0], "[WARN] warn") {
+		t.Error("expected first line to be warn")
+	}
+
+	if !strings.Contains(gotLines[1], "[ERROR] error") {
+		t.Error("expected second line to be warn")
+	}
+}
+
+func TestDeferredDebug(t *testing.T) {
+	oldLogger := Logger
+	defer func() { Logger = oldLogger }()
+
+	var buf bytes.Buffer
+
+	Logger = xraylog.NewDefaultLogger(&buf, xraylog.LogLevelInfo)
+
+	var called bool
+	DebugDeferred(func() string {
+		called = true
+		return "deferred"
+	})
+
+	if called {
+		t.Error("deferred should not have been called")
+	}
+
+	if buf.String() != "" {
+		t.Errorf("unexpected log contents: %s", buf.String())
+	}
+
+	Logger = xraylog.NewDefaultLogger(&buf, xraylog.LogLevelDebug)
+
+	DebugDeferred(func() string {
+		called = true
+		return "deferred"
+	})
+
+	if !called {
+		t.Error("deferred should have been called")
+	}
+
+	if !strings.Contains(buf.String(), "[DEBUG] deferred") {
+		t.Errorf("expected deferred message, got %s", buf.String())
+	}
+}

strategy/ctxmissing/ctxmissing_test.go

@@ -9,30 +9,14 @@
 package ctxmissing
 
 import (
-	log "github.com/cihub/seelog"
-	"github.com/stretchr/testify/assert"
+	"bytes"
 	"strings"
 	"testing"
-)
-
-type LogWriter struct {
-	Logs []string
-}
-
-func (sw *LogWriter) Write(p []byte) (n int, err error) {
-	sw.Logs = append(sw.Logs, string(p))
-	return len(p), nil
-}
 
-func LogSetup() *LogWriter {
-	writer := &LogWriter{}
-	logger, err := log.LoggerFromWriterWithMinLevelAndFormat(writer, log.TraceLvl, "%Ns [%Level] %Msg")
-	if err != nil {
-		panic(err)
-	}
-	log.ReplaceLogger(logger)
-	return writer
-}
+	"github.com/aws/aws-xray-sdk-go/internal/logger"
+	"github.com/aws/aws-xray-sdk-go/xraylog"
+	"github.com/stretchr/testify/assert"
+)
 
 func TestDefaultRuntimeErrorStrategy(t *testing.T) {
 	defer func() {
@@ -45,8 +29,13 @@ func TestDefaultRuntimeErrorStrategy(t *testing.T) {
 }
 
 func TestDefaultLogErrorStrategy(t *testing.T) {
-	logger := LogSetup()
+	oldLogger := logger.Logger
+	defer func() { logger.Logger = oldLogger }()
+
+	var buf bytes.Buffer
+	logger.Logger = xraylog.NewDefaultLogger(&buf, xraylog.LogLevelDebug)
+
 	l := NewDefaultLogErrorStrategy()
 	l.ContextMissing("TestLogError")
-	assert.True(t, strings.Contains(logger.Logs[0], "Suppressing AWS X-Ray context missing panic: TestLogError"))
+	assert.True(t, strings.Contains(buf.String(), "Suppressing AWS X-Ray context missing panic: TestLogError"))
 }

strategy/ctxmissing/default_context_missing.go

@@ -8,9 +8,7 @@
 
 package ctxmissing
 
-import (
-	log "github.com/cihub/seelog"
-)
+import "github.com/aws/aws-xray-sdk-go/internal/logger"
 
 // RuntimeErrorStrategy provides the AWS_XRAY_CONTEXT_MISSING
 // environment variable value for enabling the runtime error
@@ -50,5 +48,5 @@ func (dr *DefaultRuntimeErrorStrategy) ContextMissing(v interface{}) {
 // ContextMissing logs an error message when the
 // segment context is missing.
 func (dl *DefaultLogErrorStrategy) ContextMissing(v interface{}) {
-	log.Errorf("Suppressing AWS X-Ray context missing panic: %v", v)
+	logger.Errorf("Suppressing AWS X-Ray context missing panic: %v", v)
 }