Proposal: provide a SetLog() func

[aanm]

Is it possible to provide a SetLog() in the packages? For example, I'm using 3 cache.NewInformer to watch for changes on 3 different resources, but if, for whatever reason, the connection between the client and the apiserver doesn't exist, I have this error messages in my log:

ERROR: logging before flag.Parse: E1018 14:16:07.808569    5156 reflector.go:214] k8s.io/client-go/1.5/tools/cache/reflector.go:109: Failed to list *v1.Endpoints: Get http://192.168.33.11:8080/api/v1/endpoints?resourceVersion=0: dial tcp 192.168.33.11:8080: getsockopt: connection refused
ERROR: logging before flag.Parse: E1018 14:16:08.809443    5156 reflector.go:214] k8s.io/client-go/1.5/tools/cache/reflector.go:109: Failed to list *v1beta1.NetworkPolicy: Get http://192.168.33.11:8080/apis/extensions/v1beta1/networkpolicies?resourceVersion=0: dial tcp 192.168.33.11:8080: getsockopt: connection refused
ERROR: logging before flag.Parse: E1018 14:16:08.809458    5156 reflector.go:214] k8s.io/client-go/1.5/tools/cache/reflector.go:109: Failed to list *v1.Service: Get http://192.168.33.11:8080/api/v1/services?resourceVersion=0: dial tcp 192.168.33.11:8080: getsockopt: connection refused
ERROR: logging before flag.Parse: E1018 14:16:08.809526    5156 reflector.go:214] k8s.io/client-go/1.5/tools/cache/reflector.go:109: Failed to list *v1.Endpoints: Get http://192.168.33.11:8080/api/v1/endpoints?resourceVersion=0: dial tcp 192.168.33.11:8080: getsockopt: connection refused
ERROR: logging before flag.Parse: E1018 14:16:09.811722    5156 reflector.go:214] k8s.io/client-go/1.5/tools/cache/reflector.go:109: Failed to list *v1beta1.NetworkPolicy: Get http://192.168.33.11:8080/apis/extensions/v1beta1/networkpolicies?resourceVersion=0: dial tcp 192.168.33.11:8080: getsockopt: connection refused
ERROR: logging before flag.Parse: E1018 14:16:09.811733    5156 reflector.go:214] k8s.io/client-go/1.5/tools/cache/reflector.go:109: Failed to list *v1.Endpoints: Get http://192.168.33.11:8080/api/v1/endpoints?resourceVersion=0: dial tcp 192.168.33.11:8080: getsockopt: connection refused
ERROR: logging before flag.Parse: E1018 14:16:09.811733    5156 reflector.go:214] k8s.io/client-go/1.5/tools/cache/reflector.go:109: Failed to list *v1.Service: Get http://192.168.33.11:8080/api/v1/services?resourceVersion=0: dial tcp 192.168.33.11:8080: getsockopt: connection refused

I would like to at least change the layout to be the same as my logs or/and silent the log messages until I get a new kubernetes connection.

[jimmidyson]

Would love to have a proper log interface & be able to provide an impl that the client could use. glog is a bit invasive here.

[ae6rt]

Thank you for this k8s client. It's very helpful.

Do you have any advice around suppressing glog's hoisting of its command line flags into the help output of tools that use the k8s client.

For example, those flags whose descriptions are not decorated with "MyApp" are coming from glog's init function: https://github.com/golang/glog/blob/master/glog.go#L398

Usage of build/dist/darwin/myapp:
  -alsologtostderr
    	log to standard error as well as files
  -config string
    	MyApp: Config file that points to the K8S master. (default "./config")
  -log_backtrace_at value
    	when logging hits line file:N, emit a stack trace
  -log_dir string
    	If non-empty, write log files in this directory
  -logtostderr
    	log to standard error instead of files
  -reload
    	MyApp: Send the initial system state read from K8S to the load balancer. (default true)
  -stderrthreshold value
    	logs at or above this threshold go to stderr
  -v value
    	log level for V logs
  -vmodule value
    	comma-separated list of pattern=N settings for file-filtered logging

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[DavidHuie]

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[DavidHuie]

I would also appreciate having this feature. We're currently building tooling around client-go without using glog, so we would love to have the ability to override it.

[deads2k]

If we undertake the effort to switch logging frameworks, (It's not just going to be client-go), we need to have

1. flag compatibility - there are numerous "real" deployments using these. Make the optional to register.
2. dynamic package log level changes
3. logging formatter pluggability (one size does NOT fit all)
4. logging handler pluggability (different sinks exist and have value)
5. logging filter pluggability (dynamic and per project filtering needs exist)
6. glog compatibility desired.

@lavalamp @eparis @bparees you've also dealt with our logging shortcomings, other things to add to the list?

I'm disinclined to undertake the effort of a replacement that didn't address those requirements.

[bparees]

@deads2k that covers my wishlist, anyway. I suppose rate limiting or de-duping might be nice options as well, but not must haves.

[deads2k]

@deads2k that covers my wishlist, anyway. I suppose rate limiting or de-duping might be nice options as well, but not must haves.

I agree those are nice to have. I think that given pluggable filters and handlers it is possible to build de-duping and rate limiting. Given pieces to build them, I won't block progress on not having them.

[liggitt]

logging formatter pluggability (one size does NOT fit all)

If you're wanting structured logs, then you really have to replace all usage of glog (even from our dependencies) in order to be useful ("almost all JSON" log output doesn't really do much good)

logging handler pluggability (different sinks exist and have value)

same comment about logger usage by dependencies

[deads2k]

logging formatter pluggability (one size does NOT fit all)
If you're wanting structured logs, then you really have to replace all usage of glog (even from our dependencies) in order to be useful ("almost all JSON" log output doesn't really do much good)

logging handler pluggability (different sinks exist and have value)
same comment about logger usage by dependencies

The same sort of argument would apply to fmt and to capnslog and whatever else other libraries do. Formatting of most messages does help significantly (ie: I get <package>.<file> in 90% of messages) . The same applies for handlers (I get a well present systemd log), getting 90% working really helps.

Mixing log4j and jsr47 doesn't work perfectly, but you don't have to have perfect coherence for big gains.

[luxalpa]

same comment about logger usage by dependencies

In our projects, we have more that 80 services with countless of dependencies and so far we had no problem with structured logging (except from k8s/client-go). I found that usually dependencies just use the log.Logger interface for logging.

Could you make a list of dependencies that use glog?

[lavalamp]

Sadly it does seem reasonable to want glog to not be mandatory to use the client. This would be a fairly large effort, though. We'd have to define a new logging interface & provide a glog implementation which gives zero difference from today. (glog's interface is not easy (or possible, even?) to reimplement due to the .V(). pattern--I consider it a go language defect :( )

If we had an interface and a 100% compatible glog implementation, we could slowly roll changes out. But it's a lot of effort.

[sttts]

Technically you can reimplement github.com/golang/glog using another library, place the wrapper in your vendor/ dir and make e.g. golang/dep to point to your wrapper:

[[constraint]]
  name = "github.com/golang/glog"
  source = "https://github.com/yourorg/glog-wrapper"

This way you won't hit the "go language defect" @lavalamp is referring to and client-go will use your logging library without any code change.

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[aanm]

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[aanm]

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[fiunchinho]

does anyone know a workaround for this? I'd like to set the format for glog logs, or disable it all together.

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[aanm]

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[aanm]

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[DingGGu]

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[aanm]

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[coryrc]

Since client-go now uses klog, doesn't klog.SetLogger() fulfill this proposal?

https://github.com/kubernetes/klog/blob/8422fac62d1e961e89426ffb5ae3a07f2d0bcca2/klog.go#L776

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[k8s-ci-robot]

@fejta-bot: Closing this issue.

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[kishoregv]

Since client-go now uses klog, doesn't klog.SetLogger() fulfill this proposal?

https://github.com/kubernetes/klog/blob/8422fac62d1e961e89426ffb5ae3a07f2d0bcca2/klog.go#L776

To be able to use klog.SetLogger() client-go needs to start using k8s.io/klog/v2

[kishoregv]

/remove-lifecycle rotten