Allow to configure EctoLogger through :telemetry

For complex umbrella apps, having a global config for the :spandex_ecto
library can be limiting - particularly when a different tracer is to be
used depending on the repo.

This change allows to pass configuration to the underlying EctoLogger
module, like the `:tracer` option, through the `config` argument in
`:telemetry.attach/4`.

lib/spandex_ecto/ecto_logger.ex

@@ -11,9 +11,13 @@ defmodule SpandexEcto.EctoLogger do
 
   @empty_query_placeholder "unknown (unsupported ecto adapter?)"
 
-  def trace(log_entry, database) do
+  def trace(log_entry, database, config \\ []) do
     # Put in your own configuration here
-    config = Application.get_env(:spandex_ecto, __MODULE__)
+    config =
+      :spandex_ecto
+      |> Application.get_env(__MODULE__)
+      |> Keyword.merge(config || [])
+
     tracer = config[:tracer] || raise "tracer is a required option for #{inspect(__MODULE__)}"
     service = config[:service] || :ecto
     truncate = config[:truncate] || 5000

lib/spandex_ecto/telemetry_adapter.ex

@@ -6,12 +6,12 @@ defmodule SpandexEcto.TelemetryAdapter do
   alias SpandexEcto.EctoLogger
 
   #  this is for ecto_sql 3.0.x
-  def handle_event([_app_name, repo_name, :query], total_time, log_entry, _config) when is_integer(total_time) do
-    EctoLogger.trace(log_entry, "#{repo_name}_database")
+  def handle_event([_app_name, repo_name, :query], total_time, log_entry, config) when is_integer(total_time) do
+    EctoLogger.trace(log_entry, "#{repo_name}_database", config)
   end
 
   # This is for ecto_sql >= 3.1
-  def handle_event([_app_name, repo_name, :query], measurements, metadata, _config) when is_map(measurements) do
+  def handle_event([_app_name, repo_name, :query], measurements, metadata, config) when is_map(measurements) do
     log_entry = %{
       query: metadata.query,
       source: metadata.source,
@@ -22,7 +22,7 @@ defmodule SpandexEcto.TelemetryAdapter do
       result: wrap_result(metadata.result)
     }
 
-    EctoLogger.trace(log_entry, "#{repo_name}_database")
+    EctoLogger.trace(log_entry, "#{repo_name}_database", config)
   end
 
   def handle_event(event_name, measurements, log_entry, config) when is_list(event_name) do