initial commit

handler.go

@@ -0,0 +1,182 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"log"
+	"log/slog"
+	"regexp"
+	"slices"
+	"strings"
+	"sync"
+
+	"gopkg.in/yaml.v3"
+
+	"github.com/fatih/color"
+)
+
+const defaultTimeFormat = "2006-01-02T03:04.05 MST"
+
+type YamlDumpHandler struct {
+	l           *log.Logger
+	writer      io.Writer
+	mu          *sync.Mutex
+	level       slog.Leveler
+	groups      []string
+	attrs       string
+	timeFormat  string
+	replaceAttr func(groups []string, a slog.Attr) slog.Attr
+	addSource   bool
+	indenter    *regexp.Regexp
+}
+
+type YamlDumpHandlerOptions struct {
+	Level       slog.Leveler
+	ReplaceAttr func(groups []string, a slog.Attr) slog.Attr
+	TimeFormat  string
+	AddSource   bool
+}
+
+func (h *YamlDumpHandler) Handle(ctx context.Context, r slog.Record) error {
+	level := r.Level.String() + ":"
+
+	switch r.Level {
+	case slog.LevelDebug:
+		level = color.MagentaString(level)
+	case slog.LevelInfo:
+		level = color.BlueString(level)
+	case slog.LevelWarn:
+		level = color.YellowString(level)
+	case slog.LevelError:
+		level = color.RedString(level)
+	}
+
+	fields := make(map[string]interface{}, r.NumAttrs())
+	r.Attrs(func(a slog.Attr) bool {
+		fields[a.Key] = a.Value.Any()
+		return true
+	})
+
+	tree := h.attrs
+
+	if len(fields) > 0 {
+		bytetree, err := yaml.Marshal(&fields)
+		if err != nil {
+			return err
+		}
+
+		tree = h.Postprocess(bytetree)
+	}
+
+	timeStr := ""
+	timeAttr := slog.Time(slog.TimeKey, r.Time)
+
+	if h.replaceAttr != nil {
+		timeAttr = h.replaceAttr(nil, timeAttr)
+	}
+
+	if !r.Time.IsZero() && !timeAttr.Equal(slog.Attr{}) {
+		timeStr = r.Time.Format(h.timeFormat)
+	}
+
+	msg := color.CyanString(r.Message)
+
+	buf := bytes.Buffer{}
+
+	if len(timeStr) > 0 {
+		buf.WriteString(timeStr)
+		buf.WriteString(" ")
+	}
+	buf.WriteString(level)
+	buf.WriteString(" ")
+	buf.WriteString(msg)
+	buf.WriteString(" ")
+	buf.WriteString(color.WhiteString(tree))
+	buf.WriteString("\n")
+
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	_, err := h.writer.Write(buf.Bytes())
+
+	//	h.l.Println(timeStr, level, msg, color.WhiteString(tree))
+
+	return err
+}
+
+func (h *YamlDumpHandler) Postprocess(yamlstr []byte) string {
+	return "\n    " + strings.TrimSpace(h.indenter.ReplaceAllString(string(yamlstr), "    "))
+}
+
+func NewYamlDumpHandler(out io.Writer, opts *YamlDumpHandlerOptions) *YamlDumpHandler {
+	if opts == nil {
+		opts = &YamlDumpHandlerOptions{}
+	}
+
+	h := &YamlDumpHandler{
+		writer:      out,
+		mu:          &sync.Mutex{},
+		level:       opts.Level,
+		timeFormat:  opts.TimeFormat,
+		replaceAttr: opts.ReplaceAttr,
+		addSource:   opts.AddSource,
+		indenter:    regexp.MustCompile(`(?m)^`),
+	}
+
+	if h.timeFormat == "" {
+		h.timeFormat = defaultTimeFormat
+	}
+
+	return h
+}
+
+// Enabled indicates whether the receiver logs at the given level.
+func (h *YamlDumpHandler) Enabled(_ context.Context, l slog.Level) bool {
+	return l >= h.level.Level()
+}
+
+// attributes plus attrs.
+func (h *YamlDumpHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	if len(attrs) == 0 {
+		return h
+	}
+
+	fields := make(map[string]interface{}, len(attrs))
+	for _, a := range attrs {
+		fields[a.Key] = a.Value.Any()
+	}
+
+	bytetree, err := yaml.Marshal(&fields)
+	if err != nil {
+		panic(err)
+	}
+
+	h2 := h.clone()
+
+	h2.attrs += string(bytetree)
+	return h2
+}
+
+// WithGroup returns a new [log/slog.Handler] with name appended to the
+// receiver's groups.
+func (h *YamlDumpHandler) WithGroup(name string) slog.Handler {
+	if name == "" {
+		return h
+	}
+	h2 := h.clone()
+	h2.groups = append(h2.groups, name)
+	return h2
+}
+
+func (h *YamlDumpHandler) clone() *YamlDumpHandler {
+	return &YamlDumpHandler{
+		writer:      h.writer,
+		mu:          h.mu,
+		level:       h.level,
+		groups:      slices.Clip(h.groups),
+		attrs:       h.attrs,
+		timeFormat:  h.timeFormat,
+		replaceAttr: h.replaceAttr,
+		addSource:   h.addSource,
+	}
+}