deps: convert zap to slog (#2825)

internal/logger/levelhandler.go

@@ -0,0 +1,57 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package logger
+
+import (
+	"context"
+	"log/slog"
+)
+
+// LevelHandler copied from the official LevelHandler example in the slog package documentation.
+
+// LevelHandler wraps a Handler with an Enabled method
+// that returns false for levels below a minimum.
+type LevelHandler struct {
+	level   slog.Leveler
+	handler slog.Handler
+}
+
+// NewLevelHandler returns a LevelHandler with the given level.
+// All methods except Enabled delegate to h.
+func NewLevelHandler(level slog.Leveler, h slog.Handler) *LevelHandler {
+	// Optimization: avoid chains of LevelHandlers.
+	if lh, ok := h.(*LevelHandler); ok {
+		h = lh.Handler()
+	}
+	return &LevelHandler{level, h}
+}
+
+// Enabled implements Handler.Enabled by reporting whether
+// level is at least as large as h's level.
+func (h *LevelHandler) Enabled(_ context.Context, level slog.Level) bool {
+	return level >= h.level.Level()
+}
+
+// Handle implements Handler.Handle.
+func (h *LevelHandler) Handle(ctx context.Context, r slog.Record) error {
+	return h.handler.Handle(ctx, r)
+}
+
+// WithAttrs implements Handler.WithAttrs.
+func (h *LevelHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	return NewLevelHandler(h.level, h.handler.WithAttrs(attrs))
+}
+
+// WithGroup implements Handler.WithGroup.
+func (h *LevelHandler) WithGroup(name string) slog.Handler {
+	return NewLevelHandler(h.level, h.handler.WithGroup(name))
+}
+
+// Handler returns the Handler wrapped by h.
+func (h *LevelHandler) Handler() slog.Handler {
+	return h.handler
+}