github.com/michael-k/docker@v1.7.0-rc2/pkg/jsonlog/jsonlog.go (about)

     1  package jsonlog
     2  
     3  import (
     4  	"encoding/json"
     5  	"fmt"
     6  	"io"
     7  	"time"
     8  )
     9  
    10  type JSONLog struct {
    11  	Log     string    `json:"log,omitempty"`
    12  	Stream  string    `json:"stream,omitempty"`
    13  	Created time.Time `json:"time"`
    14  }
    15  
    16  func (jl *JSONLog) Format(format string) (string, error) {
    17  	if format == "" {
    18  		return jl.Log, nil
    19  	}
    20  	if format == "json" {
    21  		m, err := json.Marshal(jl)
    22  		return string(m), err
    23  	}
    24  	return fmt.Sprintf("%s %s", jl.Created.Format(format), jl.Log), nil
    25  }
    26  
    27  func (jl *JSONLog) Reset() {
    28  	jl.Log = ""
    29  	jl.Stream = ""
    30  	jl.Created = time.Time{}
    31  }
    32  
    33  func WriteLog(src io.Reader, dst io.Writer, format string, since time.Time) error {
    34  	dec := json.NewDecoder(src)
    35  	l := &JSONLog{}
    36  	for {
    37  		l.Reset()
    38  		if err := dec.Decode(l); err != nil {
    39  			if err == io.EOF {
    40  				return nil
    41  			}
    42  			return err
    43  		}
    44  		if !since.IsZero() && l.Created.Before(since) {
    45  			continue
    46  		}
    47  
    48  		line, err := l.Format(format)
    49  		if err != nil {
    50  			return err
    51  		}
    52  		if _, err := io.WriteString(dst, line); err != nil {
    53  			return err
    54  		}
    55  	}
    56  }