edb

The next-generation debugger for Erlang.

Prerequisites

edb currently requires a modified version of Erlang/OTP which, for convenience, is checked in as a git submodule, until all require changes will make it upstream.

You can build and install the modified version of Erlang/OTP by doing:

$ git submodule update --init
$ pushd otp
$ ./configure --prefix $(pwd)/../otp-bin
$ make -j$(nproc)
$ make -j$(nproc) install
$ popd

Note: on Mac you may need to provide a custom installation path for OpenSSl. Just replace the above configuration step with:

$ ./configure --prefix $(pwd)/../otp-bin --with-ssl=$(brew --prefix openssl)

Then simply add the installation dir to your $PATH:

$ export PATH=$(pwd)/otp-bin/bin:$PATH

Verify the Erlang installation:

$ which erl # Should point to the newly built version of Erlang/OTP

You will also need a version of rebar3 built with Erlang/OTP 26 or higher. You can find instructions on how to build rebar3 from source here.

Get EDB

You can either download a pre-built version of the EDB debugger or build it from source.

Download

You can visit the Releases page for EDB and download a pre-built version of EDB.

You can also download an EDB version for a specific commit by visiting the Commits History page, click on the "green tick" next to a given commit, click on "details" for the CI job, check the "Summary". You will find the pre-built versions among the "artifacts" for the commit.

Build from source

A pre-built version of EDB for your OS/architecture may not be available. In that case you can build one from source. Remember to check the Prerequisites sections for details.

$ git clone https://github.com/WhatsApp/edb.git
$ cd edb
$ rebar3 escriptize

The produced edb escript will be available in:

_build/default/bin/edb

Usage

Start the DAP adapter for edb

$ _build/default/bin/edb dap

This is the command that you tipically want your IDE (VS Code, Emacs) to trigger.

Configure a rebar3 project

Before we can debug a rebar3 project with EDB, we need to ensure that we build the code using the beam_debug_info option.

Since we want to only use the debugger to debug test and we don't want to affect production, these changes can be limited to the test profile.

Open the rebar.config file for the project and ensure the beam_debug_info option is included as part of erl_opts.

{profiles, [
    {test, [
        {erl_opts, [debug_info, beam_debug_info]}
    ]}
]}.

Troubleshooting

DAP Logs

When started EDB as a DAP debugger, EDB logs useful information that can help you understanding whether EDB is communicating correctly with a client (tipically, the IDE).

To find the location of the EDB DAP logs on your machine, open an Erlang shell and run:

$ erl

Erlang/OTP [...]

Eshell [...] (press Ctrl+G to abort, type help(). for help)
1> filename:basedir(user_log, "edb").

That will return the path where you will find a edb.log file.

License

EDB is Apache 2.0 licensed, as found in the LICENSE.md file.