Prometheus exporter does not support openmetrics-text 1.0.0

[jonatan-ivanov]

Component(s)

exporter/prometheus

What happened?

Description

It seems the Prometheus exporter does not support openmetrics-text 1.0.0, it only supports openmetrics-text 0.0.1.

Steps to Reproduce

Scrape the /metrics endpoint and request openmetrics-text 1.0.0:

Accept: application/openmetrics-text; version=1.0.0; charset=utf-8

Expected Result

Result in OpenMetrics format, also the content-type should be:

Content-Type: application/openmetrics-text; version=1.0.0; charset=utf-8

Actual Result

Result in Prometheus plaintext format, the content-type says the same:

Content-Type: text/plain; version=0.0.4; charset=utf-8

Collector version

otel/opentelemetry-collector-contrib:cdf47846a7ff

Environment information

Environment

OS: MacOS 13.2.1

OpenTelemetry Collector configuration

receivers:
  otlp:
    protocols:
      grpc:
      http:

exporters:
  prometheus:
    endpoint: '0.0.0.0:9090'
    metric_expiration: 1m
    enable_open_metrics: true
    resource_to_telemetry_conversion:
      enabled: true

service:
  pipelines:
    metrics:
      receivers: [otlp]
      exporters: [prometheus]

Log output

No response

Additional context

If I scrape the /metrics endpoint and request openmetrics-text 0.0.1, I get the response in the OpenMetrics format:

Accept: application/openmetrics-text; version=0.0.1; charset=utf-8

will result in

Content-Type: application/openmetrics-text; version=0.0.1; charset=utf-8

The problem is that 0.0.1 should not be used, only 1.0.0.
According to the OpenMetrics specs:

The content type MUST be: application/openmetrics-text; version=1.0.0; charset=utf-8

Also the Prometheus server uses 1.0.0 for scraping: prometheus/prometheus#9430

[github-actions]

Pinging code owners:

• exporter/prometheus: @Aneurysm9

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[Aneurysm9]

The prometheus exporter uses promhttp to handle requests. The content type negotiation for OpenMetrics exposition is handled by that package and gets the OpenMetrics version from another Prometheus-owned package. If this is fixed upstream we will inherit the fix.

[jonatan-ivanov]

Thanks, do you think it would worth adding tests for this on OTel side?

[jonatan-ivanov]

fyi: prometheus/common#456

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• exporter/prometheus: @Aneurysm9

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[jonatan-ivanov]

@Aneurysm9 Do you know anyone we can ping on Prometheus side about this?
Also, Is there anything that can be done on OTel side?

[Aneurysm9]

@gouthamve do you know if there is any movement on the Prometheus end for this? What impact will folding OpenMetrics into Prometheus have on this?

[jonatan-ivanov]

Fyi, it seems the fix for the issue in Prometheus was released.

[gouthamve]

opened: prometheus/prometheus#12411

[gouthamve]

Hi @jonatan-ivanov, this should be fixed now. Can we close this?

[jonatan-ivanov]

Thanks! I checked 0.80.0, I checked it with Micrometer's integration tests, it seems it support application/openmetrics-text; version=1.0.0. Though 0.80.0 contains a bunch of breaking changes so I'm not going to migrate Micrometer tests to 0.0.80 just yet.

From my/Micrometer's perspective, I think this issue can be closed.
From Otel perspective, do you think it would worth adding tests for this?

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• exporter/prometheus: @Aneurysm9

See Adding Labels via Comments if you do not have permissions to add labels yourself.