ejabberd and Erlang installation with lager_transform undefined

Question

I am new to Erlang, I have been trying to install Erlang and ejabberd on EC2 ubuntu machine, everything went well till I started compiling some external modules in ejabberd. It started throwing error undefined parse transform 'lager_transform'.

I tried everything which is as below:

1. Did rebar get-deps, make clean, make deps, make install. After this I am able to see that lager_transform.beam is made and present in /lib/ folder.
2. Checked rebar.config file, it had lager deps on top, which is widely suggested, no help even after that.
3. Added -compile[{parse_tranform},{lager_transform}] on top of module, even then their is no luck.

I am really blocked on this, and not able to complete the installation. I have done this before on fedora with ejabberd 15.11 and otp 18.2, at that time it was using p1_logger instead of lager. But now when I am installing fresh with otp 18.2 and ejabberd 16.0 or 15.11, I am getting lager_transform undefined error.

Answer 1

Navigate to your ejabberd project directory cd /path/to/ejabberd

Fetch dependencies rebar get-deps

Compile the project with verbose output rebar compile -v

If issues persist, perform a clean build make clean make deps make

Verify that the lager_transform.beam is in the expected directory find _build/default/lib/lager/ebin -name "lager_transform.beam"

Set Erlang library path export ERL_LIBS=/path/to/ejabberd/_build/default/lib

Compile again to see if the issue is resolved rebar compile -v

Answer 2

Please make sure you compile ejabberd as described in documentation: http://docs.ejabberd.im/admin/guide/installation/#installing-ejabberd-from-source-code

For example, you can compile it with:

./configure --enable-lager --enable-mysql
make

You need to run configure and make to set properly the build chain.