prysm-pulse/validator/client/multiple_endpoints_grpc_resolver.go

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package client
import (
"strings"
"google.golang.org/grpc/resolver"
)
// Modification of a default grpc passthrough resolver (google.golang.org/grpc/resolver/passthrough) allowing to use multiple addresses
// in grpc endpoint. Example:
// conn, err := grpc.DialContext(ctx, "127.0.0.1:4000,127.0.0.1:4001", grpc.WithInsecure(), grpc.WithResolvers(&multipleEndpointsGrpcResolverBuilder{}))
// It can be used with any grpc load balancer (pick_first, round_robin). Default is pick_first.
// Round robin can be used by adding the following option:
// grpc.WithDefaultServiceConfig("{\"loadBalancingConfig\":[{\"round_robin\":{}}]}")
type multipleEndpointsGrpcResolverBuilder struct{}
func (*multipleEndpointsGrpcResolverBuilder) Build(target resolver.Target, cc resolver.ClientConn, _ resolver.BuildOptions) (resolver.Resolver, error) {
r := &multipleEndpointsGrpcResolver{
target: target,
cc: cc,
}
r.start()
return r, nil
}
func (*multipleEndpointsGrpcResolverBuilder) Scheme() string {
return resolver.GetDefaultScheme()
}
type multipleEndpointsGrpcResolver struct {
target resolver.Target
cc resolver.ClientConn
}
func (r *multipleEndpointsGrpcResolver) start() {
endpoints := strings.Split(r.target.Endpoint, ",")
var addrs []resolver.Address
for _, endpoint := range endpoints {
addrs = append(addrs, resolver.Address{Addr: endpoint})
}
r.cc.UpdateState(resolver.State{Addresses: addrs})
}
func (*multipleEndpointsGrpcResolver) ResolveNow(_ resolver.ResolveNowOptions) {}
func (*multipleEndpointsGrpcResolver) Close() {}