go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/server/limiter/grpc.go (about)

     1  // Copyright 2020 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package limiter
    16  
    17  import (
    18  	"context"
    19  
    20  	"google.golang.org/grpc/codes"
    21  	"google.golang.org/grpc/status"
    22  
    23  	"go.chromium.org/luci/grpc/grpcutil"
    24  )
    25  
    26  // NewServerInterceptor returns a UnifiedServerInterceptor that uses the given
    27  // limiter to accept or drop gRPC requests.
    28  func NewServerInterceptor(l *Limiter) grpcutil.UnifiedServerInterceptor {
    29  	return func(ctx context.Context, fullMethod string, handler func(context.Context) error) error {
    30  		done, err := l.CheckRequest(ctx, &RequestInfo{
    31  			CallLabel: fullMethod,
    32  			PeerLabel: PeerLabelFromAuthState(ctx),
    33  		})
    34  		if err != nil {
    35  			return status.Error(codes.Unavailable, err.Error())
    36  		}
    37  		defer done()
    38  		return handler(ctx)
    39  	}
    40  }