google.golang.org/grpc@v1.72.2/xds/internal/balancer/ringhash/util.go (about)

     1  /*
     2   *
     3   * Copyright 2021 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  package ringhash
    20  
    21  import (
    22  	"context"
    23  )
    24  
    25  type xdsHashKey struct{}
    26  
    27  // XDSRequestHash returns the request hash in the context and true if it was set
    28  // from the xDS config selector. If the xDS config selector has not set the hash,
    29  // it returns 0 and false.
    30  func XDSRequestHash(ctx context.Context) (uint64, bool) {
    31  	requestHash := ctx.Value(xdsHashKey{})
    32  	if requestHash == nil {
    33  		return 0, false
    34  	}
    35  	return requestHash.(uint64), true
    36  }
    37  
    38  // SetXDSRequestHash adds the request hash to the context for use in Ring Hash
    39  // Load Balancing using xDS route hash_policy.
    40  func SetXDSRequestHash(ctx context.Context, requestHash uint64) context.Context {
    41  	return context.WithValue(ctx, xdsHashKey{}, requestHash)
    42  }