@launchdarkly/js-server-sdk-common/dist/api/data/LDMigrationVariation.d.ts

LaunchDarkly Server SDK for JavaScript - common code

import { LDMigrationOrigin } from '../LDMigration';
import { LDMigrationOp, LDMigrationOpEvent } from './LDMigrationOpEvent';
import { LDMigrationStage } from './LDMigrationStage';
/**
 * Used for reporting the state of a consistency check.
 */
export declare enum LDConsistencyCheck {
    Inconsistent = 0,
    Consistent = 1,
    NotChecked = 2
}
/**
 * Used to track information related to a migration operation.
 */
export interface LDMigrationTracker {
    /**
     * Sets the migration related operation associated with these tracking measurements.
     *
     * @param op The operation being tracked.
     */
    op(op: LDMigrationOp): void;
    /**
     * Report that an error has occurred for the specified origin.
     *
     * @param origin The origin of the error.
     */
    error(origin: LDMigrationOrigin): void;
    /**
     * Check the consistency of a read result. This method should be invoked if the `check` function
     * is defined for the migration and both reads ("new"/"old") were done.
     *
     * The function will use the checkRatio to determine if the check should be executed, and it
     * will record the result.
     *
     * Example calling the check function from the migration config.
     * ```
     * context.tracker.consistency(() => config.check!(oldValue.result, newValue.result));
     * ```
     *
     * If the consistency check function throws an exception, then the consistency check result
     * will not be included in the generated event.
     *
     * @param check The function which executes the check. This is not the `check` function from the
     * migration options, but instead should be a parameter-less function that calls that function.
     */
    consistency(check: () => boolean): void;
    /**
     * Call this to report that an origin was invoked (executed). There are some situations where the
     * expectation is that both the old and new implementation will be used, but with writes
     * it is possible that the non-authoritative will not execute. Reporting the execution allows
     * for more accurate analytics.
     *
     * @param origin The origin that was invoked.
     */
    invoked(origin: LDMigrationOrigin): void;
    /**
     * Report the latency of an operation.
     *
     * @param origin The origin the latency is being reported for.
     * @param value The latency, in milliseconds, of the operation.
     */
    latency(origin: LDMigrationOrigin, value: number): void;
    /**
     * Create a migration op event. If the event could not be created, because of a missing
     * operation, then undefined is returned.
     */
    createEvent(): LDMigrationOpEvent | undefined;
}
/**
 * Migration value and tracker.
 */
export interface LDMigrationVariation {
    /**
     * The result of the flag evaluation. This will be either one of the flag's variations or
     * the default value that was passed to `LDClient.migrationVariation`.
     */
    value: LDMigrationStage;
    /**
     * A tracker which can be used to generate analytics for the migration.
     */
    tracker: LDMigrationTracker;
}
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