71 lines
2.0 KiB
Markdown
71 lines
2.0 KiB
Markdown
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Zapr :zap:
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==========
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A [logr](https://github.com/go-logr/logr) implementation using
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[Zap](https://github.com/uber-go/zap).
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Usage
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-----
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```go
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import (
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"fmt"
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"go.uber.org/zap"
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"github.com/go-logr/logr"
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"github.com/go-logr/zapr"
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)
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func main() {
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var log logr.Logger
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zapLog, err := zap.NewDevelopment()
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if err != nil {
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panic(fmt.Sprintf("who watches the watchmen (%v)?", err))
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}
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log = zapr.NewLogger(zapLog)
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log.Info("Logr in action!", "the answer", 42)
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}
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```
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Increasing Verbosity
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--------------------
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Zap uses semantically named levels for logging (`DebugLevel`, `InfoLevel`,
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`WarningLevel`, ...). Logr uses arbitrary numeric levels. By default logr's
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`V(0)` is zap's `InfoLevel` and `V(1)` is zap's `DebugLevel` (which is
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numerically -1). Zap does not have named levels that are more verbose than
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`DebugLevel`, but it's possible to fake it.
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As of zap v1.19.0 you can do something like the following in your setup code:
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```go
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zc := zap.NewProductionConfig()
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zc.Level = zap.NewAtomicLevelAt(zapcore.Level(-2))
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z, err := zc.Build()
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if err != nil {
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// ...
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}
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log := zapr.NewLogger(z)
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```
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Zap's levels get more verbose as the number gets smaller and more important and
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the number gets larger (`DebugLevel` is -1, `InfoLevel` is 0, `WarnLevel` is 1,
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and so on).
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The `-2` in the above snippet means that `log.V(2).Info()` calls will be active.
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`-3` would enable `log.V(3).Info()`, etc. Note that zap's levels are `int8`
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which means the most verbose level you can give it is -128. The zapr
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implementation will cap `V()` levels greater than 127 to 127, so setting the
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zap level to -128 really means "activate all logs".
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Implementation Details
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----------------------
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For the most part, concepts in Zap correspond directly with those in logr.
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Unlike Zap, all fields *must* be in the form of sugared fields --
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it's illegal to pass a strongly-typed Zap field in a key position to any
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of the logging methods (`Log`, `Error`).
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