diff options
Diffstat (limited to 'vendor/github.com/go-logr/logr/sloghandler.go')
-rw-r--r-- | vendor/github.com/go-logr/logr/sloghandler.go | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/vendor/github.com/go-logr/logr/sloghandler.go b/vendor/github.com/go-logr/logr/sloghandler.go new file mode 100644 index 000000000..82d1ba494 --- /dev/null +++ b/vendor/github.com/go-logr/logr/sloghandler.go @@ -0,0 +1,192 @@ +//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" +) + +type slogHandler struct { + // May be nil, in which case all logs get discarded. + sink LogSink + // Non-nil if sink is non-nil and implements SlogSink. + slogSink SlogSink + + // groupPrefix collects values from WithGroup calls. It gets added as + // prefix to value keys when handling a log record. + groupPrefix string + + // levelBias can be set when constructing the handler to influence the + // slog.Level of log records. A positive levelBias reduces the + // slog.Level value. slog has no API to influence this value after the + // handler got created, so it can only be set indirectly through + // Logger.V. + levelBias slog.Level +} + +var _ slog.Handler = &slogHandler{} + +// groupSeparator is used to concatenate WithGroup names and attribute keys. +const groupSeparator = "." + +// GetLevel is used for black box unit testing. +func (l *slogHandler) GetLevel() slog.Level { + return l.levelBias +} + +func (l *slogHandler) Enabled(_ context.Context, level slog.Level) bool { + return l.sink != nil && (level >= slog.LevelError || l.sink.Enabled(l.levelFromSlog(level))) +} + +func (l *slogHandler) Handle(ctx context.Context, record slog.Record) error { + if l.slogSink != nil { + // Only adjust verbosity level of log entries < slog.LevelError. + if record.Level < slog.LevelError { + record.Level -= l.levelBias + } + return l.slogSink.Handle(ctx, record) + } + + // No need to check for nil sink here because Handle will only be called + // when Enabled returned true. + + kvList := make([]any, 0, 2*record.NumAttrs()) + record.Attrs(func(attr slog.Attr) bool { + kvList = attrToKVs(attr, l.groupPrefix, kvList) + return true + }) + if record.Level >= slog.LevelError { + l.sinkWithCallDepth().Error(nil, record.Message, kvList...) + } else { + level := l.levelFromSlog(record.Level) + l.sinkWithCallDepth().Info(level, record.Message, kvList...) + } + return nil +} + +// sinkWithCallDepth adjusts the stack unwinding so that when Error or Info +// are called by Handle, code in slog gets skipped. +// +// This offset currently (Go 1.21.0) works for calls through +// slog.New(ToSlogHandler(...)). There's no guarantee that the call +// chain won't change. Wrapping the handler will also break unwinding. It's +// still better than not adjusting at all.... +// +// This cannot be done when constructing the handler because FromSlogHandler needs +// access to the original sink without this adjustment. A second copy would +// work, but then WithAttrs would have to be called for both of them. +func (l *slogHandler) sinkWithCallDepth() LogSink { + if sink, ok := l.sink.(CallDepthLogSink); ok { + return sink.WithCallDepth(2) + } + return l.sink +} + +func (l *slogHandler) WithAttrs(attrs []slog.Attr) slog.Handler { + if l.sink == nil || len(attrs) == 0 { + return l + } + + clone := *l + if l.slogSink != nil { + clone.slogSink = l.slogSink.WithAttrs(attrs) + clone.sink = clone.slogSink + } else { + kvList := make([]any, 0, 2*len(attrs)) + for _, attr := range attrs { + kvList = attrToKVs(attr, l.groupPrefix, kvList) + } + clone.sink = l.sink.WithValues(kvList...) + } + return &clone +} + +func (l *slogHandler) WithGroup(name string) slog.Handler { + if l.sink == nil { + return l + } + if name == "" { + // slog says to inline empty groups + return l + } + clone := *l + if l.slogSink != nil { + clone.slogSink = l.slogSink.WithGroup(name) + clone.sink = clone.slogSink + } else { + clone.groupPrefix = addPrefix(clone.groupPrefix, name) + } + return &clone +} + +// attrToKVs appends a slog.Attr to a logr-style kvList. It handle slog Groups +// and other details of slog. +func attrToKVs(attr slog.Attr, groupPrefix string, kvList []any) []any { + attrVal := attr.Value.Resolve() + if attrVal.Kind() == slog.KindGroup { + groupVal := attrVal.Group() + grpKVs := make([]any, 0, 2*len(groupVal)) + prefix := groupPrefix + if attr.Key != "" { + prefix = addPrefix(groupPrefix, attr.Key) + } + for _, attr := range groupVal { + grpKVs = attrToKVs(attr, prefix, grpKVs) + } + kvList = append(kvList, grpKVs...) + } else if attr.Key != "" { + kvList = append(kvList, addPrefix(groupPrefix, attr.Key), attrVal.Any()) + } + + return kvList +} + +func addPrefix(prefix, name string) string { + if prefix == "" { + return name + } + if name == "" { + return prefix + } + return prefix + groupSeparator + name +} + +// levelFromSlog adjusts the level by the logger's verbosity and negates it. +// It ensures that the result is >= 0. This is necessary because the result is +// passed to a LogSink and that API did not historically document whether +// levels could be negative or what that meant. +// +// Some example usage: +// +// logrV0 := getMyLogger() +// logrV2 := logrV0.V(2) +// slogV2 := slog.New(logr.ToSlogHandler(logrV2)) +// slogV2.Debug("msg") // =~ logrV2.V(4) =~ logrV0.V(6) +// slogV2.Info("msg") // =~ logrV2.V(0) =~ logrV0.V(2) +// slogv2.Warn("msg") // =~ logrV2.V(-4) =~ logrV0.V(0) +func (l *slogHandler) levelFromSlog(level slog.Level) int { + result := -level + result += l.levelBias // in case the original Logger had a V level + if result < 0 { + result = 0 // because LogSink doesn't expect negative V levels + } + return int(result) +} |