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merbanan / rtl_433

Program to decode radio transmissions from devices on the ISM bands (and other frequencies)
GNU General Public License v2.0
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prometheus export does not set content-type #3106

Closed Mindavi closed 21 hours ago

Mindavi commented 22 hours ago

I am running into an issue with the prometheus exporter since updating to prometheus 3.0. It appears they added some stricter checking of the Content-Type in https://github.com/prometheus/prometheus/pull/15136.

For now I'll try to set the fallback_scrape_protocol to work around this, but I think it would be good if rtl_433 advertises which protocol it supports by setting the Content-Type as Prometheus expects.

I might pick this up myself at some point, but I want to write this out already so it's documented.

rtl_433 version: 24.10 from nixpkgs.

The following error is logged by the Prometheus scraper:

Dec 02 22:25:19 aqua prometheus[791595]: time=2024-12-02T22:25:19.842+01:00 level=ERROR source=scrape.go:1585 msg="Failed to determine correct type of scrape target." component="scrape manager" scrape_pool=rtl_433 target=http://127.0.0.1:8433/metrics content_type="" fallback_media_type="" err="non-compliant scrape target sending blank Content-Type and no fallback_scrape_protocol specified for target"

Curl call to the rtl_433 endpoint:

# request the rtl_433 endpoint
$ curl -v http://127.0.0.1:8433/metrics
*   Trying 127.0.0.1:8433...
* Connected to 127.0.0.1 (127.0.0.1) port 8433
* using HTTP/1.x
> GET /metrics HTTP/1.1
> Host: 127.0.0.1:8433
> User-Agent: curl/8.11.0
> Accept: */*
> 
* Request completely sent off
< HTTP/1.1 200 OK
< Content-Length: 1277
< 
# TYPE uptime_seconds counter
# UNIT uptime_seconds seconds
# HELP uptime_seconds Program uptime.
uptime_seconds_total 87982.0
uptime_seconds_created 1733086848.0
# TYPE decoder_enabled gauge
# HELP decoder_enabled Number of enabled decoders.
decoder_enabled 230
# TYPE input_uptime_seconds counter
# UNIT input_uptime_seconds seconds
# HELP input_uptime_seconds SDR Receiver uptime.
input_uptime_seconds_total 87978.0
input_uptime_seconds_created 1733086848.0
# TYPE input_count_frames counter
# UNIT input_count_frames frames
# HELP input_count_frames Number of SDR frames received.
input_count_frames_total 167817
# TYPE input_squelch_frames counter
# UNIT input_squelch_frames frames
# HELP input_squelch_frames Number of SDR frames skipped by squelch.
input_squelch_frames_total 161825
# TYPE input_ook_frames counter
# UNIT input_ook_frames frames
# HELP input_ook_frames Number of SDR frames with OOK demodulation.
input_ook_frames_total 2677
# TYPE input_fsk_frames counter
# UNIT input_fsk_frames frames
# HELP input_fsk_frames Number of SDR frames with FSK demodulation.
input_fsk_frames_total 31
# TYPE input_event_frames counter
# UNIT input_event_frames frames
# HELP input_event_frames Number of SDR frames with decode events.
input_event_frames_total 2649
# EOF
* Connection #0 to host 127.0.0.1 left intact

Curl call to a (more) compliant endpoint:

# request a compliant endpoint (hydra_queue_runner)
$ curl -v http://127.0.0.1:9200/metrics
*   Trying 127.0.0.1:9200...
* Connected to 127.0.0.1 (127.0.0.1) port 9200
* using HTTP/1.x
> GET /metrics HTTP/1.1
> Host: 127.0.0.1:9200
> User-Agent: curl/8.11.0
> Accept: */*
> 
* Request completely sent off
< HTTP/1.1 200 OK
< Content-Type: text/plain; version=0.0.4; charset=utf-8
< Date: Mon, 02 Dec 2024 21:27:05 GMT
< Transfer-Encoding: chunked
< 
# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.
# TYPE go_gc_duration_seconds summary
go_gc_duration_seconds{quantile="0"} 2.2481e-05
go_gc_duration_seconds{quantile="0.25"} 4.3517e-05
go_gc_duration_seconds{quantile="0.5"} 7.5452e-05
go_gc_duration_seconds{quantile="0.75"} 0.000191393
go_gc_duration_seconds{quantile="1"} 0.007130977
go_gc_duration_seconds_sum 0.394173027
zuckschwerdt commented 21 hours ago

Thanks for the detailed report! I'll quickly add the header and attribute you in the commit.