implement logfmt formatter

Gopkg.lock

@@ -19,6 +19,12 @@
   packages = ["."]
   revision = "c6d800382fff6dc1412f34269f71b7f83bd059ad"
 
+[[projects]]
+  name = "github.com/go-logfmt/logfmt"
+  packages = ["."]
+  revision = "390ab7935ee28ec6b286364bba9b4dd6410cb3d5"
+  version = "v0.3.0"
+
 [[projects]]
   branch = "v2"
   name = "github.com/go-yaml/yaml"
@@ -43,6 +49,12 @@
   packages = ["."]
   revision = "db4671f3a9b8df855e993f7c94ec5ef1ffb0a23b"
 
+[[projects]]
+  branch = "master"
+  name = "github.com/kr/logfmt"
+  packages = ["."]
+  revision = "b84e30acd515aadc4b783ad4ff83aff3299bdfe0"
+
 [[projects]]
   branch = "master"
   name = "github.com/kr/pretty"
@@ -160,6 +172,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "bee0c80e0ddaadd7725a31b203d080be9e360fb17514e972ff2023c0b40cb004"
+  inputs-digest = "7ce2ead5225e4bb72a34132538171a649b26de574596e909730658ddbc904cd5"
   solver-name = "gps-cdcl"
   solver-version = 1

Gopkg.toml

@@ -60,3 +60,7 @@
 [[constraint]]
   branch = "v2"
   name = "github.com/go-yaml/yaml"
+
+[[constraint]]
+  name = "github.com/go-logfmt/logfmt"
+  version = "*"

cmd/config_logging.go

@@ -138,6 +138,8 @@ func parseLogFormat(i interface{}) (f EntryFormatter, err error) {
 	switch is {
 	case "human":
 		return &HumanFormatter{}, nil
+	case "logfmt":
+		return &LogfmtFormatter{}, nil
 	case "json":
 		return &JSONFormatter{}, nil
 	default:

cmd/logging_formatters.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"github.com/go-logfmt/logfmt"
 	"github.com/pkg/errors"
 	"github.com/zrepl/zrepl/logger"
 	"strings"
@@ -125,3 +126,49 @@ func (f *JSONFormatter) Format(e *logger.Entry) ([]byte, error) {
 	return json.Marshal(data)
 
 }
+
+type LogfmtFormatter struct {
+	NoMetadata bool
+}
+
+var _ SetNoMetadataFormatter = &LogfmtFormatter{}
+
+func (f *LogfmtFormatter) SetNoMetadata(noMetadata bool) {
+	f.NoMetadata = noMetadata
+}
+
+func (f *LogfmtFormatter) Format(e *logger.Entry) ([]byte, error) {
+	var buf bytes.Buffer
+	enc := logfmt.NewEncoder(&buf)
+
+	if !f.NoMetadata {
+		enc.EncodeKeyval(FieldTime, e.Time)
+		enc.EncodeKeyval(FieldLevel, e.Level)
+	}
+
+	// at least try and put job and task in front
+	prefixed := make(map[string]bool, 2)
+	prefix := []string{logJobField, logTaskField}
+	for _, pf := range prefix {
+		v, ok := e.Fields[pf]
+		if !ok {
+			break
+		}
+		enc.EncodeKeyval(pf, v)
+		prefixed[pf] = true
+	}
+
+	enc.EncodeKeyval(FieldMessage, e.Message)
+
+	for k, v := range e.Fields {
+		if !prefixed[k] {
+			enc.EncodeKeyval(k, v)
+		}
+	}
+
+	if err := enc.EndRecord(); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}