How to add a replication hook to Riak v2.0+ - database-replication

Question

Background
Riak v2.0 changed the configuration system from:
vm.args (set of erlang parameters for the Riak node)
app.config (configuration of various attributes for the Riak node)
to:
riak.conf (replacing the majority of what was in vm.args and app.conf with a single configuration file [using named settings])
advanced.config (a small specific set of settings [mostly related to riak_repl])
Question
In Multi-Data-Center-Replication-Hooks the Riak v2.0+ documentation still refers to:
Add a -pa argument to your vm.args file to specify the path where your
compiled .beam file lives:
Shell
-pa /path/to/replication/hook Finally, add a -run argument to your vm.args file to register the hook:
Shell
-run riak_repl_hook_sample register
What are the riak.conf or advanced.config versions of the -pa & -run parameters?
Note: I know that in the doc:Upgrading Your Configuration System we can:
Keep your configuration files from the older system, which are still
recognized in Riak 2.0.
but we would like to move to the new configuration system as it gives us more visibility.

Answer 1

in your advanced.config file, try someting like that:
[
{riak_kv, [
{add_paths, ["/path/to/replication/hook"]}
]},
{vm_args, [
{'-run riak_repl_hook_sample register', ""}
]}
].
I know that starting an app works, I'm using this:
[
{riak_kv, [
{add_paths, ["/path/to/my/beams/"]}
]},
{vm_args, [
{'-s my_app', ""}
]}
].
So with a little fiddling you should be able to make it work :)

Answer 2

Possible solution
Note: If you want to understand how riak.conf settings are mapped to vm.args the below file is very useful, however be warned that if you do not use the below settings you will end up with blank entries in the generated vm.args file:
/var/lib/riak/generated.configs/vm..args
-pa
-run
Riak v2.0+ schema file for config
Turns out that there is a nice schema file in the riak lib directory that can be expanded to add on any missing erlang flags, for me this was:
/usr/lib64/riak/lib/10-riak.schema
To this I added:
%% Add the replication hook directory to the code path
{mapping, "repl.hook.path", "vm_args.-pa", [
{default, ""}
]}.
%% Call Module:start/0
{mapping, "repl.hook.run", "vm_args.-run", [
{default, ""}
]}.
Then I added to the riak.conf file:
# add the repl hook path and register it
repl.hook.path = /path/to/replication/hook
repl.hook.run = riak_repl_hook_sample register
after this I needed to restart the node.