OpentelemetryFunction

This package provides functions to help propagating OpenTelemetry context across functions that are executed asynchronously.

Installation

The package can be installed by adding opentelemetry_function to your list of dependencies in mix.exs:

def deps do
  [
    {:opentelemetry_function, "~> 0.1.0-rc.1"}
  ]
end

Examples

Lets say you are executing a function in a different process. For example:

task = Task.async(func)
Task.await(task, timeout)

OpenTelemetry by default does not propagate context through processes, so you'll have to do something like this:

span_ctx = OpenTelemetry.Tracer.start_span("Some expensive calculation")
ctx = OpenTelemetry.Ctx.get_current()
task = Task.async(fn ->
  OpenTelemetry.Ctx.attach(ctx)
  OpenTelemetry.Tracer.set_current_span(span_ctx)

  func.()
end)
Task.await(task, timeout)
OpenTelemetry.Span.end_span(span_ctx)

With this module you can use wrap/2 function instead:

task = Task.async(OpentelemetryFunction.wrap(func, "Some expensive calculation"))
Task.await(task, timeout)

This helps to keep the code short and to the point.

If you do not provide the span name, then Function.wrap is used as the span name.

OpenTelemetry.Tracer functions that work on the current span can be used as well:

OpenTelemetry.Tracer.update_name("Some expensive calculation")

Documentation

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/opentelemetry_function.