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Merge pull request #92554 from serathius/klog-upgrade

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Update k8s.io/klog to v2.2.0
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Kubernetes Prow Robot
2020-07-01 23:13:27 -07:00
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parent 343995e8e2 e72521e1d7
commit bd60f0787e
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vendor/github.com/go-logr/logr/README.md generated vendored
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@@ -1,9 +1,9 @@
# A more minimal logging API for Go
Before you consider this package, please read [this blog post by the inimitable
Dave Cheney](http://dave.cheney.net/2015/11/05/lets-talk-about-logging). I
really appreciate what he has to say, and it largely aligns with my own
experiences. Too many choices of levels means inconsistent logs.
Before you consider this package, please read [this blog post by the
inimitable Dave Cheney][warning-makes-no-sense]. I really appreciate what
he has to say, and it largely aligns with my own experiences. Too many
choices of levels means inconsistent logs.
This package offers a purely abstract interface, based on these ideas but with
a few twists. Code can depend on just this interface and have the actual
@@ -31,6 +31,151 @@ may feel very similar, but the primary difference is the lack of semantics.
Because verbosity is a numerical value, it's safe to assume that an app running
with higher verbosity means more (and less important) logs will be generated.
This is a BETA grade API. I have implemented it for
[glog](https://godoc.org/github.com/golang/glog). Until there is a significant
2nd implementation, I don't really know how it will change.
This is a BETA grade API.
There are implementations for the following logging libraries:
- **github.com/google/glog**: [glogr](https://github.com/go-logr/glogr)
- **k8s.io/klog**: [klogr](https://git.k8s.io/klog/klogr)
- **go.uber.org/zap**: [zapr](https://github.com/go-logr/zapr)
- **log** (the Go standard library logger):
[stdr](https://github.com/go-logr/stdr)
- **github.com/sirupsen/logrus**: [logrusr](https://github.com/bombsimon/logrusr)
# FAQ
## Conceptual
## Why structured logging?
- **Structured logs are more easily queriable**: Since you've got
key-value pairs, it's much easier to query your structured logs for
particular values by filtering on the contents of a particular key --
think searching request logs for error codes, Kubernetes reconcilers for
the name and namespace of the reconciled object, etc
- **Structured logging makes it easier to have cross-referencable logs**:
Similarly to searchability, if you maintain conventions around your
keys, it becomes easy to gather all log lines related to a particular
concept.
- **Structured logs allow better dimensions of filtering**: if you have
structure to your logs, you've got more precise control over how much
information is logged -- you might choose in a particular configuration
to log certain keys but not others, only log lines where a certain key
matches a certain value, etc, instead of just having v-levels and names
to key off of.
- **Structured logs better represent structured data**: sometimes, the
data that you want to log is inherently structured (think tuple-link
objects). Structured logs allow you to preserve that structure when
outputting.
## Why V-levels?
**V-levels give operators an easy way to control the chattiness of log
operations**. V-levels provide a way for a given package to distinguish
the relative importance or verbosity of a given log message. Then, if
a particular logger or package is logging too many messages, the user
of the package can simply change the v-levels for that library.
## Why not more named levels, like Warning?
Read [Dave Cheney's post][warning-makes-no-sense]. Then read [Differences
from Dave's ideas](#differences-from-daves-ideas).
## Why not allow format strings, too?
**Format strings negate many of the benefits of structured logs**:
- They're not easily searchable without resorting to fuzzy searching,
regular expressions, etc
- They don't store structured data well, since contents are flattened into
a string
- They're not cross-referencable
- They don't compress easily, since the message is not constant
(unless you turn positional parameters into key-value pairs with numerical
keys, at which point you've gotten key-value logging with meaningless
keys)
## Practical
## Why key-value pairs, and not a map?
Key-value pairs are *much* easier to optimize, especially around
allocations. Zap (a structured logger that inspired logr's interface) has
[performance measurements](https://github.com/uber-go/zap#performance)
that show this quite nicely.
While the interface ends up being a little less obvious, you get
potentially better performance, plus avoid making users type
`map[string]string{}` every time they want to log.
## What if my V-levels differ between libraries?
That's fine. Control your V-levels on a per-logger basis, and use the
`WithName` function to pass different loggers to different libraries.
Generally, you should take care to ensure that you have relatively
consistent V-levels within a given logger, however, as this makes deciding
on what verbosity of logs to request easier.
## But I *really* want to use a format string!
That's not actually a question. Assuming your question is "how do
I convert my mental model of logging with format strings to logging with
constant messages":
1. figure out what the error actually is, as you'd write in a TL;DR style,
and use that as a message
2. For every place you'd write a format specifier, look to the word before
it, and add that as a key value pair
For instance, consider the following examples (all taken from spots in the
Kubernetes codebase):
- `klog.V(4).Infof("Client is returning errors: code %v, error %v",
responseCode, err)` becomes `logger.Error(err, "client returned an
error", "code", responseCode)`
- `klog.V(4).Infof("Got a Retry-After %ds response for attempt %d to %v",
seconds, retries, url)` becomes `logger.V(4).Info("got a retry-after
response when requesting url", "attempt", retries, "after
seconds", seconds, "url", url)`
If you *really* must use a format string, place it as a key value, and
call `fmt.Sprintf` yourself -- for instance, `log.Printf("unable to
reflect over type %T")` becomes `logger.Info("unable to reflect over
type", "type", fmt.Sprintf("%T"))`. In general though, the cases where
this is necessary should be few and far between.
## How do I choose my V-levels?
This is basically the only hard constraint: increase V-levels to denote
more verbose or more debug-y logs.
Otherwise, you can start out with `0` as "you always want to see this",
`1` as "common logging that you might *possibly* want to turn off", and
`10` as "I would like to performance-test your log collection stack".
Then gradually choose levels in between as you need them, working your way
down from 10 (for debug and trace style logs) and up from 1 (for chattier
info-type logs).
## How do I choose my keys
- make your keys human-readable
- constant keys are generally a good idea
- be consistent across your codebase
- keys should naturally match parts of the message string
While key names are mostly unrestricted (and spaces are acceptable),
it's generally a good idea to stick to printable ascii characters, or at
least match the general character set of your log lines.
[warning-makes-no-sense]: http://dave.cheney.net/2015/11/05/lets-talk-about-logging

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vendor/github.com/go-logr/logr/go.mod generated vendored Normal file
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module github.com/go-logr/logr
go 1.14

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vendor/github.com/go-logr/logr/logr.go generated vendored
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/*
Copyright 2019 The logr Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
// Package logr defines abstract interfaces for logging. Packages can depend on
// these interfaces and callers can implement logging in whatever way is
// appropriate.
@@ -13,22 +29,22 @@
//
// Usage
//
// Logging is done using a Logger. Loggers can have name prefixes and named values
// attached, so that all log messages logged with that Logger have some base context
// associated.
// Logging is done using a Logger. Loggers can have name prefixes and named
// values attached, so that all log messages logged with that Logger have some
// base context associated.
//
// The term "key" is used to refer to the name associated with a particular value, to
// disambiguate it from the general Logger name.
// The term "key" is used to refer to the name associated with a particular
// value, to disambiguate it from the general Logger name.
//
// For instance, suppose we're trying to reconcile the state of an object, and we want
// to log that we've made some decision.
// For instance, suppose we're trying to reconcile the state of an object, and
// we want to log that we've made some decision.
//
// With the traditional log package, we might write
// With the traditional log package, we might write:
// log.Printf(
// "decided to set field foo to value %q for object %s/%s",
// targetValue, object.Namespace, object.Name)
//
// With logr's structured logging, we'd write
// With logr's structured logging, we'd write:
// // elsewhere in the file, set up the logger to log with the prefix of "reconcilers",
// // and the named value target-type=Foo, for extra context.
// log := mainLogger.WithName("reconcilers").WithValues("target-type", "Foo")
@@ -36,72 +52,95 @@
// // later on...
// log.Info("setting field foo on object", "value", targetValue, "object", object)
//
// Depending on our logging implementation, we could then make logging decisions based on field values
// (like only logging such events for objects in a certain namespace), or copy the structured
// information into a structured log store.
// Depending on our logging implementation, we could then make logging decisions
// based on field values (like only logging such events for objects in a certain
// namespace), or copy the structured information into a structured log store.
//
// For logging errors, Logger has a method called Error. Suppose we wanted to log an
// error while reconciling. With the traditional log package, we might write
// For logging errors, Logger has a method called Error. Suppose we wanted to
// log an error while reconciling. With the traditional log package, we might
// write:
// log.Errorf("unable to reconcile object %s/%s: %v", object.Namespace, object.Name, err)
//
// With logr, we'd instead write
// With logr, we'd instead write:
// // assuming the above setup for log
// log.Error(err, "unable to reconcile object", "object", object)
//
// This functions similarly to:
// log.Info("unable to reconcile object", "error", err, "object", object)
//
// However, it ensures that a standard key for the error value ("error") is used across all
// error logging. Furthermore, certain implementations may choose to attach additional
// information (such as stack traces) on calls to Error, so it's preferred to use Error
// to log errors.
// However, it ensures that a standard key for the error value ("error") is used
// across all error logging. Furthermore, certain implementations may choose to
// attach additional information (such as stack traces) on calls to Error, so
// it's preferred to use Error to log errors.
//
// Parts of a log line
//
// Each log message from a Logger has four types of context:
// logger name, log verbosity, log message, and the named values.
//
// The Logger name constists of a series of name "segments" added by successive calls to WithName.
// These name segments will be joined in some way by the underlying implementation. It is strongly
// reccomended that name segements contain simple identifiers (letters, digits, and hyphen), and do
// not contain characters that could muddle the log output or confuse the joining operation (e.g.
// whitespace, commas, periods, slashes, brackets, quotes, etc).
// The Logger name constists of a series of name "segments" added by successive
// calls to WithName. These name segments will be joined in some way by the
// underlying implementation. It is strongly reccomended that name segements
// contain simple identifiers (letters, digits, and hyphen), and do not contain
// characters that could muddle the log output or confuse the joining operation
// (e.g. whitespace, commas, periods, slashes, brackets, quotes, etc).
//
// Log verbosity represents how little a log matters. Level zero, the default, matters most.
// Increasing levels matter less and less. Try to avoid lots of different verbosity levels,
// and instead provide useful keys, logger names, and log messages for users to filter on.
// It's illegal to pass a log level below zero.
// Log verbosity represents how little a log matters. Level zero, the default,
// matters most. Increasing levels matter less and less. Try to avoid lots of
// different verbosity levels, and instead provide useful keys, logger names,
// and log messages for users to filter on. It's illegal to pass a log level
// below zero.
//
// The log message consists of a constant message attached to the the log line. This
// should generally be a simple description of what's occuring, and should never be a format string.
// The log message consists of a constant message attached to the the log line.
// This should generally be a simple description of what's occuring, and should
// never be a format string.
//
// Variable information can then be attached using named values (key/value pairs). Keys are arbitrary
// strings, while values may be any Go value.
// Variable information can then be attached using named values (key/value
// pairs). Keys are arbitrary strings, while values may be any Go value.
//
// Key Naming Conventions
//
// While users are generally free to use key names of their choice, it's generally best to avoid
// using the following keys, as they're frequently used by implementations:
// Keys are not strictly required to conform to any specification or regex, but
// it is recommended that they:
// * be human-readable and meaningful (not auto-generated or simple ordinals)
// * be constant (not dependent on input data)
// * contain only printable characters
// * not contain whitespace or punctuation
//
// These guidelines help ensure that log data is processed properly regardless
// of the log implementation. For example, log implementations will try to
// output JSON data or will store data for later database (e.g. SQL) queries.
//
// While users are generally free to use key names of their choice, it's
// generally best to avoid using the following keys, as they're frequently used
// by implementations:
//
// - `"error"`: the underlying error value in the `Error` method.
// - `"stacktrace"`: the stack trace associated with a particular log line or error
// (often from the `Error` message).
// - `"caller"`: the calling information (file/line) of a particular log line.
// - `"msg"`: the log message.
// - `"error"`: the underlying error value in the `Error` method.
// - `"level"`: the log level.
// - `"logger"`: the name of the associated logger.
// - `"msg"`: the log message.
// - `"stacktrace"`: the stack trace associated with a particular log line or
// error (often from the `Error` message).
// - `"ts"`: the timestamp for a log line.
//
// Implementations are encouraged to make use of these keys to represent the above
// concepts, when neccessary (for example, in a pure-JSON output form, it would be
// necessary to represent at least message and timestamp as ordinary named values).
// Implementations are encouraged to make use of these keys to represent the
// above concepts, when neccessary (for example, in a pure-JSON output form, it
// would be necessary to represent at least message and timestamp as ordinary
// named values).
package logr
// TODO: consider adding back in format strings if they're really needed
// TODO: consider other bits of zap/zapcore functionality like ObjectMarshaller (for arbitrary objects)
// TODO: consider other bits of glog functionality like Flush, InfoDepth, OutputStats
// InfoLogger represents the ability to log non-error messages, at a particular verbosity.
type InfoLogger interface {
// Logger represents the ability to log messages, both errors and not.
type Logger interface {
// Enabled tests whether this Logger is enabled. For example, commandline
// flags might be used to set the logging verbosity and disable some info
// logs.
Enabled() bool
// Info logs a non-error message with the given key/value pairs as context.
//
// The msg argument should be used to add some constant description to
@@ -110,19 +149,6 @@ type InfoLogger interface {
// keys and arbitrary values.
Info(msg string, keysAndValues ...interface{})
// Enabled tests whether this InfoLogger is enabled. For example,
// commandline flags might be used to set the logging verbosity and disable
// some info logs.
Enabled() bool
}
// Logger represents the ability to log messages, both errors and not.
type Logger interface {
// All Loggers implement InfoLogger. Calling InfoLogger methods directly on
// a Logger value is equivalent to calling them on a V(0) InfoLogger. For
// example, logger.Info() produces the same result as logger.V(0).Info.
InfoLogger
// Error logs an error, with the given message and key/value pairs as context.
// It functions similarly to calling Info with the "error" named value, but may
// have unique behavior, and should be preferred for logging errors (see the
@@ -133,10 +159,11 @@ type Logger interface {
// triggered this log line, if present.
Error(err error, msg string, keysAndValues ...interface{})
// V returns an InfoLogger value for a specific verbosity level. A higher
// verbosity level means a log message is less important. It's illegal to
// pass a log level less than zero.
V(level int) InfoLogger
// V returns an Logger value for a specific verbosity level, relative to
// this Logger. In other words, V values are additive. V higher verbosity
// level means a log message is less important. It's illegal to pass a log
// level less than zero.
V(level int) Logger
// WithValues adds some key-value pairs of context to a logger.
// See Info for documentation on how key/value pairs work.