Log to stdout instead of stderr

Signed-off-by: Andy Goldstein <andy.goldstein@gmail.com>

pkg/cmd/server/server.go

@@ -21,6 +21,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"net/http"
 	"os"
 	"reflect"
@@ -85,9 +86,16 @@ func NewCommand() *cobra.Command {
 		Short: "Run the ark server",
 		Long:  "Run the ark server",
 		Run: func(c *cobra.Command, args []string) {
+			// go-plugin uses log.Println to log when it's waiting for all plugin processes to complete so we need to
+			// set its output to stdout.
+			log.SetOutput(os.Stdout)
+
 			logLevel := logLevelFlag.Parse()
+			// Make sure we log to stdout so cloud log dashboards don't show this as an error.
+			logrus.SetOutput(os.Stdout)
 			logrus.Infof("setting log-level to %s", strings.ToUpper(logLevel.String()))
 
+			// Ark's DefaultLogger logs to stdout, so all is good there.
 			logger := logging.DefaultLogger(logLevel)
 			logger.Infof("Starting Ark server %s", buildinfo.FormattedGitSHA())
 

pkg/plugin/logger.go

@@ -26,6 +26,13 @@ import (
 // Ark plugin.
 func NewLogger() logrus.FieldLogger {
 	logger := logrus.New()
+	/*
+		!!!DO NOT SET THE OUTPUT TO STDOUT!!!
+
+		go-plugin uses stdout for a communications protocol between client and server.
+
+		stderr is used for log messages from server to client. The ark server makes sure they are logged to stdout.
+	*/
 
 	// we use the JSON formatter because go-plugin will parse incoming
 	// JSON on stderr and use it to create structured log entries.

pkg/util/logging/default_logger.go

@@ -1,6 +1,24 @@
+/*
+Copyright 2018 the Heptio Ark contributors.
+
+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.
+*/
+
 package logging
 
 import (
+	"os"
+
 	"github.com/sirupsen/logrus"
 )
 
@@ -17,6 +35,10 @@ func DefaultHooks() []logrus.Hook {
 // and hooks.
 func DefaultLogger(level logrus.Level) *logrus.Logger {
 	logger := logrus.New()
+
+	// Make sure the output is set to stdout so log messages don't show up as errors in cloud log dashboards.
+	logger.Out = os.Stdout
+
 	logger.Level = level
 
 	for _, hook := range DefaultHooks() {

pkg/util/logging/default_logger_test.go

@@ -0,0 +1,35 @@
+/*
+Copyright 2018 the Heptio Ark contributors.
+
+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.
+*/
+
+package logging
+
+import (
+	"os"
+	"testing"
+
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDefaultLogger(t *testing.T) {
+	logger := DefaultLogger(logrus.InfoLevel)
+	assert.Equal(t, logrus.InfoLevel, logger.Level)
+	assert.Equal(t, os.Stdout, logger.Out)
+
+	for _, level := range logrus.AllLevels {
+		assert.Equal(t, DefaultHooks(), logger.Hooks[level])
+	}
+}