Writer: Loggo emoji writer

example/main.go

@@ -5,12 +5,16 @@ import (
 	"os"
 
 	"github.com/juju/loggo"
+	"github.com/juju/loggo/loggoemoji"
 )
 
 var logger = loggo.GetLogger("main")
 var rootLogger = loggo.GetLogger("")
 
 func main() {
+	loggo.ResetWriters()
+	loggo.RegisterWriter("emoji", loggoemoji.NewWriter(os.Stdout))
+
 	args := os.Args
 	if len(args) > 1 {
 		loggo.ConfigureLoggers(args[1])

loggoemoji/package_test.go

@@ -0,0 +1,14 @@
+// Copyright 2021 Canonical Ltd.
+// Licensed under the LGPLv3, see LICENCE file for details.
+
+package loggoemoji
+
+import (
+	"testing"
+
+	gc "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) {
+	gc.TestingT(t)
+}

loggoemoji/writer.go

@@ -0,0 +1,67 @@
+// Copyright 2021 Canonical Ltd.
+// Licensed under the LGPLv3, see LICENCE file for details.
+
+package loggoemoji
+
+import (
+	"fmt"
+	"io"
+	"path/filepath"
+
+	"github.com/juju/ansiterm"
+	"github.com/juju/loggo"
+)
+
+type levelContext struct {
+	Emoji string
+	Style *ansiterm.Context
+}
+
+var (
+	// SeverityEmoji defines the colors for the levels output by the ColorWriter.
+	SeverityEmoji = map[loggo.Level]levelContext{
+		loggo.TRACE:   {Emoji: "✏️", Style: ansiterm.Foreground(ansiterm.Default)},
+		loggo.DEBUG:   {Emoji: "🐞", Style: ansiterm.Foreground(ansiterm.Green)},
+		loggo.INFO:    {Emoji: "🧐", Style: ansiterm.Foreground(ansiterm.BrightBlue)},
+		loggo.WARNING: {Emoji: "⚠️ ", Style: ansiterm.Foreground(ansiterm.Yellow)},
+		loggo.ERROR:   {Emoji: "😱", Style: ansiterm.Foreground(ansiterm.BrightRed)},
+		loggo.CRITICAL: {Emoji: "💥", Style: &ansiterm.Context{
+			Foreground: ansiterm.White,
+			Background: ansiterm.Red,
+		}},
+	}
+	// LocationColor defines the colors for the location output by the ColorWriter.
+	LocationColor = ansiterm.Foreground(ansiterm.BrightBlue)
+)
+
+type emojiWriter struct {
+	writer *ansiterm.Writer
+}
+
+// NewWriter will write out colored severity levels if the writer is
+// outputting to a terminal.
+func NewWriter(writer io.Writer) loggo.Writer {
+	return &emojiWriter{ansiterm.NewWriter(writer)}
+}
+
+// NewColorWriter will write out colored severity levels whether or not the
+// writer is outputting to a terminal.
+func NewColorWriter(writer io.Writer) loggo.Writer {
+	w := ansiterm.NewWriter(writer)
+	w.SetColorCapable(true)
+	return &emojiWriter{w}
+}
+
+// Write implements Writer.
+func (w *emojiWriter) Write(entry loggo.Entry) {
+	ts := entry.Timestamp.Format(loggo.TimeFormat)
+	// Just get the basename from the filename
+	filename := filepath.Base(entry.Filename)
+
+	fmt.Fprintf(w.writer, "%s ", ts)
+	SeverityEmoji[entry.Level].Style.Fprintf(w.writer, entry.Level.Short())
+	fmt.Fprintf(w.writer, " %s", SeverityEmoji[entry.Level].Emoji)
+	fmt.Fprintf(w.writer, " %s ", entry.Module)
+	LocationColor.Fprintf(w.writer, "%s:%d ", filename, entry.Line)
+	fmt.Fprintln(w.writer, entry.Message)
+}

loggoemoji/writer_test.go

@@ -0,0 +1,53 @@
+// Copyright 2021 Canonical Ltd.
+// Licensed under the LGPLv3, see LICENCE file for details.
+
+package loggoemoji
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/juju/loggo"
+	gc "gopkg.in/check.v1"
+)
+
+type WriterSuite struct{}
+
+var _ = gc.Suite(&WriterSuite{})
+
+func (s *WriterSuite) TestWriteEmoji(c *gc.C) {
+	tests := []struct {
+		Level    loggo.Level
+		Expected string
+	}{{
+		Level:    loggo.TRACE,
+		Expected: "✏️",
+	}, {
+		Level:    loggo.DEBUG,
+		Expected: "🐞",
+	}, {
+		Level:    loggo.INFO,
+		Expected: "🧐",
+	}, {
+		Level:    loggo.WARNING,
+		Expected: "⚠️ ",
+	}, {
+		Level:    loggo.ERROR,
+		Expected: "😱",
+	}, {
+		Level:    loggo.CRITICAL,
+		Expected: "💥",
+	}}
+	for i, test := range tests {
+		c.Logf("test %d level %s", i, test.Level.Short())
+
+		buf := new(bytes.Buffer)
+		writer := NewWriter(buf)
+		writer.Write(loggo.Entry{
+			Level:   test.Level,
+			Message: "Hello",
+		})
+
+		c.Assert(buf.String(), gc.Equals, fmt.Sprintf("00:00:00 %s %s  .:0 Hello\n", test.Level.Short(), test.Expected))
+	}
+}