:telemetry integration for nebula_graph_ex.

Events

All events share the same measurement and metadata shapes.

[:nebula_graph_ex, :query, :start]

Emitted immediately before a query is sent to NebulaGraph.

Measurements: %{system_time: integer()}

Metadata: %{statement: binary(), params: map(), opts: keyword()}

[:nebula_graph_ex, :query, :stop]

Emitted after a successful query response is received and decoded.

Measurements: %{duration: integer()} — native time units (use :erlang.convert_time_unit/3 to convert to milliseconds).

Metadata: %{statement: binary(), params: map(), result: %NebulaGraphEx.ResultSet{}, opts: keyword()}

[:nebula_graph_ex, :query, :exception]

Emitted when a query raises or returns {:error, _}.

Measurements: %{duration: integer()}

Metadata: %{statement: binary(), params: map(), error: %NebulaGraphEx.Error{}, opts: keyword()}

Attaching a default handler

Call NebulaGraphEx.Telemetry.attach_default_handler/0 to log all queries at the :debug level:

NebulaGraphEx.Telemetry.attach_default_handler()

This is meant for development. In production, attach your own handler that sends metrics to your observability backend.

Custom handler example

:telemetry.attach(
  "my-app-nebula-handler",
  [:nebula_graph_ex, :query, :stop],
  fn _event, %{duration: dur}, %{statement: stmt}, _config ->
    ms = System.convert_time_unit(dur, :native, :millisecond)
    MyApp.Metrics.histogram("nebula.query.duration_ms", ms, tags: [stmt: stmt])
  end,
  nil
)