colored labels output for logcli

cmd/logcli/main.go

@@ -25,7 +25,6 @@ var (
 	statistics = app.Flag("stats", "Show query statistics").Default("false").Bool()
 	outputMode = app.Flag("output", "Specify output mode [default, raw, jsonl]. raw suppresses log labels and timestamp.").Default("default").Short('o').Enum("default", "raw", "jsonl")
 	timezone   = app.Flag("timezone", "Specify the timezone to use when formatting output timestamps [Local, UTC]").Default("Local").Short('z').Enum("Local", "UTC")
-
 	cpuProfile = app.Flag("cpuprofile", "Specify the location for writing a CPU profile.").Default("").String()
 	memProfile = app.Flag("memprofile", "Specify the location for writing a memory profile.").Default("").String()
 
@@ -119,8 +118,9 @@ func main() {
 		}
 
 		outputOptions := &output.LogOutputOptions{
-			Timezone: location,
-			NoLabels: rangeQuery.NoLabels,
+			Timezone:      location,
+			NoLabels:      rangeQuery.NoLabels,
+			ColoredOutput: rangeQuery.ColoredOutput,
 		}
 
 		out, err := output.NewLogOutput(*outputMode, outputOptions)
@@ -140,8 +140,9 @@ func main() {
 		}
 
 		outputOptions := &output.LogOutputOptions{
-			Timezone: location,
-			NoLabels: instantQuery.NoLabels,
+			Timezone:      location,
+			NoLabels:      instantQuery.NoLabels,
+			ColoredOutput: instantQuery.ColoredOutput,
 		}
 
 		out, err := output.NewLogOutput(*outputMode, outputOptions)
@@ -280,6 +281,7 @@ func newQuery(instant bool, cmd *kingpin.CmdClause) *query.Query {
 	cmd.Flag("include-label", "Include labels given the provided key during output.").StringsVar(&q.ShowLabelsKey)
 	cmd.Flag("labels-length", "Set a fixed padding to labels").Default("0").IntVar(&q.FixedLabelsLen)
 	cmd.Flag("store-config", "Execute the current query using a configured storage from a given Loki configuration file.").Default("").StringVar(&q.LocalConfig)
+	cmd.Flag("colored-output", "Show ouput with colored labels").Default("false").BoolVar(&q.ColoredOutput)
 
 	return q
 }

docs/sources/getting-started/logcli.md

@@ -198,6 +198,7 @@ Flags:
       --store-config=""    Execute the current query using a configured storage from a given Loki configuration file.
   -t, --tail               Tail the logs
       --delay-for=0        Delay in tailing by number of seconds to accumulate logs for re-ordering
+      --colored-output     Show ouput with colored labels
 
 Args:
   <query>  eg '{foo="bar",baz=~".*blip"} |~ ".*error.*"'

pkg/logcli/output/default.go

@@ -24,6 +24,11 @@ func (o *DefaultOutput) Format(ts time.Time, lbls loghttp.LabelSet, maxLabelsLen
 		return fmt.Sprintf("%s %s", color.BlueString(timestamp), line)
 	}
 
+	if o.options.ColoredOutput {
+		labelsColor := getColor(lbls.String()).SprintFunc()
+		return fmt.Sprintf("%s %s %s", color.BlueString(timestamp), labelsColor(padLabel(lbls, maxLabelsLen)), line)
+	}
+
 	return fmt.Sprintf("%s %s %s", color.BlueString(timestamp), color.RedString(padLabel(lbls, maxLabelsLen)), line)
 }
 

pkg/logcli/output/default_test.go

@@ -132,6 +132,49 @@ func TestDefaultOutput_FormatLabelsPadding(t *testing.T) {
 	}
 }
 
+func TestColorForLabels(t *testing.T) {
+	tests := map[string]struct {
+		labels      loghttp.LabelSet
+		otherLabels loghttp.LabelSet
+		expected    bool
+	}{
+
+		"different labels": {
+			loghttp.LabelSet(map[string]string{
+				"type": "test",
+				"app":  "loki",
+			}),
+			loghttp.LabelSet(map[string]string{
+				"type": "test",
+				"app":  "grafana-loki",
+			}),
+			false,
+		},
+		"same labels": {
+			loghttp.LabelSet(map[string]string{
+				"type": "test",
+				"app":  "loki",
+			}),
+			loghttp.LabelSet(map[string]string{
+				"type": "test",
+				"app":  "loki",
+			}),
+			true,
+		},
+	}
+
+	for testName, testData := range tests {
+		testData := testData
+
+		t.Run(testName, func(t *testing.T) {
+			t.Parallel()
+			labelsColor := getColor(testData.labels.String())
+			otherLablesColor := getColor(testData.otherLabels.String())
+			assert.Equal(t, testData.expected, labelsColor.Equals(otherLablesColor))
+		})
+	}
+}
+
 func findMaxLabelsLength(labelsList []loghttp.LabelSet) int {
 	maxLabelsLen := 0
 

pkg/logcli/output/output.go

@@ -2,20 +2,39 @@ package output
 
 import (
 	"fmt"
+	"hash/fnv"
 	"time"
 
+	"github.com/fatih/color"
+
 	"github.com/grafana/loki/pkg/loghttp"
 )
 
+// Blue color is excluded since we are already printing timestamp
+// in blue color
+var colorList = []*color.Color{
+	color.New(color.FgHiCyan),
+	color.New(color.FgCyan),
+	color.New(color.FgHiGreen),
+	color.New(color.FgGreen),
+	color.New(color.FgHiMagenta),
+	color.New(color.FgMagenta),
+	color.New(color.FgHiYellow),
+	color.New(color.FgYellow),
+	color.New(color.FgHiRed),
+	color.New(color.FgRed),
+}
+
 // LogOutput is the interface any output mode must implement
 type LogOutput interface {
 	Format(ts time.Time, lbls loghttp.LabelSet, maxLabelsLen int, line string) string
 }
 
 // LogOutputOptions defines options supported by LogOutput
 type LogOutputOptions struct {
-	Timezone *time.Location
-	NoLabels bool
+	Timezone      *time.Location
+	NoLabels      bool
+	ColoredOutput bool
 }
 
 // NewLogOutput creates a log output based on the input mode and options
@@ -41,3 +60,11 @@ func NewLogOutput(mode string, options *LogOutputOptions) (LogOutput, error) {
 		return nil, fmt.Errorf("unknown log output mode '%s'", mode)
 	}
 }
+
+func getColor(labels string) *color.Color {
+	hash := fnv.New32()
+	hash.Write([]byte(labels))
+	id := hash.Sum32() % uint32(len(colorList))
+	color := colorList[id]
+	return color
+}

pkg/logcli/output/output_test.go

@@ -8,7 +8,7 @@ import (
 )
 
 func TestNewLogOutput(t *testing.T) {
-	options := &LogOutputOptions{time.UTC, false}
+	options := &LogOutputOptions{time.UTC, false, false}
 
 	out, err := NewLogOutput("default", options)
 	assert.NoError(t, err)

pkg/logcli/query/query.go

@@ -50,8 +50,8 @@ type Query struct {
 	IgnoreLabelsKey []string
 	ShowLabelsKey   []string
 	FixedLabelsLen  int
-
-	LocalConfig string
+	ColoredOutput   bool
+	LocalConfig     string
 }
 
 // DoQuery executes the query and prints out the results