open-consul/agent/grpc-internal/services/subscribe/subscribe.go
Dan Upton 34140ff3e0
grpc: rename public/private directories to external/internal (#13721)
Previously, public referred to gRPC services that are both exposed on
the dedicated gRPC port and have their definitions in the proto-public
directory (so were considered usable by 3rd parties). Whereas private
referred to services on the multiplexed server port that are only usable
by agents and other servers.

Now, we're splitting these definitions, such that external/internal
refers to the port and public/private refers to whether they can be used
by 3rd parties.

This is necessary because the peering replication API needs to be
exposed on the dedicated port, but is not (yet) suitable for use by 3rd
parties.
2022-07-13 16:33:48 +01:00

121 lines
3.1 KiB
Go

package subscribe
import (
"errors"
"github.com/hashicorp/go-hclog"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
"github.com/hashicorp/consul/acl"
"github.com/hashicorp/consul/agent/consul/state"
"github.com/hashicorp/consul/agent/consul/stream"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/proto/pbsubscribe"
)
// Server implements a StateChangeSubscriptionServer for accepting SubscribeRequests,
// and sending events to the subscription topic.
type Server struct {
Backend Backend
Logger Logger
}
func NewServer(backend Backend, logger Logger) *Server {
return &Server{Backend: backend, Logger: logger}
}
type Logger interface {
Trace(msg string, args ...interface{})
With(args ...interface{}) hclog.Logger
}
var _ pbsubscribe.StateChangeSubscriptionServer = (*Server)(nil)
type Backend interface {
ResolveTokenAndDefaultMeta(token string, entMeta *acl.EnterpriseMeta, authzContext *acl.AuthorizerContext) (acl.Authorizer, error)
Forward(info structs.RPCInfo, f func(*grpc.ClientConn) error) (handled bool, err error)
Subscribe(req *stream.SubscribeRequest) (*stream.Subscription, error)
}
func (h *Server) Subscribe(req *pbsubscribe.SubscribeRequest, serverStream pbsubscribe.StateChangeSubscription_SubscribeServer) error {
logger := newLoggerForRequest(h.Logger, req)
handled, err := h.Backend.Forward(req, forwardToDC(req, serverStream, logger))
if handled || err != nil {
return err
}
logger.Trace("new subscription")
defer logger.Trace("subscription closed")
entMeta := req.EnterpriseMeta()
authz, err := h.Backend.ResolveTokenAndDefaultMeta(req.Token, &entMeta, nil)
if err != nil {
return err
}
subReq, err := state.PBToStreamSubscribeRequest(req, entMeta)
if err != nil {
return status.Error(codes.InvalidArgument, err.Error())
}
sub, err := h.Backend.Subscribe(subReq)
if err != nil {
return err
}
defer sub.Unsubscribe()
ctx := serverStream.Context()
elog := &eventLogger{logger: logger}
for {
event, err := sub.Next(ctx)
switch {
case errors.Is(err, stream.ErrSubForceClosed):
logger.Trace("subscription reset by server")
return status.Error(codes.Aborted, err.Error())
case err != nil:
return err
}
if !event.Payload.HasReadPermission(authz) {
continue
}
elog.Trace(event)
// TODO: This conversion could be cached if needed
e := event.Payload.ToSubscriptionEvent(event.Index)
if err := serverStream.Send(e); err != nil {
return err
}
}
}
func forwardToDC(
req *pbsubscribe.SubscribeRequest,
serverStream pbsubscribe.StateChangeSubscription_SubscribeServer,
logger Logger,
) func(conn *grpc.ClientConn) error {
return func(conn *grpc.ClientConn) error {
logger.Trace("forwarding to another DC")
defer logger.Trace("forwarded stream closed")
client := pbsubscribe.NewStateChangeSubscriptionClient(conn)
streamHandle, err := client.Subscribe(serverStream.Context(), req)
if err != nil {
return err
}
for {
event, err := streamHandle.Recv()
if err != nil {
return err
}
if err := serverStream.Send(event); err != nil {
return err
}
}
}
}