Using global logger fails to bind values causing incorrect context values #3417
Comments
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提供一下最小复现呗？最小复现不是指几张截图，而是一个能完全运行的例子。你可以像这样操作：
比如说这就是一个最小复现： package main
import (
"context"
"github.com/go-kratos/kratos/v2/log"
)
func main() {
ctx := context.Background()
ctx = context.WithValue(ctx, traceIdKey{}, "123456")
global := log.GetLogger()
logger := log.WithContext(ctx, global)
// logger = log.With(logger, "traceId", TraceIdValue()) // 看后面的说明
helper := log.NewHelper(logger)
helper.Infow("msg", "用户登录", "user", "张三")
// 期望输出
// INFO traceId=123456 msg=用户登录 user=张三
// 实际输出
// INFO msg=用户登录 user=张三
}
type traceIdKey struct{}
// 看后面的说明
func TraceIdValue() log.Valuer {
return func(ctx context.Context) any {
return ctx.Value(traceIdKey{})
}
}这只是个例子。如果这个例子刚好能反映你的情况的话。那么问题就简单了。log 库并没有“能把 context 里所有 value 都打印出来” 的能力。想要从 context 里拿数据打印需要自己实现 logger 或者 valuer。比如例子中的 |
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@kvii package main
import (
"context"
"github.com/go-kratos/kratos/v2/log"
)
func main() {
ctx := context.Background()
ctx = context.WithValue(ctx, traceIdKey{}, "123456")
logger := log.DefaultLogger
newLogger := log.With(logger, "traceId", TraceIdValue())
log.SetLogger(newLogger) // setting logger with valuer as global
helper := log.NewHelper(newLogger)
helper.WithContext(ctx).Info("This prints the traceID correctly")
globalLogger := log.NewHelper(log.GetLogger()) // getting the global logger
globalLogger.WithContext(ctx).Info("This does not print the traceID")
// INFO traceId=123456 msg=This prints the traceID correctly
// INFO traceId=<nil> msg=This does not print the traceID
}
type traceIdKey struct{}
func TraceIdValue() log.Valuer {
return func(ctx context.Context) any {
return ctx.Value(traceIdKey{})
}
} |
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中文省流：因为 English version: package main
import (
"context"
"os"
"github.com/go-kratos/kratos/v2/log"
)
func main() {
l1 := log.NewStdLogger(os.Stderr) // *log.stdLogger
l2 := log.With(l1, "traceId", traceIdValuer) // *log.logger ctx=Background
log.SetLogger(l2) // log.global.Logger = l2
l3 := log.GetLogger() // log.global not l2 *log.loggerAppliance
ctx := context.TODO()
ctx = context.WithValue(ctx, traceIdKey{}, "123456")
// log.WithContext(ctx,l) only "merge" ctx when l is a *log.logger.
// and l3 is not.
l4 := log.WithContext(ctx, l3) // *log.logger (not l2) ctx=ctx
l4.Log(log.LevelInfo, "msg", "m")
// want:
// INFO traceId=123456 msg=m
// got:
// INFO traceId=<nil> msg=m
// solution: Let log.global be a place that only stores values, rather than a Logger.
}
type traceIdKey struct{}
var traceIdValuer log.Valuer = func(ctx context.Context) any {
return ctx.Value(traceIdKey{})
}Currently Lines 10 to 39 in 908e625 |
What happened:
Using a global logger fails to output correct values from the context. It instead creates a background context and fills data with empty values
What you expected to happen:
How to reproduce it (as minimally and precisely as possible):
Because the global logger is of type
loggerAppliance, usingWithContextcauses it to return a new instance without prefix and kvs. This causes the code to not bind values and causes the downstream logger to not have contextAnything else we need to know?:
Environment:
kratos -v):go version):cat /etc/os-release):The text was updated successfully, but these errors were encountered: