rails_dt

Ruby/Rails debug toolkit

rails_dt gem gives you the DT.p() method to print debug messages.

Usage

In your Gemfile, add:

gem "rails_dt", "git: https://github.com/dadooda/rails_dt.git"

Now, in your code, do something like:

DT.p "checkpoint 1"
DT.p "user", user

Debug messages are printed to:

• Rails.logger in Rails mode (auto-detected);
• STDERR in non-Rails mode;
• log/dt.log if log/ exists in project root and is writable.

This is often handy:

$ tail -f log/dt.log

The ideas behind it

• Debug message printer must not require initialization.
• Debug message printer must be nothing else, but a debug message printer.
• Debug message printer must be invoked the same way regardless of place of invocation.
• Debug message printer calls must be clearly visible in code.
• Debug message printer must print its location in code so you can easily remove the call once debugging is over.

A few out-of-the-box implementations review

Let me check a few popular out-of-the box implementation used by many of developers against "the ideas" items listed above.

Rails.logger:

• Fail. It only works in Rails. Rails requires initialization.
• (!) Fail. Logger is a production facility.
• So-so. It's not possible to use Rails logger to debug parts of Rails itself.
• (!) Fail. Debugging logger calls look the same as production logger calls.
• Fail. Location in code is not printed.

Kernel::p:

• OK.
• OK.
• OK.
• So-so. p calls hide well among lines of meaningful code and it isn't always easy to spot them.
• Fail. Location in code is not printed.

Cheers!

Feedback of any kind is greatly appreciated.

— Alex Fortuna, © 2010-2017