scheduler: contextual logging - WithName and WithValue #111155

This replaces all log calls through the global klog logger with a logger that gets passed in by the caller, either through an explicit parameter or the context. This makes it possible to produce more informative log output by adding WithName and/or WithValues instrumentation (not done yet!). It also makes "go test" failures more useful because the log output gets associated with the test which produced it. Usually, context is the more future-proof option. It has happened repeatedly throughout the life of this commit that a function that originally had no context later got changed in the master branch to accept for reasons unrelated to contextual logging. In several places, passing a context can replace passing a stop channel and then serves two purposes (access to logger and cancellation). But klog.FromContext has some overhead, so for simple functions a logger is passed.

This enables benchmarking with JSON selected as output.

This adds a prefix to each log entry that shows which operation and/or component produced the log entry (WithName) and ensures that relevant additional values, in particular the pod that gets scheduled, are always included (WithValues). This makes log entries easier to understand, in particular when multiple pods get scheduled in parallel. The downside is the constant overhead for these additional calls: they need to do some work, whether log entries will be printed or not.

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

scheduler: contextual logging - WithName and WithValue #111155

scheduler: contextual logging - WithName and WithValue #111155

Commits on Feb 16, 2023