slog: Handler.Enabled takes a context
Pass the Logger's context to its Handler's Enabled method,
so Enabled can use its values to make a decision.
Change-Id: Id1f77c5393a680dd4bfb462a5b6c9c9373e193ab
Reviewed-on: https://go-review.googlesource.com/c/exp/+/463935
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
diff --git a/slog/benchmarks/handlers.go b/slog/benchmarks/handlers.go
index ec40e58..0956929 100644
--- a/slog/benchmarks/handlers.go
+++ b/slog/benchmarks/handlers.go
@@ -7,6 +7,7 @@
// Handlers for benchmarking.
import (
+ "context"
"fmt"
"io"
"strconv"
@@ -31,7 +32,7 @@
return &fastTextHandler{w: w}
}
-func (h *fastTextHandler) Enabled(slog.Level) bool { return true }
+func (h *fastTextHandler) Enabled(context.Context, slog.Level) bool { return true }
func (h *fastTextHandler) Handle(r slog.Record) error {
buf := buffer.New()
@@ -116,7 +117,7 @@
return &asyncHandler{}
}
-func (*asyncHandler) Enabled(slog.Level) bool { return true }
+func (*asyncHandler) Enabled(context.Context, slog.Level) bool { return true }
func (h *asyncHandler) Handle(r slog.Record) error {
h.ringBuffer[h.next] = r.Clone()
@@ -134,8 +135,8 @@
type disabledHandler struct{}
-func (disabledHandler) Enabled(slog.Level) bool { return false }
-func (disabledHandler) Handle(slog.Record) error { panic("should not be called") }
+func (disabledHandler) Enabled(context.Context, slog.Level) bool { return false }
+func (disabledHandler) Handle(slog.Record) error { panic("should not be called") }
func (disabledHandler) WithAttrs([]slog.Attr) slog.Handler {
panic("disabledHandler: With unimplemented")
diff --git a/slog/example_level_handler_test.go b/slog/example_level_handler_test.go
index 5374447..194f8d5 100644
--- a/slog/example_level_handler_test.go
+++ b/slog/example_level_handler_test.go
@@ -5,6 +5,7 @@
package slog_test
import (
+ "context"
"os"
"golang.org/x/exp/slog"
@@ -29,7 +30,7 @@
// Enabled implements Handler.Enabled by reporting whether
// level is at least as large as h's level.
-func (h *LevelHandler) Enabled(level slog.Level) bool {
+func (h *LevelHandler) Enabled(_ context.Context, level slog.Level) bool {
return level >= h.level.Level()
}
diff --git a/slog/handler.go b/slog/handler.go
index 42edaf5..7c2a21b 100644
--- a/slog/handler.go
+++ b/slog/handler.go
@@ -5,6 +5,7 @@
package slog
import (
+ "context"
"fmt"
"io"
"strconv"
@@ -27,9 +28,11 @@
type Handler interface {
// Enabled reports whether the handler handles records at the given level.
// The handler ignores records whose level is lower.
- // Enabled is called early, before any arguments are processed,
+ // It is called early, before any arguments are processed,
// to save effort if the log event should be discarded.
- Enabled(Level) bool
+ // The Logger's context is passed so Enabled can use its values
+ // to make a decision. The context may be nil.
+ Enabled(context.Context, Level) bool
// Handle handles the Record.
// It will only be called if Enabled returns true.
@@ -76,7 +79,7 @@
}
}
-func (*defaultHandler) Enabled(l Level) bool {
+func (*defaultHandler) Enabled(_ context.Context, l Level) bool {
return l >= LevelInfo
}
diff --git a/slog/json_handler.go b/slog/json_handler.go
index c373936..991a149 100644
--- a/slog/json_handler.go
+++ b/slog/json_handler.go
@@ -5,6 +5,7 @@
package slog
import (
+ "context"
"encoding/json"
"errors"
"fmt"
@@ -42,7 +43,7 @@
// Enabled reports whether the handler handles records at the given level.
// The handler ignores records whose level is lower.
-func (h *JSONHandler) Enabled(level Level) bool {
+func (h *JSONHandler) Enabled(_ context.Context, level Level) bool {
return h.commonHandler.enabled(level)
}
diff --git a/slog/logger.go b/slog/logger.go
index 0f0c844..61dc933 100644
--- a/slog/logger.go
+++ b/slog/logger.go
@@ -45,7 +45,7 @@
}
func (w *handlerWriter) Write(buf []byte) (int, error) {
- if !w.h.Enabled(LevelInfo) {
+ if !w.h.Enabled(nil, LevelInfo) {
return 0, nil
}
var pc uintptr
@@ -141,7 +141,7 @@
// Enabled reports whether l emits log records at the given level.
func (l *Logger) Enabled(level Level) bool {
- return l.Handler().Enabled(level)
+ return l.Handler().Enabled(l.ctx, level)
}
// Log emits a log record with the current time and the given level and message.
diff --git a/slog/logger_test.go b/slog/logger_test.go
index 84380eb..766e123 100644
--- a/slog/logger_test.go
+++ b/slog/logger_test.go
@@ -137,7 +137,9 @@
h Handler
}
-func (h wrappingHandler) Enabled(level Level) bool { return h.h.Enabled(level) }
+func (h wrappingHandler) Enabled(ctx context.Context, level Level) bool {
+ return h.h.Enabled(ctx, level)
+}
func (h wrappingHandler) WithGroup(name string) Handler { return h.h.WithGroup(name) }
func (h wrappingHandler) WithAttrs(as []Attr) Handler { return h.h.WithAttrs(as) }
func (h wrappingHandler) Handle(r Record) error { return h.h.Handle(r) }
@@ -438,7 +440,7 @@
return nil
}
-func (*captureHandler) Enabled(Level) bool { return true }
+func (*captureHandler) Enabled(context.Context, Level) bool { return true }
func (c *captureHandler) WithAttrs(as []Attr) Handler {
c2 := *c
@@ -457,8 +459,8 @@
attrs []Attr
}
-func (d discardHandler) Enabled(Level) bool { return !d.disabled }
-func (discardHandler) Handle(Record) error { return nil }
+func (d discardHandler) Enabled(context.Context, Level) bool { return !d.disabled }
+func (discardHandler) Handle(Record) error { return nil }
func (d discardHandler) WithAttrs(as []Attr) Handler {
d.attrs = concat(d.attrs, as)
return d
diff --git a/slog/text_handler.go b/slog/text_handler.go
index a91e8ac..f0fbeeb 100644
--- a/slog/text_handler.go
+++ b/slog/text_handler.go
@@ -5,6 +5,7 @@
package slog
import (
+ "context"
"encoding"
"fmt"
"io"
@@ -39,7 +40,7 @@
// Enabled reports whether the handler handles records at the given level.
// The handler ignores records whose level is lower.
-func (h *TextHandler) Enabled(level Level) bool {
+func (h *TextHandler) Enabled(_ context.Context, level Level) bool {
return h.commonHandler.enabled(level)
}
