/
fixtures.go
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/
fixtures.go
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// Copyright (c) 2016-2019 Uber Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package hrw
import (
"crypto/rand"
"encoding/hex"
"strconv"
)
// NodeKeysTable is a Node to keys map utility type
type NodeKeysTable map[string]map[string]struct{}
// All functions defined in this file are intended for testing purposes only.
// RendezvousHashFixture creates a weigthed rendezvous hashing object with
// specified #numKey of keys, a hash function (we use sha256.New primarely for testing) and
// the list of weights which define nodes in rendezvous hashing schema and assign weights to
// them in their natural order. The nodes will be also initialized with seed names equal
// to their corresponding indices in the array, so for
// RendezvousHashFixture(10, sha256.New, 100, 200, 300) there will be a RendezvousHash object created
// with 3 nodes "0": 100, "1":200, "2":300
// The fixture will return RendezvousHash object and the node key buckets table
func RendezvousHashFixture(numKeys int, hashFactory HashFactory, scoreFunc UIntToFloat, weights ...int) (*RendezvousHash, map[string]map[string]struct{}) {
rh := NewRendezvousHash(hashFactory, scoreFunc)
keys := NodeKeysTable{}
b := make([]byte, 64)
totalWeights := 0
for index, weight := range weights {
totalWeights += weight
rh.AddNode(strconv.Itoa(index), weight)
keys[strconv.Itoa(index)] = make(map[string]struct{})
}
// 1500 the sum of all weights
for i := 0; i < numKeys; i++ {
rand.Read(b)
key := hex.EncodeToString(b)
nodes := rh.GetOrderedNodes(key, 1)
keys[nodes[0].Label][key] = struct{}{}
}
return rh, keys
}
//HashKeyFixture generate #numkeys random keys according to a hash function
func HashKeyFixture(numKeys int, hashFactory HashFactory) []string {
var keys []string
b := make([]byte, 64)
for i := 0; i < numKeys; i++ {
rand.Read(b)
key := hex.EncodeToString(b)
keys = append(keys, key)
}
return keys
}