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diff --git a/pkg/k8s.io/klog/README.md b/pkg/k8s.io/klog/README.md new file mode 100644 index 000000000..dcb75e33e --- /dev/null +++ b/pkg/k8s.io/klog/README.md @@ -0,0 +1,103 @@ +klog +==== + +klog is a permanent fork of https://github.com/golang/glog. + +## Why was klog created? + +The decision to create klog was one that wasn't made lightly, but it was necessary due to some +drawbacks that are present in [glog](https://github.com/golang/glog). Ultimately, the fork was created due to glog not being under active development; this can be seen in the glog README: + +> The code in this repo [...] is not itself under development + +This makes us unable to solve many use cases without a fork. The factors that contributed to needing feature development are listed below: + + * `glog` [presents a lot "gotchas"](https://github.com/kubernetes/kubernetes/issues/61006) and introduces challenges in containerized environments, all of which aren't well documented. + * `glog` doesn't provide an easy way to test logs, which detracts from the stability of software using it + * A long term goal is to implement a logging interface that allows us to add context, change output format, etc. + +Historical context is available here: + + * https://github.com/kubernetes/kubernetes/issues/61006 + * https://github.com/kubernetes/kubernetes/issues/70264 + * https://groups.google.com/forum/#!msg/kubernetes-sig-architecture/wCWiWf3Juzs/hXRVBH90CgAJ + * https://groups.google.com/forum/#!msg/kubernetes-dev/7vnijOMhLS0/1oRiNtigBgAJ + +---- + +How to use klog +=============== +- Replace imports for `"github.com/golang/glog"` with `"github.com/containers/podman/v4/pkg/k8s.io/klog"` +- Use `klog.InitFlags(nil)` explicitly for initializing global flags as we no longer use `init()` method to register the flags +- You can now use `log_file` instead of `log_dir` for logging to a single file (See `examples/log_file/usage_log_file.go`) +- If you want to redirect everything logged using klog somewhere else (say syslog!), you can use `klog.SetOutput()` method and supply a `io.Writer`. (See `examples/set_output/usage_set_output.go`) +- For more logging conventions (See [Logging Conventions](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/logging.md)) + +**NOTE**: please use the newer go versions that support semantic import versioning in modules, ideally go 1.11.4 or greater. + +### Coexisting with klog/v2 + +See [this example](examples/coexist_klog_v1_and_v2/) to see how to coexist with both klog/v1 and klog/v2. + +### Coexisting with glog +This package can be used side by side with glog. [This example](examples/coexist_glog/coexist_glog.go) shows how to initialize and synchronize flags from the global `flag.CommandLine` FlagSet. In addition, the example makes use of stderr as combined output by setting `alsologtostderr` (or `logtostderr`) to `true`. + +## Community, discussion, contribution, and support + +Learn how to engage with the Kubernetes community on the [community page](http://kubernetes.io/community/). + +You can reach the maintainers of this project at: + +- [Slack](https://kubernetes.slack.com/messages/klog) +- [Mailing List](https://groups.google.com/forum/#!forum/kubernetes-sig-architecture) + +### Code of conduct + +Participation in the Kubernetes community is governed by the [Kubernetes Code of Conduct](code-of-conduct.md). + +---- + +glog +==== + +Leveled execution logs for Go. + +This is an efficient pure Go implementation of leveled logs in the +manner of the open source C++ package + https://github.com/google/glog + +By binding methods to booleans it is possible to use the log package +without paying the expense of evaluating the arguments to the log. +Through the -vmodule flag, the package also provides fine-grained +control over logging at the file level. + +The comment from glog.go introduces the ideas: + + Package glog implements logging analogous to the Google-internal + C++ INFO/ERROR/V setup. It provides functions Info, Warning, + Error, Fatal, plus formatting variants such as Infof. It + also provides V-style logging controlled by the -v and + -vmodule=file=2 flags. + + Basic examples: + + glog.Info("Prepare to repel boarders") + + glog.Fatalf("Initialization failed: %s", err) + + See the documentation for the V function for an explanation + of these examples: + + if glog.V(2) { + glog.Info("Starting transaction...") + } + + glog.V(2).Infoln("Processed", nItems, "elements") + + +The repository contains an open source version of the log package +used inside Google. The master copy of the source lives inside +Google, not here. The code in this repo is for export only and is not itself +under development. Feature requests will be ignored. + +Send bug reports to golang-nuts@googlegroups.com. |