feat: introduce the zap log library (#15)

diff --git a/go.mod b/go.mod
index 7dcac3d..023ec91 100644
--- a/go.mod
+++ b/go.mod
@@ -11,5 +11,6 @@
 	github.com/xeipuuv/gojsonschema v1.2.0
 	github.com/yudai/gojsondiff v1.0.0
 	github.com/yudai/golcs v0.0.0-20170316035057-ecda9a501e82 // indirect
+	go.uber.org/zap v1.15.0
 	gopkg.in/yaml.v2 v2.3.0
 )
diff --git a/go.sum b/go.sum
index 3d9309c..b8fc16d 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,6 @@
+github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/fsnotify/fsnotify v1.4.9 h1:hsms1Qyu0jgnwNXIxa+/V/PDsU6CfLf6CNO8H7IWoS4=
@@ -16,6 +18,7 @@
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
 github.com/hashicorp/go-immutable-radix v1.2.0 h1:l6UW37iCXwZkZoAbEYnptSHVE/cQ5bOTPYG5W3vf9+8=
 github.com/hashicorp/go-immutable-radix v1.2.0/go.mod h1:0y9vanUI8NX6FsYoO3zeMjhV/C5i9g4Q3DwcSNZ4P60=
 github.com/hashicorp/go-memdb v1.2.1 h1:wI9btDjYUOJJHTCnRlAG/TkRyD/ij7meJMrLK9X31Cc=
@@ -25,6 +28,7 @@
 github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+lJfyTc=
 github.com/hashicorp/golang-lru v0.5.4/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
+github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
@@ -37,11 +41,15 @@
 github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7JYyY=
 github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/sergi/go-diff v1.1.0 h1:we8PVUC3FE2uYfodKH/nBHMSetSfHDR6scGdBi+erh0=
 github.com/sergi/go-diff v1.1.0/go.mod h1:STckp+ISIX8hZLjrqAeVduY0gWCT9IjLuqbuNXdaHfM=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f h1:J9EGpcZtP0E/raorCMxlFGSTBrsSlaDGf3jU/qvAE2c=
 github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=
@@ -53,13 +61,28 @@
 github.com/yudai/gojsondiff v1.0.0/go.mod h1:AY32+k2cwILAkW1fbgxQ5mUmMiZFgLIV+FBNExI05xg=
 github.com/yudai/golcs v0.0.0-20170316035057-ecda9a501e82 h1:BHyfKlQyqbsFN5p3IfnEUduWvb9is428/nNb5L3U01M=
 github.com/yudai/golcs v0.0.0-20170316035057-ecda9a501e82/go.mod h1:lgjkn3NuSvDfVJdfcVVdX+jpBxNmX4rDAzaS45IcYoM=
+go.uber.org/atomic v1.6.0 h1:Ezj3JGmsOnG1MoRWQkPBsKLe9DwWD9QeXzTRzzldNVk=
+go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
+go.uber.org/multierr v1.5.0 h1:KCa4XfM8CWFCpxXRGok+Q0SS/0XBhMDbHHGABQLvD2A=
+go.uber.org/multierr v1.5.0/go.mod h1:FeouvMocqHpRaaGuG9EjoKcStLC43Zu/fmqdUMPcKYU=
+go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee/go.mod h1:vJERXedbb3MVM5f9Ejo0C68/HhF8uaILCdgjnY+goOA=
+go.uber.org/zap v1.15.0 h1:ZZCA22JRF2gQE5FoNmhmrf7jeJJ2uhqDUNRYKm8dvmM=
+go.uber.org/zap v1.15.0/go.mod h1:Mb2vm2krFEG5DV0W9qcHBYFtp/Wku1cvYaqPsS/WYfc=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
+golang.org/x/mod v0.0.0-20190513183733-4bf6d317e70e/go.mod h1:mXi4GBBbnImb6dmsKGUJ2LatrhH/nqhxcFungHvyanc=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200520004742-59133d7f0dd7 h1:AeiKBIuRw3UomYXSbLy0Mc2dDLfdtbT/IVn4keq83P0=
 golang.org/x/net v0.0.0-20200520004742-59133d7f0dd7/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190904154756-749cb33beabd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -70,6 +93,11 @@
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
+golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
+golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
@@ -80,7 +108,9 @@
 google.golang.org/protobuf v1.23.0 h1:4MY060fB1DLGMB/7MBTLnwQUY6+F09GEiz6SsrNqyzM=
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 h1:uRGJdciOHaEIrze2W8Q3AKkepLTh2hOroT7a+7czfdQ=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
@@ -88,3 +118,4 @@
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
diff --git a/pkg/log/logger.go b/pkg/log/logger.go
new file mode 100644
index 0000000..b8fd2b4
--- /dev/null
+++ b/pkg/log/logger.go
@@ -0,0 +1,73 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 log
+
+import (
+	"os"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+var logger *zap.Logger = zap.NewNop()
+
+var level zap.AtomicLevel = zap.NewAtomicLevel()
+
+func init() {
+	Init()
+}
+
+// Level returns the current log level so that we can do extra things according
+// to the current mode
+func Level() zap.AtomicLevel {
+	return level
+}
+
+func Init() {
+	// TODO use different log level in different environment
+	lv := zapcore.InfoLevel
+	level.SetLevel(lv)
+
+	var cores []zapcore.Core
+	consoleEncoder := zapcore.NewConsoleEncoder(zap.NewDevelopmentEncoderConfig())
+	// default to stderr
+	cores = append(cores, zapcore.NewCore(consoleEncoder, os.Stderr, level))
+	core := zapcore.NewTee(cores...)
+	// add line and stack info (under error log level)
+	logger = zap.New(core, zap.AddStacktrace(zap.ErrorLevel), zap.AddCaller())
+}
+
+// Errorw logs the error occurs with the stacktrace
+func Errorw(msg string, kv ...interface{}) {
+	logger.Sugar().Errorw(msg, kv...)
+}
+
+// Warnw logs what happened unexpectedly but don't need to be handled immediately
+func Warnw(msg string, kv ...interface{}) {
+	logger.Sugar().Warnw(msg, kv...)
+}
+
+// Infow logs what happened normally
+func Infow(msg string, kv ...interface{}) {
+	logger.Sugar().Infow(msg, kv...)
+}
+
+// Debugw logs the details for debug
+func Debugw(msg string, kv ...interface{}) {
+	logger.Sugar().Debugw(msg, kv...)
+}
diff --git a/pkg/mem/diff.go b/pkg/mem/diff.go
index 2a1e1d7..a1a815d 100644
--- a/pkg/mem/diff.go
+++ b/pkg/mem/diff.go
@@ -19,8 +19,10 @@
 
 import (
 	"encoding/json"
-	"fmt"
+
 	"github.com/yudai/gojsondiff"
+
+	"github.com/apache/apisix-control-plane/pkg/log"
 )
 
 var (
@@ -39,7 +41,7 @@
 	if d, err := differ.Compare(aJSON, bJSON); err != nil {
 		return false, err
 	} else {
-		fmt.Println(d.Deltas())
+		log.Debugw("diff result", "deltas", d.Deltas())
 		return d.Modified(), nil
 	}
 }
diff --git a/pkg/mem/gateway.go b/pkg/mem/gateway.go
index f41f3f0..59a9f50 100644
--- a/pkg/mem/gateway.go
+++ b/pkg/mem/gateway.go
@@ -27,7 +27,6 @@
 
 // insert Gateway to memDB
 func (db *GatewayDB) Insert() error {
-	fmt.Println(DB)
 	txn := DB.Txn(true)
 	defer txn.Abort()
 	for _, r := range db.Gateways {
diff --git a/pkg/yml/schema.go b/pkg/yml/schema.go
index 4cfb127..56f6d95 100644
--- a/pkg/yml/schema.go
+++ b/pkg/yml/schema.go
@@ -18,7 +18,10 @@
 
 import (
 	"fmt"
+
 	"github.com/xeipuuv/gojsonschema"
+
+	"github.com/apache/apisix-control-plane/pkg/log"
 )
 
 // YamlSchema define schema rule
@@ -179,13 +182,13 @@
 	schemaLoader := gojsonschema.NewStringLoader(YamlSchema())
 	schema, err := gojsonschema.NewSchema(schemaLoader)
 	if err != nil {
-		fmt.Println(err.Error())
+		log.Errorw("new schema failed", "err", err)
 		return false, err
 	}
 	requestLoader := gojsonschema.NewStringLoader(request)
 	result, err := schema.Validate(requestLoader)
 	if err != nil {
-		fmt.Println(err.Error())
+		log.Errorw("validate failed", "err", err)
 		return false, err
 	}
 	if result.Valid() {
diff --git a/pkg/yml/trans.go b/pkg/yml/trans.go
index b3a3390..c818bf2 100644
--- a/pkg/yml/trans.go
+++ b/pkg/yml/trans.go
@@ -19,15 +19,17 @@
 
 import (
 	"encoding/json"
-	"fmt"
+
 	"gopkg.in/yaml.v2"
+
+	"github.com/apache/apisix-control-plane/pkg/log"
 )
 
 func Trans(b []byte, y []byte) YmlModel {
 	// 1.trans with kind
 	var yMap map[string]interface{}
 	if err := json.Unmarshal(b, &yMap); err != nil {
-		fmt.Println("trans to map error")
+		log.Errorw("unmarshal json failed", "err", err, "raw", string(b))
 		return nil
 	} else {
 		kind := yMap["kind"]
@@ -35,7 +37,6 @@
 		case "Gateway":
 			// trans to Gateway
 			if g, err := ToGateway(y); err != nil {
-				fmt.Println("trans to Gateway error ", err)
 				return nil
 			} else {
 				return g
@@ -43,7 +44,6 @@
 		case "Destination":
 			// trans to Destination
 			if g, err := ToDestination(y); err != nil {
-				fmt.Println("trans to destination error ", err)
 				return nil
 			} else {
 				return g
@@ -51,7 +51,6 @@
 		case "Rule":
 			// trans to Rule
 			if r, err := ToRule(y); err != nil {
-				fmt.Println("trans to Rule error ", err)
 				return nil
 			} else {
 				return r
@@ -59,13 +58,12 @@
 		case "Plugin":
 			// trans to Plugin
 			if r, err := ToPlugin(y); err != nil {
-				fmt.Println("trans to Plugin error ", err)
 				return nil
 			} else {
 				return r
 			}
 		default:
-			fmt.Println("nil")
+			log.Warnw("unknown kind", "kind", kind)
 			return nil
 		}
 	}
@@ -74,7 +72,7 @@
 func ToGateway(y []byte) (*Gateway, error) {
 	var g *Gateway
 	if err := yaml.Unmarshal(y, &g); err != nil {
-		fmt.Println(err)
+		log.Errorw("unmarshal yaml failed", "err", err, "raw", string(y))
 		return nil, err
 	} else {
 		return g, nil
@@ -84,7 +82,7 @@
 func ToRule(y []byte) (*Rule, error) {
 	var r *Rule
 	if err := yaml.Unmarshal(y, &r); err != nil {
-		fmt.Println(err)
+		log.Errorw("unmarshal yaml failed", "err", err, "raw", string(y))
 		return nil, err
 	} else {
 		return r, nil
@@ -94,7 +92,7 @@
 func ToDestination(y []byte) (*Destination, error) {
 	var g *Destination
 	if err := yaml.Unmarshal(y, &g); err != nil {
-		fmt.Println(err)
+		log.Errorw("unmarshal yaml failed", "err", err, "raw", string(y))
 		return nil, err
 	} else {
 		return g, nil
@@ -104,7 +102,7 @@
 func ToPlugin(y []byte) (*Plugin, error) {
 	var g *Plugin
 	if err := yaml.Unmarshal(y, &g); err != nil {
-		fmt.Println(err)
+		log.Errorw("unmarshal yaml failed", "err", err, "raw", string(y))
 		return nil, err
 	} else {
 		return g, nil