ansible: add splunk_otel_collector_no_proxy variable

[tchernomax]

IFAIK when you need to monitor an https vhost on localhost on a proxied environment you need to add the vhost on the NO_PROXY environment variable (event if localhost is used).

    smartagent/http_toto:
      type: http
      host: 127.0.0.1
      port: 443
      useHTTPS: true
      noRedirects: true
      sniServerName: www.toto.com
      httpHeaders:
        Host: www.toto.com
      path: /up.php
      desiredCode: 200
      regex: '^OK$'

will not worked on a proxied environment if NO_PROXY=localhost,127.0.0.1,::1 ; for it to work we need NO_PROXY=localhost,127.0.0.1,::1,www.toto.com
So we need a way to set NO_PROXY.

[rmfitzpatrick]

Thanks for the update. The current template logic may be problematic for determining when to use this on setting NO_PROXY alone:

splunk-otel-collector/deployments/ansible/roles/collector/tasks/linux_install.yml

Line 29 in 4768a9c

when: splunk_otel_collector_proxy_http != "" or splunk_otel_collector_proxy_https != ""

. You could add a non-default value check but that would lead to empty values for the proxy env vars.

[tchernomax]

@rmfitzpatrick

The current template logic may be problematic for determining when to use this on setting NO_PROXY alone …

There is no point setting splunk_otel_collector_no_proxy without setting splunk_otel_collector_proxy_http(s) (no_proxy is basically an "exclude" on http(s)_proxy , so if http(s)_proxy aren't used/set there is no point setting no_proxy). So I don't think we should change the when:.

[rmfitzpatrick]

There is no point setting splunk_otel_collector_no_proxy without setting splunk_otel_collector_proxy_http(s)

It's a bit of an edge case but I think proxy env vars set via DefaultEnvironment or through another mechanism would be overwritten for the agent service.

edit: The way you've documented the var addresses this concern, so makes sense to use as is.**