go.temporal.io/server@v1.23.0/common/backoff/jitter.go (about)

     1  // The MIT License
     2  //
     3  // Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
     4  //
     5  // Copyright (c) 2020 Uber Technologies, Inc.
     6  //
     7  // Permission is hereby granted, free of charge, to any person obtaining a copy
     8  // of this software and associated documentation files (the "Software"), to deal
     9  // in the Software without restriction, including without limitation the rights
    10  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    11  // copies of the Software, and to permit persons to whom the Software is
    12  // furnished to do so, subject to the following conditions:
    13  //
    14  // The above copyright notice and this permission notice shall be included in
    15  // all copies or substantial portions of the Software.
    16  //
    17  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    18  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    19  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    20  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    21  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    22  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    23  // THE SOFTWARE.
    24  
    25  package backoff
    26  
    27  import (
    28  	"math/rand"
    29  )
    30  
    31  const fullCoefficient float64 = 1
    32  
    33  // FullJitter return random number from 0 to input, inclusive, exclusive
    34  func FullJitter[T ~int64 | ~int | ~int32 | ~float64 | ~float32](input T) T {
    35  	return Jitter(input, fullCoefficient) / 2
    36  }
    37  
    38  // Jitter return random number from (1-coefficient)*input to (1+coefficient)*input, inclusive, exclusive
    39  func Jitter[T ~int64 | ~int | ~int32 | ~float64 | ~float32](input T, coefficient float64) T {
    40  	validateCoefficient(coefficient)
    41  
    42  	if coefficient == 0 {
    43  		return input
    44  	}
    45  
    46  	base := float64(input) * (1 - coefficient)
    47  	addon := rand.Float64() * 2 * (float64(input) - base)
    48  	return T(base + addon)
    49  }
    50  
    51  func validateCoefficient(coefficient float64) {
    52  	if coefficient < 0 || coefficient > 1 {
    53  		panic("coefficient cannot be < 0 or > 1")
    54  	}
    55  }