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本文次要钻研一下golang的zap的marshaler
ObjectMarshaler
zap@v1.16.0/zapcore/marshaler.go
type ObjectMarshaler interface { MarshalLogObject(ObjectEncoder) error}// ObjectMarshalerFunc is a type adapter that turns a function into an// ObjectMarshaler.type ObjectMarshalerFunc func(ObjectEncoder) error// MarshalLogObject calls the underlying function.func (f ObjectMarshalerFunc) MarshalLogObject(enc ObjectEncoder) error { return f(enc)}ObjectMarshaler接口定义了MarshalLogObject办法；ObjectMarshalerFunc类型定义了MarshalLogObject办法，使得ObjectMarshalerFunc实现ObjectMarshaler接口
ArrayMarshaler
zap@v1.16.0/zapcore/marshaler.go
type ArrayMarshaler interface { MarshalLogArray(ArrayEncoder) error}// ArrayMarshalerFunc is a type adapter that turns a function into an// ArrayMarshaler.type ArrayMarshalerFunc func(ArrayEncoder) error// MarshalLogArray calls the underlying function.func (f ArrayMarshalerFunc) MarshalLogArray(enc ArrayEncoder) error { return f(enc)}ArrayMarshaler接口定义了MarshalLogArray办法；ArrayMarshalerFunc类型定义了MarshalLogArray办法，使得ArrayMarshalerFunc实现了MarshalLogArray接口
ObjectEncoder
zap@v1.16.0/zapcore/encoder.go
type ObjectEncoder interface { // Logging-specific marshalers. AddArray(key string, marshaler ArrayMarshaler) error AddObject(key string, marshaler ObjectMarshaler) error // Built-in types. AddBinary(key string, value []byte) // for arbitrary bytes AddByteString(key string, value []byte) // for UTF-8 encoded bytes AddBool(key string, value bool) AddComplex128(key string, value complex128) AddComplex64(key string, value complex64) AddDuration(key string, value time.Duration) AddFloat64(key string, value float64) AddFloat32(key string, value float32) AddInt(key string, value int) AddInt64(key string, value int64) AddInt32(key string, value int32) AddInt16(key string, value int16) AddInt8(key string, value int8) AddString(key, value string) AddTime(key string, value time.Time) AddUint(key string, value uint) AddUint64(key string, value uint64) AddUint32(key string, value uint32) AddUint16(key string, value uint16) AddUint8(key string, value uint8) AddUintptr(key string, value uintptr) // AddReflected uses reflection to serialize arbitrary objects, so it can be // slow and allocation-heavy. AddReflected(key string, value interface{}) error // OpenNamespace opens an isolated namespace where all subsequent fields will // be added. Applications can use namespaces to prevent key collisions when // injecting loggers into sub-components or third-party libraries. OpenNamespace(key string)}ObjectEncoder的AddArray办法须要ArrayMarshaler参数，AddObject办法须要ObjectMarshaler参数
zap.Object
zap@v1.16.0/field.go
// Object constructs a field with the given key and ObjectMarshaler. It// provides a flexible, but still type-safe and efficient, way to add map- or// struct-like user-defined types to the logging context. The struct's// MarshalLogObject method is called lazily.func Object(key string, val zapcore.ObjectMarshaler) Field { return Field{Key: key, Type: zapcore.ObjectMarshalerType, Interface: val}}zap.Object办法要求value实现zapcore.ObjectMarshaler接口
zap.Array
zap@v1.16.0/array.go
// Array constructs a field with the given key and ArrayMarshaler. It provides// a flexible, but still type-safe and efficient, way to add array-like types// to the logging context. The struct's MarshalLogArray method is called lazily.func Array(key string, val zapcore.ArrayMarshaler) Field { return Field{Key: key, Type: zapcore.ArrayMarshalerType, Interface: val}}zap.Array办法要求value实现了zapcore.ArrayMarshaler接口
实例
type User struct { Name string Email string CreatedAt time.Time}func (u *User) MarshalLogObject(enc zapcore.ObjectEncoder) error { enc.AddString("name", u.Name) enc.AddString("email", u.Email) enc.AddInt64("created_at", u.CreatedAt.UnixNano()) return nil}type Users []*Userfunc (uu Users) MarshalLogArray(arr zapcore.ArrayEncoder) error { var err error for i := range uu { err = multierr.Append(err, arr.AppendObject(uu[i])) } return err}func marshalerDemo() { logger, err := zap.NewProduction() defer logger.Sync() if err != nil { panic(err) } var user = &User{ Name: "hello1", Email: "hello1@test.com", CreatedAt: time.Date(2020, 12, 19, 8, 0, 0, 0, time.UTC), } var users Users users = append(users, &User{ Name: "hello2", Email: "hello2@test.com", CreatedAt: time.Date(2020, 12, 19, 9, 0, 0, 0, time.UTC), }, &User{ Name: "hello3", Email: "hello3@test.com", CreatedAt: time.Date(2020, 12, 20, 10, 0, 0, 0, time.UTC), }) logger.Info("marshaler", zap.Object("user", user)) logger.Info("marshaler", zap.Array("users", users))}User类型实现了MarshalLogObject办法；Users类型实现了MarshalLogArray办法；之后在logger增加Field的时候，就能够应用zap.Object或者zap.Array办法
输入
{"level":"info","ts":1608348349.487255,"caller":"zap/zap_demo.go:66","msg":"marshaler","user":{"name":"hello1","email":"hello1@test.com","created_at":1608364800000000000}}{"level":"info","ts":1608348349.4873412,"caller":"zap/zap_demo.go:67","msg":"marshaler","users":[{"name":"hello2","email":"hello2@test.com","created_at":1608368400000000000},{"name":"hello3","email":"hello3@test.com","created_at":1608458400000000000}]}小结
zap的marshaler定义了ObjectMarshaler(MarshalLogObject)及ArrayMarshaler(MarshalLogArray)接口；在logger若想应用zap.Object或者zap.Array办法就要求对应的类型实现对应的接口。
doc
- zap