Dbg

Dbg provides functions for tracing events in the BEAM VM.

Many events, including function calls and return, exception raising, sending and receiving messages, spawning, exiting, linking, scheduling and garbage collection can be traced across a cluster of nodes using Dbg.

Try it out

Or alternatively clone the repo to try it out:

git clone https://github.com/fishcakez/dbg.git
cd dbg
mix compile
iex -S mix

To see the messages sent my the shell process:

Dbg.trace(:send)

Clear all trace flags:

Dbg.clear()

To trace a call, add the :call flag to a process:

Dbg.trace(self(), :call)

Then add the function:

Dbg.call(&Map.new/0)

Call the function to see a trace:

Map.new()

Cancel tracing for Map.new/0:

Dbg.cancel(&Map.new/0)

And clear the trace flags:

Dbg.clear(self())

To reset all tracing:

Dbg.reset()

Read The Docs

Dbg allows much more sophisticated tracing. To get the docs:

mix deps.get
MIX_ENV=docs mix docs

Install As Dependency

As a dependency to a mix.es file:

def deps() do
  [{:dbg, github: "fishcakez/dbg"}]
end

Compatibility With Erlang

Dbg is a wrapper around OTP's :dbg module from the :runtime_tools application. :dbg functions will work as normal and can be combined with Dbg function calls.