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100 lines
2.3 KiB
Markdown
100 lines
2.3 KiB
Markdown
# go-pdebug
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[](https://travis-ci.org/lestrrat/go-pdebug)
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[](https://godoc.org/github.com/lestrrat/go-pdebug)
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Utilities for my print debugging fun. YMMV
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# WARNING
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This repository has been moved to [github.com/lestrrat-go/pdebug](https://github.com/lestrrat-go/pdebug). This repository exists so that libraries pointing to this URL will keep functioning, but this repository will NOT be updated in the future. Please use the new import path.
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# Synopsis
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# Description
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Building with `pdebug` declares a constant, `pdebug.Enabled` which you
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can use to easily compile in/out depending on the presence of a build tag.
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```go
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func Foo() {
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// will only be available if you compile with `-tags debug`
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if pdebug.Enabled {
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pdebug.Printf("Starting Foo()!
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}
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}
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```
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Note that using `github.com/lestrrat/go-pdebug` and `-tags debug` only
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compiles in the code. In order to actually show the debug trace, you need
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to specify an environment variable:
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```shell
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# For example, to show debug code during testing:
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PDEBUG_TRACE=1 go test -tags debug
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```
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If you want to forcefully show the trace (which is handy when you're
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debugging/testing), you can use the `debug0` tag instead:
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```shell
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go test -tags debug0
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```
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# Markers
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When you want to print debug a chain of function calls, you can use the
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`Marker` functions:
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```go
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func Foo() {
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if pdebug.Enabled {
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g := pdebug.Marker("Foo")
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defer g.End()
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}
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pdebug.Printf("Inside Foo()!")
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}
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```
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This will cause all of the `Printf` calls to automatically indent
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the output so it's visually easier to see where a certain trace log
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is being generated.
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By default it will print something like:
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```
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|DEBUG| START Foo
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|DEBUG| Inside Foo()!
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|DEBUG| END Foo (1.23μs)
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```
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If you want to automatically show the error value you are returning
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(but only if there is an error), you can use the `BindError` method:
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```go
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func Foo() (err error) {
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if pdebug.Enabled {
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g := pdebug.Marker("Foo").BindError(&err)
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defer g.End()
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}
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pdebug.Printf("Inside Foo()!")
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return errors.New("boo")
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}
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```
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This will print something like:
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```
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|DEBUG| START Foo
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|DEBUG| Inside Foo()!
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|DEBUG| END Foo (1.23μs): ERROR boo
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```
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