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Interfaces & Types

This page documents the interfaces and type aliases exported by Zenvark.

Interfaces​

BreakerStrategy​

Interface for implementing custom breaker strategies.

interface BreakerStrategy {
  shouldOpenCircuit(events: CallResultEvent[]): boolean;
}

See Breaker Strategies for implementation examples.

BackoffStrategy​

Interface for implementing custom backoff strategies.

interface BackoffStrategy {
  getDelayMs(attempt: number): number;
}

See Backoff Strategies for implementation examples.

BreakerMetricsRecorder​

Interface for implementing custom metrics collection.

interface BreakerMetricsRecorder {
  initialize?(breakerId: string): void;
  recordCall(params: RecordCallParams): void;
  recordBlockedRequest(params: RecordBlockedRequestParams): void;
  recordHealthCheck(params: RecordHealthCheckParams): void;
}

See Metrics & Observability for implementation examples.

Type Aliases​

CallResultEvent​

Represents a call execution event with timing and outcome information.

type CallResultEvent = {
  id: string; // Unique identifier for this call event (Redis stream ID)
  callResult: CallResult; // The outcome of the call (SUCCESS or FAILURE)
  timestamp: number; // Unix timestamp in milliseconds when the call occurred
};

Used in breaker strategies to evaluate call history and determine if the circuit should open.

RecordCallParams​

Parameters for recording a call execution.

type RecordCallParams = {
  breakerId: string;
  result: CallResult;
  durationMs: number;
};

Used by BreakerMetricsRecorder.recordCall() to record successful or failed calls.

RecordBlockedRequestParams​

Parameters for recording a blocked request.

type RecordBlockedRequestParams = {
  breakerId: string;
};

Used by BreakerMetricsRecorder.recordBlockedRequest() when requests are blocked due to an open circuit.

RecordHealthCheckParams​

Parameters for recording a health check execution.

type RecordHealthCheckParams = {
  breakerId: string;
  type: HealthCheckType;
  result: CallResult;
  durationMs: number;
};

Used by BreakerMetricsRecorder.recordHealthCheck() to record health check attempts.