Not able to use recon_trace about elixir_agent HOT 3 CLOSED

Yes, we leverage the built in Erlang tracer, of which there can only be one at a time.

You might be able to turn it off with a call to erlang.trace http://erlang.org/doc/man/erlang.html#trace-3

:erlang.trace(:all, false, [])

Another approach would be to get the data you need via the agent (ie: you could put a function tracer on that function)

Is there something about the recon_trace you need in particular?

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iex([email protected])5> :erlang.trace(:all, false, [])
0

I tried it, the error still happens

Another approach would be to get the data you need via the agent (ie: you could put a function tracer on that function)
Is there something about the recon_trace you need in particular?

There are two kinds of instrumentation. One is proactive, we make a guess on what would be useful and add logs/metrics/traces earlier. We could definitely use new_relic trace for these cases.

The second kind is reactive, where we try to figure out what's going on and most of the time, we won't have enough time to add logs/traces and re-deploy the code. We use recon extensively in these cases. So far we have solved memory leaks, tcp connection leaks, ets table growth and been able to find the root cause of message queue overload etc. To give a specific example, we enabled newrelic transaction on a long-running worker process which might make 1000s of http requests. This caused high memory usage. We tracked it back by looking at the size of ets tables controlled by newrelic.

we use recon_trace as an on the fly logger, so we can quickly see what's passed between functions. It also has a rate limiter which prevents from capturing too much data and crashing the node.

Given that we can have only one tracer, Ideal solution for us would be the ability to disable features that depends on tracer before starting the debugging session and reenable it back when we finish the debugging session.

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If anyone is finding this issue by googling "can only have one tracer per process" while using the New Relic agent, updating my config to:

config :new_relic_agent,
  ...
  disable_erlang_trace: true
   

is how I was able to disable Erlang tracing.

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