Replace the old log setup, with structured logging etc.

Fixes #11124

common/loggers/handlerdefault.go

@@ -0,0 +1,106 @@
+// Copyright 2023 The Hugo Authors. All rights reserved.
+// Some functions in this file (see comments) is based on the Go source code,
+// copyright The Go Authors and  governed by a BSD-style license.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// package loggers contains some basic logging setup.
+package loggers
+
+import (
+	"fmt"
+	"io"
+	"strings"
+	"sync"
+
+	"github.com/bep/logg"
+
+	"github.com/fatih/color"
+)
+
+var bold = color.New(color.Bold)
+
+// levelColor mapping.
+var levelColor = [...]*color.Color{
+	logg.LevelDebug: color.New(color.FgWhite),
+	logg.LevelInfo:  color.New(color.FgBlue),
+	logg.LevelWarn:  color.New(color.FgYellow),
+	logg.LevelError: color.New(color.FgRed),
+}
+
+// levelString mapping.
+var levelString = [...]string{
+	logg.LevelDebug: "DEBUG",
+	logg.LevelInfo:  "INFO ",
+	logg.LevelWarn:  "WARN ",
+	logg.LevelError: "ERROR",
+}
+
+// newDefaultHandler handler.
+func newDefaultHandler(outWriter, errWriter io.Writer) logg.Handler {
+	return &defaultHandler{
+		outWriter: outWriter,
+		errWriter: errWriter,
+		Padding:   0,
+	}
+}
+
+// Default Handler implementation.
+// Based on https://github.com/apex/log/blob/master/handlers/cli/cli.go
+type defaultHandler struct {
+	mu        sync.Mutex
+	outWriter io.Writer // Defaults to os.Stdout.
+	errWriter io.Writer // Defaults to os.Stderr.
+
+	Padding int
+}
+
+// HandleLog implements logg.Handler.
+func (h *defaultHandler) HandleLog(e *logg.Entry) error {
+	color := levelColor[e.Level]
+	level := levelString[e.Level]
+
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	var w io.Writer
+	if e.Level > logg.LevelInfo {
+		w = h.errWriter
+	} else {
+		w = h.outWriter
+	}
+
+	var prefix string
+	for _, field := range e.Fields {
+		if field.Name == FieldNameCmd {
+			prefix = fmt.Sprint(field.Value)
+			break
+		}
+	}
+
+	if prefix != "" {
+		prefix = prefix + ": "
+	}
+
+	color.Fprintf(w, "%s %s%s", bold.Sprintf("%*s", h.Padding+1, level), color.Sprint(prefix), e.Message)
+
+	for _, field := range e.Fields {
+		if strings.HasPrefix(field.Name, reservedFieldNamePrefix) {
+			continue
+		}
+		fmt.Fprintf(w, " %s %v", color.Sprint(field.Name), field.Value)
+	}
+
+	fmt.Fprintln(w)
+
+	return nil
+}