dr-cabal

dr-cabal is a CLI tool for profiling Haskell dependencies build times.

ℹ️ DISCLAIMER: This project is developed and maintained in free time by volunteers. The development may continue for decades or may stop tomorrow. You can use GitHub Sponsorship to support the development of this project.

Install

dr-cabal is a Haskell CLI tool and can be installed either from Hackage or from this repository.

Prerequisites

To start using dr-cabal, make sure you have the required version of cabal-install (a Haskell build tool) and GHC (a Haskell compiler) installed:

• Cabal ⩾ 3.6.2.0
• GHC ⩾ 9.0.2

Hackage

To install the latest version of dr-cabal from Hackage, follow these steps:

1. Update Hackage index:

   cabal update
   

2. Build dr-cabal from Hackage and copy the resulting executable into the desired location:

   cabal install dr-cabal \
       --install-method=copy \
       --overwrite-policy=always \
       --with-compiler=ghc-9.0.2
       --installdir=$HOME/.local/bin
   

ℹ️ NOTE: Make sure the $HOME/.local/bin directory or the directory of your choice is listed in $PATH.

Sources

To build the latest version of dr-cabal from sources, follow these steps:

1. Clone this repository:

   git clone https://github.com/chshersh/dr-cabal.git
   cd dr-cabal
   

2. Build the package:

   cabal build
   

3. Copy executable to the desired location:

   cp $(cabal list-bin exe:dr-cabal) ~/.local/bin/dr-cabal
   

ℹ️ NOTE: Make sure the ~/.local/bin directory or the directory of your choice is listed in $PATH.

How to use?

dr-cabal usages comprises two steps:

1. 👀 Watching cabal build output and recording data into a JSON file.
2. 🌈 Producing pretty profiling results.

Watch

⚠️ WARNING: To get meaningful results, the dr-cabal watch command needs to be run when none of the dependencies are build. If you've already build you project, including dependencies, you can purge global Cabal cache using the following command:

rm -rf ~/.cabal

You may prefer a less invasive approach if you have custom global Cabal configurations:

rm -rf ~/.cabal/store

However, with the latter solution you won't see the Downloading phase in the profiling output.

Run the following command inside the project directory, for which you want to build the profile chart:

cabal build all | dr-cabal watch --output=dr-cabal-debug.json

This command watches the cabal build output and records all the relevant steps in the dr-cabal-debug.json file.

If everything is good, you should see output similar to the below one:

Profile

Once you successfully produced a JSON file with all the recorded steps, run the following command to pretty-print the profiling output:

⚠️ WARNING: For better results, make your terminal full-screen.

cabal profile --input=dr-cabal-debug.json

You'll see the output like on the image below: