1 | ;
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2 | /*
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3 | * Copyright 2019 gRPC authors.
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4 | *
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5 | * Licensed under the Apache License, Version 2.0 (the "License");
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6 | * you may not use this file except in compliance with the License.
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7 | * You may obtain a copy of the License at
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8 | *
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9 | * http://www.apache.org/licenses/LICENSE-2.0
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10 | *
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11 | * Unless required by applicable law or agreed to in writing, software
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12 | * distributed under the License is distributed on an "AS IS" BASIS,
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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14 | * See the License for the specific language governing permissions and
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15 | * limitations under the License.
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16 | *
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17 | */
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18 | Object.defineProperty(exports, "__esModule", { value: true });
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19 | exports.BackoffTimeout = void 0;
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20 | const INITIAL_BACKOFF_MS = 1000;
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21 | const BACKOFF_MULTIPLIER = 1.6;
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22 | const MAX_BACKOFF_MS = 120000;
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23 | const BACKOFF_JITTER = 0.2;
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24 | /**
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25 | * Get a number uniformly at random in the range [min, max)
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26 | * @param min
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27 | * @param max
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28 | */
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29 | function uniformRandom(min, max) {
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30 | return Math.random() * (max - min) + min;
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31 | }
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32 | class BackoffTimeout {
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33 | constructor(callback, options) {
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34 | this.callback = callback;
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35 | /**
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36 | * The delay time at the start, and after each reset.
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37 | */
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38 | this.initialDelay = INITIAL_BACKOFF_MS;
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39 | /**
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40 | * The exponential backoff multiplier.
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41 | */
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42 | this.multiplier = BACKOFF_MULTIPLIER;
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43 | /**
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44 | * The maximum delay time
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45 | */
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46 | this.maxDelay = MAX_BACKOFF_MS;
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47 | /**
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48 | * The maximum fraction by which the delay time can randomly vary after
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49 | * applying the multiplier.
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50 | */
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51 | this.jitter = BACKOFF_JITTER;
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52 | /**
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53 | * Indicates whether the timer is currently running.
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54 | */
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55 | this.running = false;
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56 | /**
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57 | * Indicates whether the timer should keep the Node process running if no
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58 | * other async operation is doing so.
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59 | */
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60 | this.hasRef = true;
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61 | /**
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62 | * The time that the currently running timer was started. Only valid if
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63 | * running is true.
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64 | */
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65 | this.startTime = new Date();
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66 | if (options) {
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67 | if (options.initialDelay) {
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68 | this.initialDelay = options.initialDelay;
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69 | }
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70 | if (options.multiplier) {
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71 | this.multiplier = options.multiplier;
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72 | }
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73 | if (options.jitter) {
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74 | this.jitter = options.jitter;
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75 | }
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76 | if (options.maxDelay) {
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77 | this.maxDelay = options.maxDelay;
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78 | }
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79 | }
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80 | this.nextDelay = this.initialDelay;
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81 | this.timerId = setTimeout(() => { }, 0);
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82 | clearTimeout(this.timerId);
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83 | }
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84 | runTimer(delay) {
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85 | var _a, _b;
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86 | clearTimeout(this.timerId);
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87 | this.timerId = setTimeout(() => {
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88 | this.callback();
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89 | this.running = false;
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90 | }, delay);
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91 | if (!this.hasRef) {
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92 | (_b = (_a = this.timerId).unref) === null || _b === void 0 ? void 0 : _b.call(_a);
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93 | }
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94 | }
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95 | /**
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96 | * Call the callback after the current amount of delay time
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97 | */
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98 | runOnce() {
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99 | this.running = true;
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100 | this.startTime = new Date();
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101 | this.runTimer(this.nextDelay);
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102 | const nextBackoff = Math.min(this.nextDelay * this.multiplier, this.maxDelay);
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103 | const jitterMagnitude = nextBackoff * this.jitter;
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104 | this.nextDelay =
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105 | nextBackoff + uniformRandom(-jitterMagnitude, jitterMagnitude);
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106 | }
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107 | /**
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108 | * Stop the timer. The callback will not be called until `runOnce` is called
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109 | * again.
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110 | */
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111 | stop() {
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112 | clearTimeout(this.timerId);
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113 | this.running = false;
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114 | }
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115 | /**
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116 | * Reset the delay time to its initial value. If the timer is still running,
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117 | * retroactively apply that reset to the current timer.
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118 | */
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119 | reset() {
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120 | this.nextDelay = this.initialDelay;
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121 | if (this.running) {
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122 | const now = new Date();
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123 | const newEndTime = this.startTime;
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124 | newEndTime.setMilliseconds(newEndTime.getMilliseconds() + this.nextDelay);
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125 | clearTimeout(this.timerId);
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126 | if (now < newEndTime) {
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127 | this.runTimer(newEndTime.getTime() - now.getTime());
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128 | }
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129 | else {
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130 | this.running = false;
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131 | }
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132 | }
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133 | }
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134 | /**
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135 | * Check whether the timer is currently running.
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136 | */
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137 | isRunning() {
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138 | return this.running;
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139 | }
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140 | /**
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141 | * Set that while the timer is running, it should keep the Node process
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142 | * running.
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143 | */
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144 | ref() {
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145 | var _a, _b;
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146 | this.hasRef = true;
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147 | (_b = (_a = this.timerId).ref) === null || _b === void 0 ? void 0 : _b.call(_a);
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148 | }
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149 | /**
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150 | * Set that while the timer is running, it should not keep the Node process
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151 | * running.
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152 | */
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153 | unref() {
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154 | var _a, _b;
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155 | this.hasRef = false;
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156 | (_b = (_a = this.timerId).unref) === null || _b === void 0 ? void 0 : _b.call(_a);
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157 | }
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158 | }
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159 | exports.BackoffTimeout = BackoffTimeout;
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160 | //# sourceMappingURL=backoff-timeout.js.map |
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