github.com/lestrrat-go/pdebug

Utilities for my print debugging fun. YMMV

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.

In the following example, the clause within pdebug.Enabled is compiled out because it is a constant boolean.

import "github.com/lestrrat-go/pdebug/v3"

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

To enable the prints, simply compile with the debug tag.

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.FuncMarker()
    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| 123456789.0000 START github.com/lestrrat-go/pdebug.Foo
|DEBUG| 123456789.0000   Inside Foo()!
|DEBUG| 123456789.0000 END   github.com/lestrrat-go/pdebug.Foo (elapsed=1.23s)

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:

import "github.com/lestrrat-go/pdebug/v3"

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

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

  return errors.New("boo")
}

This will print something like:

|DEBUG| 123456789.0000 START github.com/lestrrat-go/pdebug.Foo
|DEBUG| 123456789.0000   Inside Foo()!
|DEBUG| 123456789.0000 END   github.com/lestrrat-go/pdebug.Foo (elapsed=1.23s, rror=boo)