Checking for correct Behaviour in module_info/0 in API

[ioolkos]

Exploring things a little bit, I noticed that I can't set tracers when the .beam files are stripped in a prod release, I think.
There reason is the check for the correct Behaviour here:

opentelemetry-erlang/apps/opentelemetry_api/src/opentelemetry.erl

Line 376 in 618ccd4

case lists:keyfind(behaviour, 1, Attributes) of

The module_info/0 call might look like this, giving an empty attributes list:

1> otel_tracer_default:module_info().
[{module,otel_tracer_default},
 {exports,[{start_span,3},
           {start_span,4},
           {with_span,3},
           {with_span,4},
           {b3_propagators,0},
           {w3c_propagators,0},
           {module_info,0},
           {module_info,1}]},
 {attributes,[]},
 {compile,[]},
 {native,false},
 {md5,<<229,142,94,192,207,250,193,205,25,119,87,154,29,
        226,111,166>>}]
2> 

Do you think this is a correct assessment, and is it a case that matters?

[tsloughter]

Argh, yes, we should remove this check.

[ioolkos]

Ok, something like this then:

-spec set_default_tracer(tracer()) -> boolean().
set_default_tracer(Tracer) ->
    persistent_term:put({?MODULE, default_tracer}, Tracer).

-spec set_tracer(atom(), tracer()) -> boolean().
set_tracer(Name, Tracer) ->
    persistent_term:put({?MODULE, Name}, Tracer).

-spec set_default_meter(meter()) -> boolean().
set_default_meter(Meter) ->
    persistent_term:put({?MODULE, default_meter}, Meter).

-spec set_meter(atom(), meter()) -> boolean().
set_meter(Name, Meter) ->
    persistent_term:put({?MODULE, Name}, Meter).

[tsloughter]

It can still check if the module exists, even if it doesn't depend on the tracer behaviour being there.

[tsloughter]

I added a fix here #137

[ioolkos]

Thanks! I'll test it.

[ioolkos]

Behaves as expected now. Thanks.