first commit

pkg/logger/logger.go

@@ -0,0 +1,173 @@
+/*
+© Copyright IBM Corporation 2018, 2021
+
+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 logger provides utility functions for logging purposes
+package logger
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"os/user"
+	"strconv"
+	"sync"
+	"time"
+)
+
+// timestampFormat matches the format used by MQ messages (includes milliseconds)
+const timestampFormat string = "2006-01-02T15:04:05.000Z07:00"
+const debugLevel string = "DEBUG"
+const infoLevel string = "INFO"
+const errorLevel string = "ERROR"
+
+// A Logger is used to log messages to stdout
+type Logger struct {
+	mutex       sync.Mutex
+	writer      io.Writer
+	debug       bool
+	json        bool
+	processName string
+	pid         string
+	serverName  string
+	host        string
+	userName    string
+}
+
+// NewLogger creates a new logger
+func NewLogger(writer io.Writer, debug bool, json bool, serverName string) (*Logger, error) {
+	hostname, err := os.Hostname()
+	if err != nil {
+		return nil, err
+	}
+	// This can fail because the container's running as a random UID which
+	// is not known by the OS.  We don't want this to break the logging
+	// entirely, so just use a blank user name.
+	user, err := user.Current()
+	userName := ""
+	if err == nil {
+		userName = user.Username
+	}
+	return &Logger{
+		mutex:       sync.Mutex{},
+		writer:      writer,
+		debug:       debug,
+		json:        json,
+		processName: os.Args[0],
+		pid:         strconv.Itoa(os.Getpid()),
+		serverName:  serverName,
+		host:        hostname,
+		userName:    userName,
+	}, nil
+}
+
+func (l *Logger) format(entry map[string]interface{}) (string, error) {
+	if l.json {
+		b, err := json.Marshal(entry)
+		if err != nil {
+			return "", err
+		}
+		return string(b), err
+	}
+	return fmt.Sprintf("%v %v\n", entry["ibm_datetime"], entry["message"]), nil
+}
+
+// log logs a message at the specified level.  The message is enriched with
+// additional fields.
+func (l *Logger) log(level string, msg string) {
+	t := time.Now()
+	entry := map[string]interface{}{
+		"message":         fmt.Sprint(msg),
+		"ibm_datetime":    t.Format(timestampFormat),
+		"loglevel":        level,
+		"host":            l.host,
+		"ibm_serverName":  l.serverName,
+		"ibm_processName": l.processName,
+		"ibm_processId":   l.pid,
+		"ibm_userName":    l.userName,
+		"type":            "mq_containerlog",
+	}
+	s, err := l.format(entry)
+	l.mutex.Lock()
+	if err != nil {
+		// TODO: Fix this
+		fmt.Println(err)
+	}
+	if l.json {
+		fmt.Fprintln(l.writer, s)
+	} else {
+		fmt.Fprint(l.writer, s)
+	}
+	l.mutex.Unlock()
+}
+
+// Debug logs a line as debug
+func (l *Logger) Debug(args ...interface{}) {
+	if l.debug {
+		if l.json {
+			l.log(debugLevel, fmt.Sprint(args...))
+		} else {
+			l.log(debugLevel, "DEBUG: "+fmt.Sprint(args...))
+		}
+	}
+}
+
+// Debugf logs a line as debug using format specifiers
+func (l *Logger) Debugf(format string, args ...interface{}) {
+	if l.debug {
+		if l.json {
+			l.log(debugLevel, fmt.Sprintf(format, args...))
+		} else {
+			l.log(debugLevel, fmt.Sprintf("DEBUG: "+format, args...))
+		}
+	}
+}
+
+// Print logs a message as info
+func (l *Logger) Print(args ...interface{}) {
+	l.log(infoLevel, fmt.Sprint(args...))
+}
+
+// Println logs a message
+func (l *Logger) Println(args ...interface{}) {
+	l.Print(args...)
+}
+
+// Printf logs a message as info using format specifiers
+func (l *Logger) Printf(format string, args ...interface{}) {
+	l.log(infoLevel, fmt.Sprintf(format, args...))
+}
+
+// PrintString logs a string as info
+func (l *Logger) PrintString(msg string) {
+	l.log(infoLevel, msg)
+}
+
+// Errorf logs a message as error
+func (l *Logger) Error(args ...interface{}) {
+	l.log(errorLevel, fmt.Sprint(args...))
+}
+
+// Errorf logs a message as error using format specifiers
+func (l *Logger) Errorf(format string, args ...interface{}) {
+	l.log(errorLevel, fmt.Sprintf(format, args...))
+}
+
+// Fatalf logs a message as fatal using format specifiers
+// TODO: Remove this
+func (l *Logger) Fatalf(format string, args ...interface{}) {
+	l.log("FATAL", fmt.Sprintf(format, args...))
+}

pkg/logger/logger_test.go

@@ -0,0 +1,55 @@
+/*
+© Copyright IBM Corporation 2018, 2019
+
+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 logger
+
+import (
+	"bytes"
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+func TestJSONLogger(t *testing.T) {
+	buf := new(bytes.Buffer)
+	l, err := NewLogger(buf, true, true, t.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	s := "Hello world"
+	l.Print(s)
+	var e map[string]interface{}
+	err = json.Unmarshal([]byte(buf.String()), &e)
+	if err != nil {
+		t.Error(err)
+	}
+	if s != e["message"] {
+		t.Errorf("Expected JSON to contain message=%v; got %v", s, buf.String())
+	}
+}
+
+func TestSimpleLogger(t *testing.T) {
+	buf := new(bytes.Buffer)
+	l, err := NewLogger(buf, true, false, t.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	s := "Hello world"
+	l.Print(s)
+	if !strings.Contains(buf.String(), s) {
+		t.Errorf("Expected log output to contain %v; got %v", s, buf.String())
+	}
+}