InitLogs overrides the klog default and turns contextual logging off. This
ensures that it is only enabled in Kubernetes commands that explicitly enable
it via a feature gate. A feature gate for it gets defined in
k8s.io/component-base/logs and is then used by Options.ValidateAndApply.
The effect of disabling contextual logging is very limited according to
benchmarks with kube-scheduler. The feature gets added anyway to satisfy the
PRR recommendation that features should be controllable.
The following commands have support for contextual logging:
- kube-apiserver
- kube-controller-manager
- kubelet
- kube-scheduler
- component-base/logs example
Supporting a feature gate check in ValidateAndApply and not in InitLogs is a
simplification: changing InitLogs to accept a FeatureGate would have implied
changing also component-base/cli.Run. This didn't seem worthwhile because
ValidateAndApply already covers the relevant commands.
When a Logger gets called directly via contextual logging, it has to do its own
verbosity check and therefore needs to know what the intended verbosity level
is.
This used to work previously because all verbosity checks were done in klog
before invoking the Logger.
We want to see in the output when keys are used more than once. This should be
fixed because parsing the log messages as JSON will only preserve one of the
values.
The name added to a logger via WithName only gets printed when a key is
chosen. "logger" is used as in the zap examples.
This becomes relevant once we support contextual logging. When logging through
klog the name is always empty.
Without these select statements, this test runs until the package-global
timeout and causes a panic. This change makes the test fail faster and
more legibly.
Signed-off-by: Steve Kuznetsov <skuznets@redhat.com>
Running logcheck as part of golangci-lint has several advantages:
- faster checking because finding files and parsing is shared
with other linters
- gets rid of the complex and buggy
hack/verify-structured-logging.sh (https://github.com/kubernetes/kubernetes/issues/106746)
- support for // nolint:logcheck
- works with Go 1.18
Some of these changes are cosmetic (repeatedly calling klog.V instead of
reusing the result), others address real issues:
- Logging a message only above a certain verbosity threshold without
recording that verbosity level (if klog.V().Enabled() { klog.Info... }):
this matters when using a logging backend which records the verbosity
level.
- Passing a format string with parameters to a logging function that
doesn't do string formatting.
All of these locations where found by the enhanced logcheck tool from
https://github.com/kubernetes/klog/pull/297.
In some cases it reports false positives, but those can be suppressed with
source code comments.
If a staging repo has .gitattributes files containing the `export-subst`
attribute ([example](b6c06a95d7/staging/src/k8s.io/client-go/pkg/version/.gitattributes)), then git expands the specified placeholders
when git archive is used.
When a published repo is downloaded from GitHub, GitHub does a
"git archive" under the hood. This means that the placeholders get
replaced by their relevant values. This type of "git archive"
application sometimes leads to undesired values. See the example below.
- In client-go, [line 59 in `pkg/version/base.go`](b6c06a95d7/staging/src/k8s.io/client-go/pkg/version/base.go (L59))
is expanded on a git archive. This line is needed as a fallback to
inject k8s version info for client-go when this info is not provided
via ldflags during builds.
- However, when k/client-go is vendored, the line gets expanded to _the
commit of the project vendoring client-go_ -- which is not helpful at
all! This also means that the vendored client-go will now contain
different (expanded) commit shas for different projects.
- To ensure reproducibility of source, this commit helps remove
the .gitattributes files before publishing the staging repos.
Additionally, when client-go is used as a library, we don't care about
the line being expanded to inject version info so it is also safe to
remove these files.
