gol4ng/logger

package formatter

import (
    "github.com/gol4ng/logger"
    "github.com/valyala/bytebufferpool"
    "strconv"
)

// JSON formatter will transform a logger entry into JSON
// it takes an encode function that allows you to encode the data
//
// the encode function is useful if you do not use the default provided logger implementation
type JSON struct {
    encode func(logger.Entry) ([]byte, error)
}

// Format will return Entry as json
func (j *JSON) Format(entry logger.Entry) string {
    b, _ := j.encode(entry)
    return string(b)
}

// NewJSONEncoder will create a new JSON with default json encoder function
func NewJSONEncoder() *JSON {
    return NewJSON(JSONEncoder)
}

// NewJSON will create a new JSON with given json encoder
// it allow you tu use your own json encoder
func NewJSON(encode func(logger.Entry) ([]byte, error)) *JSON {
    return &JSON{encode: encode}
}

// ContextToJSON will marshall the logger context into json
func ContextToJSON(context *logger.Context, byteBuffer *bytebufferpool.ByteBuffer) {
    if context == nil || len(*context) == 0 {
        byteBuffer.WriteString("null")
    } else {
        byteBuffer.WriteString(`{`)
        first := true
        for name, field := range *context {
            if !first {
                byteBuffer.WriteString(`,`)
            }
            byteBuffer.WriteString(`"`)
            byteBuffer.WriteString(name)
            byteBuffer.WriteString(`":`)
            d, _ := field.MarshalJSON()
            byteBuffer.Write(d)
            first = false
        }
        byteBuffer.WriteString(`}`)
    }
}

// EntryToJSON will marshall the logger Entry into json
func EntryToJSON(entry logger.Entry, byteBuffer *bytebufferpool.ByteBuffer) {
    byteBuffer.WriteString(`{"Message":"`)
    byteBuffer.WriteString(entry.Message)
    byteBuffer.WriteString(`","Level":`)
    byteBuffer.WriteString(strconv.Itoa(int(entry.Level)))
    byteBuffer.WriteString(`,"Context":`)
    ContextToJSON(entry.Context, byteBuffer)
    byteBuffer.WriteString(`}`)
}

// JSONEncoder will return Entry to json string
func JSONEncoder(entry logger.Entry) ([]byte, error) {
    byteBuffer := bytebufferpool.Get()
    defer bytebufferpool.Put(byteBuffer)

    EntryToJSON(entry, byteBuffer)

    return byteBuffer.Bytes(), nil
}