Add logger to client

v1/client.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"log"
 	"net/http"
 	"strings"
 	"time"
@@ -22,6 +23,22 @@ func New(url string, token string) *MgClient {
 	}
 }
 
+// WithLogger sets the provided logger instance into the Client.
+func (c *MgClient) WithLogger(logger BasicLogger) *MgClient {
+	c.logger = logger
+	return c
+}
+
+// writeLog writes to the log.
+func (c *MgClient) writeLog(format string, v ...interface{}) {
+	if c.logger != nil {
+		c.logger.Printf(format, v...)
+		return
+	}
+
+	log.Printf(format, v...)
+}
+
 // Bots get all available bots
 //
 // Example:

v1/client_test.go

@@ -1,6 +1,7 @@
 package v1
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"log"
@@ -830,3 +831,31 @@ func RandStringBytesMaskImprSrc(n int) string {
 
 	return string(b)
 }
+
+func TestMgClient_DebugNoLogger(t *testing.T) {
+	c := client()
+	c.Debug = true
+
+	var buf bytes.Buffer
+	log.SetOutput(&buf)
+	defer func() {
+		log.SetOutput(os.Stderr)
+	}()
+
+	c.writeLog("Test log string")
+
+	assert.Contains(t, buf.String(), "Test log string")
+}
+
+func TestMgClient_DebugWithLogger(t *testing.T) {
+	var buf bytes.Buffer
+	logger := log.New(&buf, "Custom log prefix ", 0)
+
+	c := client()
+	c.Debug = true
+	c.WithLogger(logger)
+
+	c.writeLog("Test log string")
+
+	assert.Contains(t, buf.String(), "Custom log prefix Test log string")
+}

v1/log.go

@@ -0,0 +1,25 @@
+package v1
+
+// BasicLogger provides basic functionality for logging.
+type BasicLogger interface {
+	Printf(string, ...interface{})
+}
+
+// DebugLogger can be used to easily wrap any logger with Debugf method into the BasicLogger instance.
+type DebugLogger interface {
+	Debugf(string, ...interface{})
+}
+
+type debugLoggerAdapter struct {
+	logger DebugLogger
+}
+
+// DebugLoggerAdapter returns BasicLogger that calls underlying DebugLogger.Debugf.
+func DebugLoggerAdapter(logger DebugLogger) BasicLogger {
+	return &debugLoggerAdapter{logger: logger}
+}
+
+// Printf data in the log using DebugLogger.Debugf.
+func (l *debugLoggerAdapter) Printf(format string, v ...interface{}) {
+	l.logger.Debugf(format, v...)
+}

v1/log_test.go

@@ -0,0 +1,24 @@
+package v1
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type wrappedLogger struct {
+	lastMessage string
+}
+
+func (w *wrappedLogger) Debugf(msg string, v ...interface{}) {
+	w.lastMessage = fmt.Sprintf(msg, v...)
+}
+
+func TestDebugLoggerAdapter_Printf(t *testing.T) {
+	wrapped := &wrappedLogger{}
+	logger := DebugLoggerAdapter(wrapped)
+	logger.Printf("Test message #%d", 1)
+
+	assert.Equal(t, "Test message #1", wrapped.lastMessage)
+}

v1/request.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"log"
 	"net/http"
 )
 
@@ -72,7 +71,7 @@ func makeRequest(reqType, url string, buf io.Reader, c *MgClient) ([]byte, int,
 	req.Header.Set("X-Bot-Token", c.Token)
 
 	if c.Debug {
-		log.Printf("MG BOT API Request: %s %s %s %+v", reqType, url, c.Token, buf)
+		c.writeLog("MG BOT API Request: %s %s %s %+v", reqType, url, c.Token, buf)
 	}
 
 	resp, err := c.httpClient.Do(req)
@@ -91,7 +90,7 @@ func makeRequest(reqType, url string, buf io.Reader, c *MgClient) ([]byte, int,
 	}
 
 	if c.Debug {
-		log.Printf("MG BOT API Response: %s", res)
+		c.writeLog("MG BOT API Response: %s", res)
 	}
 
 	return res, resp.StatusCode, err

v1/types.go

@@ -83,6 +83,7 @@ type MgClient struct {
 	Token      string `json:"token"`
 	Debug      bool   `json:"debug"`
 	httpClient *http.Client
+	logger     BasicLogger `json:"-"`
 }
 
 // Request types