Adds automation for generating the map of `gRPC Method Name → Rate Limit Type`
used by the middleware introduced in #15550, and will ensure we don't forget
to add new endpoints.
Engineers must annotate their RPCs in the proto file like so:
```
rpc Foo(FooRequest) returns (FooResponse) {
option (consul.internal.ratelimit.spec) = {
operation_type: READ,
};
}
```
When they run `make proto` a protoc plugin `protoc-gen-consul-rate-limit` will
be installed that writes rate-limit specs as a JSON array to a file called
`.ratelimit.tmp` (one per protobuf package/directory).
After running Buf, `make proto` will execute a post-process script that will
ingest all of the `.ratelimit.tmp` files and generate a Go file containing the
mappings in the `agent/grpc-middleware` package. In the enterprise repository,
it will write an additional file with the enterprise-only endpoints.
If an engineer forgets to add the annotation to a new RPC, the plugin will
return an error like so:
```
RPC Foo is missing rate-limit specification, fix it with:
import "proto-public/annotations/ratelimit/ratelimit.proto";
service Bar {
rpc Foo(...) returns (...) {
option (hashicorp.consul.internal.ratelimit.spec) = {
operation_type: OPERATION_READ | OPERATION_WRITE | OPERATION_EXEMPT,
};
}
}
```
In the future, this annotation can be extended to support rate-limit
category (e.g. KV vs Catalog) and to determine the retry policy.
This mimics xDS's discovery protocol where you must request a resource
explicitly for the exporting side to send those events to you.
As part of this I aligned the overall ResourceURL with the TypeURL that
gets embedded into the encoded protobuf Any construct. The
CheckServiceNodes is now wrapped in a better named "ExportedService"
struct now.
We cannot do this for "subscribe" and "partition" this easily without
breakage so those are omitted.
Any protobuf message passed around via an Any construct will have the
fully qualified package name embedded in the protobuf as a string. Also
RPC method dispatch will include the package of the service during
serialization.
- We will be passing pbservice and pbpeering through an Any as part of
peer stream replication.
- We will be exposing two new gRPC services via pbpeering and
pbpeerstream.
- Use some protobuf construction helper methods for brevity.
- Rename a local variable to avoid later shadowing.
- Rename the Nonce field to be more like xDS's naming.
- Be more explicit about which PeerID fields are empty.
Peer replication is intended to be between separate Consul installs and
effectively should be considered "external". This PR moves the peer
stream replication bidirectional RPC endpoint to the external gRPC
server and ensures that things continue to function.
Dan Upton