diff options
Diffstat (limited to 'vendor/github.com/go-logr/logr/slogr.go')
-rw-r--r-- | vendor/github.com/go-logr/logr/slogr.go | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/vendor/github.com/go-logr/logr/slogr.go b/vendor/github.com/go-logr/logr/slogr.go new file mode 100644 index 000000000..28a83d024 --- /dev/null +++ b/vendor/github.com/go-logr/logr/slogr.go @@ -0,0 +1,100 @@ +//go:build go1.21 +// +build go1.21 + +/* +Copyright 2023 The logr Authors. + +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 logr + +import ( + "context" + "log/slog" +) + +// FromSlogHandler returns a Logger which writes to the slog.Handler. +// +// The logr verbosity level is mapped to slog levels such that V(0) becomes +// slog.LevelInfo and V(4) becomes slog.LevelDebug. +func FromSlogHandler(handler slog.Handler) Logger { + if handler, ok := handler.(*slogHandler); ok { + if handler.sink == nil { + return Discard() + } + return New(handler.sink).V(int(handler.levelBias)) + } + return New(&slogSink{handler: handler}) +} + +// ToSlogHandler returns a slog.Handler which writes to the same sink as the Logger. +// +// The returned logger writes all records with level >= slog.LevelError as +// error log entries with LogSink.Error, regardless of the verbosity level of +// the Logger: +// +// logger := <some Logger with 0 as verbosity level> +// slog.New(ToSlogHandler(logger.V(10))).Error(...) -> logSink.Error(...) +// +// The level of all other records gets reduced by the verbosity +// level of the Logger and the result is negated. If it happens +// to be negative, then it gets replaced by zero because a LogSink +// is not expected to handled negative levels: +// +// slog.New(ToSlogHandler(logger)).Debug(...) -> logger.GetSink().Info(level=4, ...) +// slog.New(ToSlogHandler(logger)).Warning(...) -> logger.GetSink().Info(level=0, ...) +// slog.New(ToSlogHandler(logger)).Info(...) -> logger.GetSink().Info(level=0, ...) +// slog.New(ToSlogHandler(logger.V(4))).Info(...) -> logger.GetSink().Info(level=4, ...) +func ToSlogHandler(logger Logger) slog.Handler { + if sink, ok := logger.GetSink().(*slogSink); ok && logger.GetV() == 0 { + return sink.handler + } + + handler := &slogHandler{sink: logger.GetSink(), levelBias: slog.Level(logger.GetV())} + if slogSink, ok := handler.sink.(SlogSink); ok { + handler.slogSink = slogSink + } + return handler +} + +// SlogSink is an optional interface that a LogSink can implement to support +// logging through the slog.Logger or slog.Handler APIs better. It then should +// also support special slog values like slog.Group. When used as a +// slog.Handler, the advantages are: +// +// - stack unwinding gets avoided in favor of logging the pre-recorded PC, +// as intended by slog +// - proper grouping of key/value pairs via WithGroup +// - verbosity levels > slog.LevelInfo can be recorded +// - less overhead +// +// Both APIs (Logger and slog.Logger/Handler) then are supported equally +// well. Developers can pick whatever API suits them better and/or mix +// packages which use either API in the same binary with a common logging +// implementation. +// +// This interface is necessary because the type implementing the LogSink +// interface cannot also implement the slog.Handler interface due to the +// different prototype of the common Enabled method. +// +// An implementation could support both interfaces in two different types, but then +// additional interfaces would be needed to convert between those types in FromSlogHandler +// and ToSlogHandler. +type SlogSink interface { + LogSink + + Handle(ctx context.Context, record slog.Record) error + WithAttrs(attrs []slog.Attr) SlogSink + WithGroup(name string) SlogSink +} |