Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 | 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x | // Circuit breaker pattern for spawn failure protection
import { createLogger } from './logger.js';
const logBreaker = createLogger('circuit:breaker');
/**
* Circuit breaker states
*/
const BreakerState = {
CLOSED: 'closed', // Normal operation
OPEN: 'open', // Failing, rejecting requests
HALF_OPEN: 'half_open', // Testing if recovery is possible
};
/**
* Circuit breaker for protecting against repeated failures
*/
export class CircuitBreaker {
/**
* @param {object} options
* @param {string} options.name - Breaker name for logging
* @param {number} options.failureThreshold - Number of failures before opening (default: 5)
* @param {number} options.resetTimeMs - Time before attempting recovery (default: 30000)
* @param {number} options.halfOpenMaxAttempts - Max attempts in half-open state (default: 1)
*/
constructor({ name = 'default', failureThreshold = 5, resetTimeMs = 30000, halfOpenMaxAttempts = 1 } = {}) {
this.name = name;
this.failureThreshold = failureThreshold;
this.resetTimeMs = resetTimeMs;
this.halfOpenMaxAttempts = halfOpenMaxAttempts;
this.state = BreakerState.CLOSED;
this.failureCount = 0;
this.lastFailureTime = null;
this.halfOpenAttempts = 0;
}
/**
* Check if the circuit breaker allows the operation
* @returns {boolean} - True if operation is allowed
*/
isAllowed() {
if (this.state === BreakerState.CLOSED) {
return true;
}
if (this.state === BreakerState.OPEN) {
// Check if enough time has passed to try again
const now = Date.now();
if (now - this.lastFailureTime >= this.resetTimeMs) {
this.state = BreakerState.HALF_OPEN;
this.halfOpenAttempts = 0;
logBreaker.info('Circuit breaker transitioning to half-open', { name: this.name });
return true;
}
return false;
}
// HALF_OPEN state
if (this.halfOpenAttempts < this.halfOpenMaxAttempts) {
return true;
}
return false;
}
/**
* Record a successful operation
*/
recordSuccess() {
if (this.state === BreakerState.HALF_OPEN) {
// Recovery successful - close the circuit
this.state = BreakerState.CLOSED;
this.failureCount = 0;
this.halfOpenAttempts = 0;
logBreaker.info('Circuit breaker closed after successful recovery', { name: this.name });
} else if (this.state === BreakerState.CLOSED && this.failureCount > 0) {
// Reset failure count on success
this.failureCount = 0;
}
}
/**
* Record a failed operation
*/
recordFailure() {
this.lastFailureTime = Date.now();
if (this.state === BreakerState.HALF_OPEN) {
this.halfOpenAttempts++;
if (this.halfOpenAttempts >= this.halfOpenMaxAttempts) {
// Recovery failed - reopen the circuit
this.state = BreakerState.OPEN;
logBreaker.warn('Circuit breaker reopened after failed recovery', { name: this.name });
}
return;
}
this.failureCount++;
logBreaker.debug('Failure recorded', {
name: this.name,
failureCount: this.failureCount,
threshold: this.failureThreshold,
});
if (this.failureCount >= this.failureThreshold) {
this.state = BreakerState.OPEN;
logBreaker.warn('Circuit breaker opened', {
name: this.name,
failureCount: this.failureCount,
resetTimeMs: this.resetTimeMs,
});
}
}
/**
* Get current circuit breaker status
* @returns {object} - Status info
*/
getStatus() {
return {
name: this.name,
state: this.state,
failureCount: this.failureCount,
lastFailureTime: this.lastFailureTime,
isAllowed: this.isAllowed(),
};
}
/**
* Reset the circuit breaker to closed state
*/
reset() {
this.state = BreakerState.CLOSED;
this.failureCount = 0;
this.lastFailureTime = null;
this.halfOpenAttempts = 0;
logBreaker.info('Circuit breaker reset', { name: this.name });
}
}
export { BreakerState };
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