PagerDuty Integration Does Not Respect HTTP_PROXY Environment Variables

[programmerq]

Expected behavior:

PagerDuty integration should successfully communicate with the PagerDuty API using the configured HTTP proxy settings (HTTP_PROXY and HTTPS_PROXY environment variables) when making outbound network requests.

Current behavior:

PagerDuty integration attempts to reach the PagerDuty API directly, ignoring the configured HTTP proxy settings. This results in a network timeout due to the integration not utilizing the HTTP proxy for egress traffic, causing failures in establishing communication.

Bug details:

Teleport version: v15.x, but v16.4.2 also appears to be affected.

Recreation steps:

1. Configure a Teleport cluster with PagerDuty integration in an environment that utilizes an HTTP proxy for outbound traffic.
2. Set HTTP_PROXY and HTTPS_PROXY environment variables for the Teleport process.
3. Set up integration with PagerDuty the Teleport UI.
4. Observe network timeout errors indicating a failure to pass the traffic through the HTTP proxy.

Debug logs:

2024-10-15T13:04:59Z ERRO [PAGERDUTY] Plugin instance delegate failed. error:[
   ERROR REPORT:
   Original Error: *url.Error Get "https://api.pagerduty.com/abilities": context deadline exceeded
   Stack Trace:
   github.com/gravitational/teleport/integrations/access/pagerduty/client.go:156 github.com/gravitational/teleport/integrations/access/pagerduty.Pagerduty.HealthCheck
   github.com/gravitational/teleport/integrations/access/pagerduty/app.go:172 github.com/gravitational/teleport/integrations/access/pagerduty.(*App).init
   github.com/gravitational/teleport/integrations/access/pagerduty/app.go:109 github.com/gravitational/teleport/integrations/access/pagerduty.(*App).run
   github.com/gravitational/teleport/integrations/lib/process.go:234 github.com/gravitational/teleport/e/lib/plugins.pagerDutyInstanceFactory.NewApp.NewServiceJob.func2
   github.com/gravitational/teleport/integrations/lib/process.go:255 github.com/gravitational/teleport/integrations/lib.(*serviceJob).DoJob
   github.com/gravitational/teleport/integrations/lib/process.go:101 github.com/gravitational/teleport/integrations/lib.NewProcess.func2.1
   runtime/asm_amd64.s:1695 runtime.goexit
   User Message: api health check failed. check your credentials and service_id settings
   Get "https://api.pagerduty.com/abilities": context deadline exceeded] plugin_name:pagerduty plugin_type:pagerduty plugins/manager.go:361 

PagerDuty integration appears to instantiate an http Transport for use with go-resty. I think that it will need to use http.ProxyFromEnvironment on that instance in order for environment proxy settings to work.