moby/pkg/jsonlog/jsonlog.go
Brian Goff bd9d14a07b Add support for reading logs extra attrs
The jsonlog logger currently allows specifying envs and labels that
should be propagated to the log message, however there has been no way
to read that back.

This adds a new API option to enable inserting these attrs back to the
log reader.

With timestamps, this looks like so:
```
92016-04-08T15:28:09.835913720Z foo=bar,hello=world hello
```

The extra attrs are comma separated before the log message but after
timestamps.

Without timestaps it looks like so:
```
foo=bar,hello=world hello
```

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2016-05-06 20:42:20 -04:00

42 lines
1.2 KiB
Go

package jsonlog
import (
"encoding/json"
"fmt"
"time"
)
// JSONLog represents a log message, typically a single entry from a given log stream.
// JSONLogs can be easily serialized to and from JSON and support custom formatting.
type JSONLog struct {
// Log is the log message
Log string `json:"log,omitempty"`
// Stream is the log source
Stream string `json:"stream,omitempty"`
// Created is the created timestamp of log
Created time.Time `json:"time"`
// Attrs is the list of extra attributes provided by the user
Attrs map[string]string `json:"attrs,omitempty"`
}
// Format returns the log formatted according to format
// If format is nil, returns the log message
// If format is json, returns the log marshaled in json format
// By default, returns the log with the log time formatted according to format.
func (jl *JSONLog) Format(format string) (string, error) {
if format == "" {
return jl.Log, nil
}
if format == "json" {
m, err := json.Marshal(jl)
return string(m), err
}
return fmt.Sprintf("%s %s", jl.Created.Format(format), jl.Log), nil
}
// Reset resets the log to nil.
func (jl *JSONLog) Reset() {
jl.Log = ""
jl.Stream = ""
jl.Created = time.Time{}
}