Can we measure module and function usage?

Could probably use mix xref to get the data?

I don’t see anything in the standard mix xref output that looks like what I want, but it seems likely that the collected data could be massaged into an interesting report. Maybe I’ll look into that…

There is no support to count usage statisitcs for all functions, this is what you can do on your own, but there is support for counting usage of single particular functions, and this is mix xref callers.

Based on this page, I’ve done a bit of experimentation. The results are quite promising, but I’m confused about some usage details. Using IEx from the command line, I can get a List of Maps, eg:

$ cd .../apps/common
$ iex -S mix
...
iex(1)> Mix.Tasks.Xref.calls
[
  %{
    callee: {Common.Maps, :keyss, 1},
    caller_module: Common,
    file: "lib/common.ex",
    line: 46
  }, ... ]

What I’d like to do, however, is have one of my apps make this call for itself and all of the others, so that it can construct a display page, etc. I tried changing the current directory within IEx, but I still got the report for the original directory:

iex(2)> cd "../info_web"
iex(3)> Mix.Tasks.Xref.calls
[
  %{
    callee: {Common.Maps, :keyss, 1},
    caller_module: Common,
    file: "lib/common.ex",
    line: 46
  }, ... ]

So, I have two questions. First, is there a way to get the data for another app from within the same IEx session? Second (and more critically), how can I do all this from within one of my running apps? (Inquiring gnomes need to mine…)