Ruby on Rails: debugging rake tasks

Question

When I write debugger it does not start:

NoMethodError: undefined method `run_init_script' for Debugger:Module
from /usr/local/lib/ruby/gems/1.8/gems/ruby-debug-base-0.10.3/lib/ruby-debug-base.rb:239:in `debugger'
from (irb):4

If I run rake my:task --debugger,it returns me to console immediately. How is it possible to debug rake tasks?

Balmung

Check this if you want to debug from Rubymine. https://mcmap.net/q/390518/-rubymine-debugger-with-rake – Oscar

Answer 1

I found the solution.

$ gem install ruby-debug
$ ruby-debug rake my:task

or on some systems

$ rdebug rake my:task

Balmung

Really though you shouldn't be doing large amounts of logic in a rake task. Most of my rake tasks are one-liners that call a method on a model which is then fully covered with tests. – Torrie

I am doing spider based on mechanize and I need debug some lines. All them in methods and not covered by tests yet. Thank you for the reply. – Balmung

@rspeicher, it's useful if you have a seed task – Efficacy

on my system is rdebug instead of ruby-debug – Efficacy

TIP: Add in the beginning Debugger.settings[:autoeval] = true that will cause the typical rails behavior where everything you type runs scoped to the self where you put the debugger call. – Lovelady

This didn't work for me in Ruby 1.9. See my answer for what did work for me in Ruby 1.9. – Rick

Answer 2

Andrey Kouznetsov's answer didn't work for me using Ruby 1.9.3. The ruby-debug gem doesn't seem to support Ruby 1.9. I had to use the debugger gem: https://github.com/cldwalker/debugger.

1. Add gem 'debugger' to my Gemfile's development group.
2. Run bundle.
3. Add require 'debugger' to the top of my rake task.
4. Add a call to debugger where I wanted a breakpoint in my rake task.
5. Run the rake task normally from the command line, e.g.: rake my:task.

Rick

Another option instead of putting require 'debugger' at the top is to put inline require 'debugger'; debugger. That way, when you delete the debugger statements, you won't forget to delete the require. – Ekg

Answer 3

I highly recommend pry for this

bundle install pry
require 'pry'
rake ...

In your rake task file:

binding.pry 

Intrigante

Answer 4

This approach did not work for me. I just added this in my code:

require 'ruby-debug'
# ... code ...
debugger

Windsor

Answer 5

Visual Studio Code has pretty good debugger, built-in. If anybody finds this searching for a way to get it to work with rake, here's a working configuration:

{
    "name": "Debug a rake task",
    "type": "Ruby",
    "request": "launch",
    "useBundler": true,
    "cwd": "${workspaceRoot}",
    "program": "/usr/local/bin/rake",
    "args": ["all"]
}

This would run the rake task all. You may have to change the path to rake, I didn't find way to run the one in PATH.

Demilune

all didn't work for me. I used rvms rake and I set args to the name of my task with a breakpoint on the first line of it and it worked for me. – Conditioned

@SomeGuyOnAComputer: Hence the sentence "This would run the rake task all". It's just the name of a task I have (/had two years ago). – Demilune

my bad I missed that – Conditioned

Answer 6

ByeBug is another one for 2.0+

https://github.com/deivid-rodriguez/byebug

Gujarati