Could not fetch metrics from squid instance unexpected EOF

[sarakumap]

Describe the bug
getting following error with squid version 5.7 with require-proxy-header set.
squid_exporter is failing to read squid metrics and return the following error:

systemctl status squid_exporter

Aug 01 14:50:03 xxxx.xx.xx.local squid-exporter[3883]: 2023/08/01 14:50:03 Could not fetch metrics from squid instance: unexpected EOF

when I looks at the squid log I see the following error. May be this one is causing this error.

error:transaction-end-before-headers NONE/0.0" 0 0 NONE_NONE:HIER_NONE

logs

curl localhost:19101 where squid exporter is listening. it is missing the squid metrics

HELP promhttp_metric_handler_requests_total Total number of scrapes by HTTP status code.

TYPE promhttp_metric_handler_requests_total counter

promhttp_metric_handler_requests_total{code="200"} 13214
promhttp_metric_handler_requests_total{code="500"} 0
promhttp_metric_handler_requests_total{code="503"} 0

HELP squid_exporter_build_info A metric with a constant '1' value labeled by version, revision, branch, and goversion from which squid_exporter was built.

TYPE squid_exporter_build_info gauge

squid_exporter_build_info{branch="HEAD",goversion="go1.13.8",revision="c60ca5a56e34783af00b8d7f959bc18d0d6aefa6",version="1.8.3"} 1

HELP squid_up Was the last query of squid successful?

TYPE squid_up gauge

squid_up{host="localhost"} 0

To Reproduce
Steps to reproduce the behavior:
make a request to destination via squid pproxy using loadbalancer
check the squid exporter log and notice the error:

Expected behavior
A clear and concise description of what you expected to happen.

OS (please complete the following information):

• OS: Centos
• Version 7

Additional context
Add any other context about the problem here.

[sarakumap]

error from squid logs:
Aug 03 00:32:33 xxx.xx.xx.local squid[26823]: PROXY protocol error: invalid header from local=127.0.0.1:14101 remote=127.0.0.1:44302 FD 12 flags=1

[sarakumap]

I got it fixed by adding a separate port for http for exposing metrics for squid_exporter.
http_port 14101 require-proxy-header
http_port 24101

[MaciekLeks]

Hello @sarakumap, could you share more config parts cause I'm facing the same error.

[boynux]

thanks @sarakumap, I really appreciate if you add a sentence or two in FAQ section of the README.md file explaining how to fix this issue. That would hopefully address @MaciekLeks question as well.

[boynux]

@MaciekLeks something like the config snippet below should technically work if you have the same issue:

Note: make sure to update ports and IP address of squid-exporter to your requirements

http_port 3128 require-proxy-header
http_port 3129

acl managerAdmin src <exporter IP address>
acl managerPort port 3129
http_access allow localhost managerPort manager
http_access allow managerAdmin managerPort manager
http_access deny manager