signalfxexporter: Prometheus Summary Type Not Implemented

[alanbrent]

Describe the bug

The Prometheus Metric Summary type is not implemented in the signalfxexporter.

See converter.go for proof of the missing type.

Steps to reproduce

1. Setup otelcol-contrib to receive Prometheus metrics that you know contain summary metrics and export them to the signalfxexporter
2. Notice that all summary metric types are missing.

What did you expect to see?

I expected to see the summary metrics appear in SignalFx along with the other metrics.

What did you see instead?

The summary metrics did not appear. Non-summary metrics did appear.

What version did you use?

v0.23.0

What config did you use?

Standard YAML config file, similar to the below (our airflow reports statsd metrics to a Prometheus statsd-exporter container)

receivers:
  prometheus/airflow:
    config:
      scrape_configs:
        - job_name: "prom-airflow"
          scrape_interval: 10s
          kubernetes_sd_configs:
            - role: service
          relabel_configs:
            - source_labels: [__meta_kubernetes_service_port_name]
              regex: prometheus-scrape-endpoint
              action: keep
            - source_labels: [__address__]
              action: replace
              target_label: instance
              regex: (.+)
              replacement: $1:9102
exporters:
  signalfx/airflow:
    access_token: ${SFX_ACCESS_TOKEN_AIRFLOW}
    realm: us0
processors:
  batch:
  memory_limiter:
    ballast_size_mib: ${OTELCOL_MEMORY_LIMITER_BALLAST_SIZE_MIB}
    limit_mib: ${OTELCOL_MEMORY_LIMITER_LIMIT_MIB}
    spike_limit_mib: ${OTELCOL_MEMORY_LIMITER_SPIKE_LIMIT_MIB}
    check_interval: ${OTELCOL_MEMORY_LIMITER_CHECK_INTERVAL_SECONDS}s
  k8s_tagger:
pipelines:
    metrics/airflow:
      receivers: [prometheus/airflow]
      processors: [memory_limiter, batch, k8s_tagger]
      exporters: [signalfx/airflow]

Environment

We use the official otelcolcontrib container image with some lightweight tooling added in.

Additional context

1. Thanks to @jrcamp for the Slack discussion here
2. Originally I thought the issue was with the prometheusreceiver, but I narrowed it down to the signalfxexporter by using the file exporter and confirming that the metrics are actually picked up by the receiver.

[alanbrent]

Closing after confirming functionality in the v0.24.0 release, which contains the changes in #2998.

Thanks for the fix, we were able to clear out some tech debt today because of it!