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

Clone the repo:

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

To see the messages sent by the shell process:

Dbg.trace(:send)

Clear all trace flags for current process:

Dbg.clear()

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

Dbg.trace(self(), :call)

Then add the function to traced calls:

Dbg.call(&Map.new/0)

Call the function to see a trace message:

Map.new()

Cancel tracing for Map.new/0:

Dbg.cancel(&Map.new/0)

And clear the trace flags for self():

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 application() do
  [applications: [:dbg]]
end

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.