[Hearbeat] Nil panic inside ELB provider

[emilioalvap]

• Version: 8.8.
• Operating System: any
• Discuss Forum URL: https://discuss.elastic.co/t/heartbeat-auto-discover-not-working-for-aws-elb/337187

Summary

ELB provider is trying to derefrence a nil pointer at one point, causing panic:

github.com/elastic/beats/v7/x-pack/libbeat/autodiscover/providers/aws/elb.(*fetchRequest).fetchListeners(0xc000322b00, {{0xc000cda7e0, 0x4, 0x4}, 0xc001069590, 0xc000b89548, 0x0, 0xc001069560, {0xc00005ab84, 0x4}, ...})
github.com/elastic/beats/v7/x-pack/libbeat/autodiscover/providers/aws/elb/fetch.go:204

This is the derefence: https://github.com/elastic/beats/blob/f7fa407aff97e3218d5fa2a89cc940a1c00f8608/x-pack/libbeat/autodiscover/providers/aws/elb/fetch.go#L204

[elasticmachine]

Pinging @elastic/uptime (Team:Uptime)

[paulb-elastic]

Linking to https://github.com/elastic/beats/issues/29782

[botelastic[bot]]

Hi! We just realized that we haven't looked into this issue in a while. We're sorry!

We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!

[emilioalvap]

Closing this one since AWS ELB autodiscovery has been deprecated by https://github.com/elastic/beats/issues/29782 for a while and will be removed in a future release.