Implement handlers to normalise how logging is handled

internal/log/handlers/batch/batch.go

@@ -0,0 +1,33 @@
+package batch
+
+import (
+	j "encoding/json"
+	"io"
+	"os"
+	"sync"
+
+	"github.com/apex/log"
+)
+
+// Default handler outputting to stderr.
+var Default = New(os.Stderr)
+
+// Handler implementation.
+type Handler struct {
+	*j.Encoder
+	mu sync.Mutex
+}
+
+// New handler.
+func New(w io.Writer) *Handler {
+	return &Handler{
+		Encoder: j.NewEncoder(w),
+	}
+}
+
+// HandleLog implements log.Handler.
+func (h *Handler) HandleLog(e *log.Entry) error {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return h.Encoder.Encode(e)
+}

internal/log/handlers/cli/cli.go

@@ -0,0 +1,84 @@
+package cli
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/apex/log"
+	"github.com/fatih/color"
+	colorable "github.com/mattn/go-colorable"
+)
+
+// Default handler outputting to stderr.
+var Default = New(os.Stderr)
+
+// start time.
+var start = time.Now()
+
+var bold = color.New(color.Bold)
+
+// Colors mapping.
+var Colors = [...]*color.Color{
+	log.DebugLevel: color.New(color.FgWhite),
+	log.InfoLevel:  color.New(color.FgBlue),
+	log.WarnLevel:  color.New(color.FgYellow),
+	log.ErrorLevel: color.New(color.FgRed),
+	log.FatalLevel: color.New(color.FgRed),
+}
+
+// Strings mapping.
+var Strings = [...]string{
+	log.DebugLevel: "•",
+	log.InfoLevel:  "•",
+	log.WarnLevel:  "•",
+	log.ErrorLevel: "⨯",
+	log.FatalLevel: "⨯",
+}
+
+// Handler implementation.
+type Handler struct {
+	mu      sync.Mutex
+	Writer  io.Writer
+	Padding int
+}
+
+// New handler.
+func New(w io.Writer) *Handler {
+	if f, ok := w.(*os.File); ok {
+		return &Handler{
+			Writer:  colorable.NewColorable(f),
+			Padding: 3,
+		}
+	}
+
+	return &Handler{
+		Writer:  w,
+		Padding: 3,
+	}
+}
+
+// HandleLog implements log.Handler.
+func (h *Handler) HandleLog(e *log.Entry) error {
+	color := Colors[e.Level]
+	level := Strings[e.Level]
+	names := e.Fields.Names()
+
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	color.Fprintf(h.Writer, "%s %-25s", bold.Sprintf("%*s", h.Padding+1, level), e.Message)
+
+	for _, name := range names {
+		if name == "source" {
+			continue
+		}
+		fmt.Fprintf(h.Writer, " %s=%s", color.Sprint(name), e.Fields.Get(name))
+	}
+
+	fmt.Fprintln(h.Writer)
+
+	return nil
+}