canal,dump: Improve logging (#953)

Author: dveeden

README.md

@@ -24,6 +24,7 @@ This repo uses [Changelog](CHANGELOG.md).
 * [Client](#client)
 * [Fake server](#server)
 * [database/sql like driver](#driver)
+* [Logging](#logging)
 
 ## Replication
 
@@ -492,6 +493,29 @@ func main() {
 
 We pass all tests in https://github.com/bradfitz/go-sql-test using go-mysql driver. :-)
 
+## Logging
+
+Logging by default is send to stdout.
+
+To disable logging completely:
+```go
+import "github.com/siddontang/go-log/log"
+...
+ nullHandler, _ := log.NewNullHandler()
+ cfg.Logger = log.NewDefault(nullHandler)
+```
+
+To write logging to any [`io.Writer`](https://pkg.go.dev/io#Writer):
+```go
+import "github.com/siddontang/go-log/log"
+...
+ w := ...
+ streamHandler, _ := log.NewStreamHandler(w)
+ cfg.Logger = log.NewDefault(streamHandler)
+```
+
+Or you can implement your own [`log.Handler`](https://pkg.go.dev/github.com/siddontang/go-log/log#Handler).
+
 ## Donate
 
 If you like the project and want to buy me a cola, you can through: 

canal/canal.go

@@ -153,6 +153,9 @@ func (c *Canal) prepareDumper() error {
 return nil
 }
 
+// use the same logger for the dumper
+c.dumper.Logger = c.cfg.Logger
+
 dbs := c.cfg.Dump.Databases
 tables := c.cfg.Dump.Tables
 tableDB := c.cfg.Dump.TableDB

dump/dumper.go

@@ -13,6 +13,7 @@ import (
 . "github.com/go-mysql-org/go-mysql/mysql"
 "github.com/pingcap/errors"
 "github.com/siddontang/go-log/log"
+"github.com/siddontang/go-log/loggers"
 )
 
 // Unlick mysqldump, Dumper is designed for parsing and syning data easily.
@@ -49,6 +50,8 @@ type Dumper struct {
 
 mysqldumpVersion string
 sourceDataSupported bool
+
+Logger loggers.Advanced
 }
 
 func NewDumper(executionPath string, addr string, user string, password string) (*Dumper, error) {
@@ -93,6 +96,9 @@ func NewDumper(executionPath string, addr string, user string, password string)
 
 d.ErrOut = os.Stderr
 
+streamHandler, _ := log.NewStreamHandler(os.Stdout)
+d.Logger = log.NewDefault(streamHandler)
+
 return d, nil
 }
 
@@ -306,7 +312,7 @@ func (d *Dumper) Dump(w io.Writer) error {
 }
 
 args[passwordArgIndex] = "--password=******"
-log.Infof("exec mysqldump with %v", args)
+d.Logger.Infof("exec mysqldump with %v", args)
 args[passwordArgIndex] = passwordArg
 cmd := exec.Command(d.ExecutionPath, args...)