Add instructions to use different log levels for local and syslog

This commit adds instructions to the syslog readme about how to
send different log levels to local logging (`log.SetLevel`) and
syslog hook.

fixes #1369
This commit is contained in:
Tommaso Visconti 2023-02-17 10:03:12 +01:00
parent a448f8228b
commit 70234da9c3
2 changed files with 46 additions and 2 deletions

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@ -9,7 +9,7 @@ the last thing you want from your Logging library (again...).
This does not mean Logrus is dead. Logrus will continue to be maintained for This does not mean Logrus is dead. Logrus will continue to be maintained for
security, (backwards compatible) bug fixes, and performance (where we are security, (backwards compatible) bug fixes, and performance (where we are
limited by the interface). limited by the interface).
I believe Logrus' biggest contribution is to have played a part in today's I believe Logrus' biggest contribution is to have played a part in today's
widespread use of structured logging in Golang. There doesn't seem to be a widespread use of structured logging in Golang. There doesn't seem to be a
@ -99,7 +99,7 @@ time="2015-03-26T01:27:38-04:00" level=fatal method=github.com/sirupsen/arcticcr
``` ```
Note that this does add measurable overhead - the cost will depend on the version of Go, but is Note that this does add measurable overhead - the cost will depend on the version of Go, but is
between 20 and 40% in recent tests with 1.6 and 1.7. You can validate this in your between 20 and 40% in recent tests with 1.6 and 1.7. You can validate this in your
environment via benchmarks: environment via benchmarks:
``` ```
go test -bench=.*CallerTracing go test -bench=.*CallerTracing
``` ```
@ -317,6 +317,8 @@ log.SetLevel(log.InfoLevel)
It may be useful to set `log.Level = logrus.DebugLevel` in a debug or verbose It may be useful to set `log.Level = logrus.DebugLevel` in a debug or verbose
environment if your application has that. environment if your application has that.
Note: If you want different log levels for global (`log.SetLevel(...)`) and syslog logging, please check the [syslog hook README](hooks/syslog/README.md#different-log-levels-for-local-and-remote-logging).
#### Entries #### Entries
Besides the fields added with `WithField` or `WithFields` some fields are Besides the fields added with `WithField` or `WithFields` some fields are

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@ -37,3 +37,45 @@ func main() {
} }
} }
``` ```
### Different log levels for local and remote logging
By default `NewSyslogHook()` sends logs through the hook for all log levels. If you want to have
different log levels between local logging and syslog logging (i.e. respect the `priority` argument
passed to `NewSyslogHook()`), you need to implement the `logrus_syslog.SyslogHook` interface
overriding `Levels()` to return only the log levels you're interested on.
The following example shows how to log at **DEBUG** level for local logging and **WARN** level for
syslog logging:
```go
package main
import (
"log/syslog"
log "github.com/sirupsen/logrus"
logrus_syslog "github.com/sirupsen/logrus/hooks/syslog"
)
type customHook struct {
*logrus_syslog.SyslogHook
}
func (h *customHook) Levels() []log.Level {
return []log.Level{log.WarnLevel}
}
func main() {
log.SetLevel(log.DebugLevel)
hook, err := logrus_syslog.NewSyslogHook("tcp", "localhost:5140", syslog.LOG_WARNING, "myTag")
if err != nil {
panic(err)
}
log.AddHook(&customHook{hook})
//...
}
```