config.go

Documentation: google.golang.org/grpc/xds/internal/balancer/ringhash

     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  	"encoding/json"
    23  	"fmt"
    24  
    25  	"google.golang.org/grpc/internal/envconfig"
    26  	"google.golang.org/grpc/serviceconfig"
    27  )
    28  
    29  // LBConfig is the balancer config for ring_hash balancer.
    30  type LBConfig struct {
    31  	serviceconfig.LoadBalancingConfig `json:"-"`
    32  
    33  	MinRingSize uint64 `json:"minRingSize,omitempty"`
    34  	MaxRingSize uint64 `json:"maxRingSize,omitempty"`
    35  }
    36  
    37  const (
    38  	defaultMinSize         = 1024
    39  	defaultMaxSize         = 4096
    40  	ringHashSizeUpperBound = 8 * 1024 * 1024 // 8M
    41  )
    42  
    43  func parseConfig(c json.RawMessage) (*LBConfig, error) {
    44  	var cfg LBConfig
    45  	if err := json.Unmarshal(c, &cfg); err != nil {
    46  		return nil, err
    47  	}
    48  	if cfg.MinRingSize > ringHashSizeUpperBound {
    49  		return nil, fmt.Errorf("min_ring_size value of %d is greater than max supported value %d for this field", cfg.MinRingSize, ringHashSizeUpperBound)
    50  	}
    51  	if cfg.MaxRingSize > ringHashSizeUpperBound {
    52  		return nil, fmt.Errorf("max_ring_size value of %d is greater than max supported value %d for this field", cfg.MaxRingSize, ringHashSizeUpperBound)
    53  	}
    54  	if cfg.MinRingSize == 0 {
    55  		cfg.MinRingSize = defaultMinSize
    56  	}
    57  	if cfg.MaxRingSize == 0 {
    58  		cfg.MaxRingSize = defaultMaxSize
    59  	}
    60  	if cfg.MinRingSize > cfg.MaxRingSize {
    61  		return nil, fmt.Errorf("min %v is greater than max %v", cfg.MinRingSize, cfg.MaxRingSize)
    62  	}
    63  	if cfg.MinRingSize > envconfig.RingHashCap {
    64  		cfg.MinRingSize = envconfig.RingHashCap
    65  	}
    66  	if cfg.MaxRingSize > envconfig.RingHashCap {
    67  		cfg.MaxRingSize = envconfig.RingHashCap
    68  	}
    69  	return &cfg, nil
    70  }
    71
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