What's wrong?

Setting the marshaler type to sumo_ic prevents Alloy from starting with the error:

Failed to build component: building component: traces are not supported by sumo_ic output format

Investigation:

This is an Alloy bug and it might not be super easy to solve: with Otel exporters, we check the telemetry types that are supported by the component and create the underlying exporters. The awss3 exporter supports all telemetry types so we create a trace exporter, a log exporter, and a metric exporter, even if only logs are connected to it. But for this particular exporter there is a catch: traces and metrics are not supported if you set the sumo_ic marshaller (see the code here).

The exporter does not know which signal types are connected to it. One solution could be for the component to have its own implementation of the Component interface instead of using the base class so that it can control which exporter to start depending on the config. (we do this for other components like the otelcol.processor.discovery)

Steps to reproduce

Run the config:

otelcol.receiver.loki "default" {
	output {
		logs    = [otelcol.exporter.awss3.default.input]
	}
}

otelcol.exporter.awss3 "default" {
  s3_uploader {
    region = "us-east-1"
    s3_bucket = "logs_bucket"
    s3_prefix = "logs"
  }
  marshaler {
    type = "sumo_ic"
  }
}

Software version

Alloy 1.7.1