README.md

go-pdebug

Utilities for my print debugging fun. YMMV

WARNING

This repository has been moved to 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.

Synopsis

Description

Building with pdebug declares a constant, pdebug.Enabled which you can use to easily compile in/out depending on the presence of a build tag.

func Foo() {
  // will only be available if you compile with `-tags debug`
  if pdebug.Enabled {
    pdebug.Printf("Starting Foo()!
  }
}

Note that using github.com/lestrrat/go-pdebug and -tags debug only compiles in the code. In order to actually show the debug trace, you need to specify an environment variable:

# For example, to show debug code during testing:
PDEBUG_TRACE=1 go test -tags debug

If you want to forcefully show the trace (which is handy when you're debugging/testing), you can use the debug0 tag instead:

go test -tags debug0

Markers

When you want to print debug a chain of function calls, you can use the Marker functions:

func Foo() {
  if pdebug.Enabled {
    g := pdebug.Marker("Foo")
    defer g.End()
  }

  pdebug.Printf("Inside Foo()!")
}

This will cause all of the Printf calls to automatically indent the output so it's visually easier to see where a certain trace log is being generated.

By default it will print something like:

|DEBUG| START Foo
|DEBUG|   Inside Foo()!
|DEBUG| END Foo (1.23μs)

If you want to automatically show the error value you are returning (but only if there is an error), you can use the BindError method:

func Foo() (err error) {
  if pdebug.Enabled {
    g := pdebug.Marker("Foo").BindError(&err)
    defer g.End()
  }

  pdebug.Printf("Inside Foo()!")

  return errors.New("boo")
}

This will print something like:

|DEBUG| START Foo
|DEBUG|   Inside Foo()!
|DEBUG| END Foo (1.23μs): ERROR boo