Replace the old log setup, with structured logging etc.

Fixes #11124

common/loggers/handlerterminal.go

@@ -0,0 +1,90 @@
+// 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
+
+import (
+	"fmt"
+	"io"
+	"strings"
+	"sync"
+
+	"github.com/bep/logg"
+)
+
+// newNoColoursHandler creates a new NoColoursHandler
+func newNoColoursHandler(outWriter, errWriter io.Writer, noLevelPrefix bool, predicate func(*logg.Entry) bool) *noColoursHandler {
+	if predicate == nil {
+		predicate = func(e *logg.Entry) bool { return true }
+	}
+	return &noColoursHandler{
+		noLevelPrefix: noLevelPrefix,
+		outWriter:     outWriter,
+		errWriter:     errWriter,
+		predicate:     predicate,
+	}
+}
+
+type noColoursHandler struct {
+	mu            sync.Mutex
+	outWriter     io.Writer // Defaults to os.Stdout.
+	errWriter     io.Writer // Defaults to os.Stderr.
+	predicate     func(*logg.Entry) bool
+	noLevelPrefix bool
+}
+
+func (h *noColoursHandler) HandleLog(e *logg.Entry) error {
+	if !h.predicate(e) {
+		return nil
+	}
+	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 + ": "
+	}
+
+	if h.noLevelPrefix {
+		fmt.Fprintf(w, "%s%s", prefix, e.Message)
+	} else {
+		fmt.Fprintf(w, "%s %s%s", levelString[e.Level], prefix, e.Message)
+	}
+
+	for _, field := range e.Fields {
+		if strings.HasPrefix(field.Name, reservedFieldNamePrefix) {
+			continue
+		}
+		fmt.Fprintf(w, " %s %q", field.Name, field.Value)
+
+	}
+	fmt.Fprintln(w)
+
+	return nil
+}