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?

Answer 1

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.

Answer 2

I found the solution.

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

or on some systems

$ rdebug rake my:task

Answer 3

I highly recommend pry for this

bundle install pry
require 'pry'
rake ...

In your rake task file:

binding.pry 

Answer 4

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

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

Answer 5

ByeBug is another one for 2.0+

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

Answer 6

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.