netdata/netdata

package logger

import (
    "context"
    "log/slog"
    "os"
    "runtime"
    "strings"

    "github.com/lmittmann/tint"
)

func newTextHandler() slog.Handler {
    return slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
        Level: Level.lvl,
        ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
            switch a.Key {
            case slog.TimeKey:
                if isJournal {
                    return slog.Attr{}
                }
            case slog.LevelKey:
                lvl := a.Value.Any().(slog.Level)
                s, ok := customLevels[lvl]
                if !ok {
                    s = lvl.String()
                }
                return slog.String(a.Key, strings.ToLower(s))
            }
            return a
        },
    })
}

func newTerminalHandler() slog.Handler {
    return tint.NewHandler(os.Stderr, &tint.Options{
        AddSource: true,
        Level:     Level.lvl,
        ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
            switch a.Key {
            case slog.TimeKey:
                return slog.Attr{}
            case slog.SourceKey:
                if !Level.Enabled(slog.LevelDebug) {
                    return slog.Attr{}
                }
            case slog.LevelKey:
                lvl := a.Value.Any().(slog.Level)
                if s, ok := customLevelsTerm[lvl]; ok {
                    return slog.String(a.Key, s)
                }
            }
            return a
        },
    })
}

func withCallDepth(depth int, sh slog.Handler) slog.Handler {
    if v, ok := sh.(*callDepthHandler); ok {
        sh = v.sh
    }
    return &callDepthHandler{depth: depth, sh: sh}
}

type callDepthHandler struct {
    depth int
    sh    slog.Handler
}

func (h *callDepthHandler) Enabled(ctx context.Context, level slog.Level) bool {
    return h.sh.Enabled(ctx, level)
}

func (h *callDepthHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
    return withCallDepth(h.depth, h.sh.WithAttrs(attrs))
}

func (h *callDepthHandler) WithGroup(name string) slog.Handler {
    return withCallDepth(h.depth, h.sh.WithGroup(name))
}

func (h *callDepthHandler) Handle(ctx context.Context, r slog.Record) error {
    // https://pkg.go.dev/log/slog#example-package-Wrapping
    var pcs [1]uintptr
    // skip Callers and this function
    runtime.Callers(h.depth+2, pcs[:])
    r.PC = pcs[0]

    return h.sh.Handle(ctx, r)
}