[WIP] dns: add support for clusters based on SRV DNS record

[mikhainin]

One more attempt to address #125 (resolve cluster IPs via SRV-record)

Yet on early stage. Tested with Consul and the collowing configuration:

  clusters:
  - name: local-php
    connect_timeout: 0.25s
    lb_policy: round_robin
    # http2_protocol_options: {}
    cluster_type:
      name: envoy.clusters.dns_srv
      typed_config:
        "@type": "type.googleapis.com/envoy.extensions.clusters.dns_srv.v3.Cluster"
        srv_names:
          - srv_name: _local-php._tcp.service.consul.
    dns_resolvers:
    typed_dns_resolver_config:
      name: envoy.network.dns_resolver.cares
      typed_config:
        "@type": type.googleapis.com/envoy.extensions.network.dns_resolver.cares.v3.CaresDnsResolverConfig
        resolvers:
          - socket_address:
              address: 127.0.0.1
              port_value: 8600

Based on discussion and design doc by @kylebevans in #125 (comment)

[repokitteh-read-only]

As a reminder, PRs marked as draft will not be automatically assigned reviewers,
or be handled by maintainer-oncall triage.

Please mark your PR as ready when you want it to be reviewed!

🐱

Caused by: #35160 was opened by mikhainin.

see: more, trace.

[repokitteh-read-only]

CC @envoyproxy/api-shepherds: Your approval is needed for changes made to (api/envoy/|docs/root/api-docs/).
envoyproxy/api-shepherds assignee is @wbpcode
CC @envoyproxy/api-watchers: FYI only for changes made to (api/envoy/|docs/root/api-docs/).

🐱

Caused by: #35160 was opened by mikhainin.

see: more, trace.

[mikhainin]

Testing locally with Consul:
run consul:

consul agent -server -advertise=127.0.0.1 -data-dir=consul-data -ui -bootstrap-expect=1 -dev -log-level=debug

Add service nodes:

consul services register -name=local-php -id=web-1 -address=192.168.1.102 -port=80 -tag=v1 -tag=prod
consul services register -name=local-php -id=web-2 -address=192.168.1.102 -port=81 -tag=v1 -tag=prod

Verify that the service local-php can be resolved via Consul:

dig @127.0.0.1 -p 8600 local-php.service.consul. SRV
# or
dig @127.0.0.1 -p 8600 _local-php._tcp.service.consul. SRV

main doc: https://developer.hashicorp.com/consul/docs/services/discovery/dns-static-lookups

[mikhainin]

Hi there, apologies for openning in this state - I acknowledge that there still lots.
I just needed someone to point me at what I'm missing and get feedback whether I'm going in the right direction.

[wbpcode]

Thanks for you contribution. But based on our contributing rules (see https://github.com/envoyproxy/envoy/blob/main/CONTRIBUTING.md), any extension, should have a maintainer sponsor to help review and maintain the code.

And I think this should be a DNS extension rather than a new cluster extension?

[mikhainin]

should have a maintainer sponsor to help review and maintain the code

@wbpcode, Thank you for your comment. I posted a message in slack some while ago but didn't hear anything back. What would be the right way for this?

And I think this should be a DNS extension rather than a new cluster extension?

Based on previous discussion, it was decided to go with the cluster extension. Basically, I followed the previous proposal.

I will be happy to discuss the new design if someone helps me to find the right place. The initial issue doesn't seem to have activity :/

[github-actions]

This pull request has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in 7 days if no further activity occurs. Please feel free to give a status update now, ping for review, or re-open when it's ready. Thank you for your contributions!

[mikhainin]

This isn't yet forgotten, going to ping maintainers in the maillist