While working on https://github.com/letsencrypt/boulder/pull/7238, I dug
into why the consul services config has, for example, `[ca-a, ca-b]` in
addition to `[ca1, ca2]`. Boulder test configs use `ca.service.consul`
which will return both CAs (`[ca-a, ca-b]`). For `[ca1, ca2]` though, a
grpc load balancing [integration
test](a55bf19ea0/test/integration-test.py (L121-L143))
individually targets services such as to verify that each backend is
working correctly.
- Fork the default `dns` resolver from `go-grpc` to add backend discovery via
DNS SRV resource records.
- Add new fields for SRV based discovery to `cmd.GRPCClientConfig`
- Add new (optional) field `DNSAuthority` for specifying custom DNS server to
`cmd.GRPCClientConfig`
- Add a utility method to `cmd.GRPCClientConfig` to simplify target URI and host
construction. With three schemes and `DNSAuthority` it makes more sense to
handle all of this parsing and construction outside of the RPC client
constructor.
Resolves#6111
- Add a dedicated Consul container
- Replace `sd-test-srv` with Consul
- Add documentation for configuring Consul
- Re-issue all gRPC credentials for `<service-name>.service.consul`
Part of #6111
Phil Porada