wrong syntax on docs

[prem-prakash]

the syntax bellow does not work

defmodule Searcher do
  use ScoutApm.Tracing

  # Time associated with this function will appear under "Hound" in timeseries charts.
  # The function will appear as `Hound/open_search` in transaction traces.
  @timing(category: "Hound")
  def open_search(url) do
    navigate_to(url)
  end

  # Time associated with this function will appear under "Hound" in timeseries charts.
  # The function will appear as `Hound/search` in transaction traces.
  @timing(category: "Hound", name: "search")
  def open_search(url) do
    navigate_to(url)
  end

tried on a module:

defmodule Apollo.Cache.MemcachedAdapter do
  @moduledoc """
  Wrapper around Memcache to allow timing instrumentation
  """
  use ScoutApm.Tracing

  alias Apollo.MemcachedWorker

  @timing category: "Memcached", name: "get"
  def get(key) do
    Memcache.get(MemcachedWorker, key)
  end

  @timing category: "Memcached", name: "set"
  def set(key, value) do
    Memcache.set(MemcachedWorker, key, value)
  end

  @timing category: "Memcached", name: "delete"
  def delete(key) do
    Memcache.delete(MemcachedWorker, key)
  end

  @timing category: "Memcached", name: "incr"
  def incr(key) do
    Memcache.incr(MemcachedWorker, key, default: 1, by: 1)
  end
end

the erlang VM starts to consume memory and the module became unresponsive

changing for this syntax it works fine

defmodule Apollo.Cache.MemcachedAdapter do
  @moduledoc """
  Wrapper around Memcache to allow timing instrumentation
  """
  import ScoutApm.Tracing

  alias Apollo.MemcachedWorker

  def get(key) do
    timing("Memcached", "get") do
      Memcache.get(MemcachedWorker, key)
    end
  end

  def set(key, value) do
    timing("Memcached", "set") do
      Memcache.set(MemcachedWorker, key, value)
    end
  end

  def delete(key) do
    timing("Memcached", "delete") do
      Memcache.delete(MemcachedWorker, key)
    end
  end

  def incr(key) do
    timing("Memcached", "incr") do
      Memcache.incr(MemcachedWorker, key, default: 1, by: 1)
    end
  end
end

[cschneid]

Thank you for the report. We've recently reworked some parts of custom instrumentation to play nicer. The function annotations were clever, but caused some issues, and the next release will provide a midpoint option for instrumentation. I'm glad you have the inside-the-function version of tracing working.

To clarify, the code compiled ok, but failed at runtime?

[prem-prakash]

yes the code compiled ok but failed at runtime by becoming unresponsive, or by changing the response of the functions, putting them inside a list with "do" as first item [do:, response]

[cschneid]

FYI - we're deprecating the @transaction and @timing approach to instrumentation, starting with the freshly released 0.4.1 version of the agent.

Now, prefer using a new macro called deftiming:

@timing_opts [category: "Memcached", name: "incr"]
deftiming incr(key) do
  # ...
end

[itsderek23]

@cschneid - we need to update the help docs, correct?

http://help.apm.scoutapp.com/#timing-functions-and-blocks-of-code

[jstr]

It looks like both the docs linked above and those on Hex.pm (e.g. the code comments) are out of date with regard to the deprecations.

[cschneid]

@jstr - I just looked at our generated docs and it looks ok. We do still document the @transaction style, which we should further deemphasise, but the newer style deftransaction is there as the recommended version.

Can you point to what you're seeing?

[mitchellhenke]

The docs have been updated to reflect the deprecation of @timing in favor of the new implementation and style. If it is unclear, please let us know! 🙂