task-sharding/dist/types.d.ts

Shards tasks in a cluster using consistent hashing

/**
 * Configuration for the TaskSharding class.
 * @typedef {object} TaskShardingConfig
 * @property {number} [delay] The usual delay in milliseconds until the tasks are rebalanced across the nodes when the list of node changes.
 * @property {number} [maxDelay] The maximal delay in milliseconds until the tasks are rebalanced across the nodes when the list of node changes.
 * @property {Array<string>} [nodes] Initial list of node names that participate in the task sharding. This list should contain the 'selfNode' if present.
 * @property {string} [selfNode] The name of this node.
 */
declare type TaskShardingConfig = {
    delay: number;
    maxDelay: number;
    nodes: string[];
    selfNode: string;
};

/**
 * Shard tasks between nodes in a cluster, using consistent hashing.
 * @export
 * @class
 * @extends EventEmitter
 */
declare class TaskSharding {
    constructor(conf?: TaskShardingConfig);

    /**
     * Sets/replaces the list of nodes that participate in the task sharding.
     * @param {string|Array<string>|object} nodes The new replacement node(s). String for one server. Array for multiple servers. Object for mapping between server names and vnode weight number.
     * @memberof TaskSharding
     */
    setNodes(nodes: string | string[] | any): void;

    /**
     * Adds one or more nodes to the list of nodes that participate in the task sharding.
     * @param {string|Array<string>|object} node The new node(s) that should be added. String for one server. Array for multiple servers. Object for mapping between server names and vnode weight number.
     * @memberof TaskSharding
     */
    addNode(node: string | string[] | any): void;

    /**
     * Removes one or more nodes from the list of nodes that participate in the task sharding.
     * @param {string|Array<string>|object} node The current node(s) that should be removed. String for one server. Array for multiple servers. Object for mapping between server names and vnode weight number.
     * @memberof TaskSharding
     */
    removeNode(node: string | string[] | any): void;

    /**
     * The (self) name of this node/instance. Undefined if not set so far.
     * @member {string}
     * @readonly
     * @memberof TaskSharding
     * @return {string}
     */
    readonly selfNode: string;

    /**
     * Removes a task by its id.
     * @param {string} id The task id that should be removed.
     * @return {boolean} true if the task was removed (since it was present); else false.
     * @memberof TaskSharding
     */
    removeTask(id: string): boolean;

    /**
     * Adds a task by its id.
     * @param {string} id The task id that should be added.
     * @return {string} The owner node name.
     * @memberof TaskSharding
     */
    addTask(id: string): string;

    /**
     * Checks if this node is the owner for the given task (tasks not previously added will return false as well).
     * @param {string} id The task id that should be checked.
     * @return {boolean} true if and only if the selfNode is the owner for the given task; else false.
     * @memberof TaskSharding
     */
    isOwned(id: string): boolean;

    /**
     * Gets the owner node name for the task with the given id (task ids not previously added will return undefined).
     * @param {string} id The task id of which the owner should be retrieved.
     * @return {string} The owner node name of the task. 'undefined' if no such task was added previously.
     * @memberof TaskSharding
     */
    getOwner(id: string): string;

    /**
     * Event name when a task gets revoked to this node.
     * @function on
     * @instance
     * @param {string} eventName The name of the event.
     * @param {function} listener The callback function
     * @memberof TaskSharding
     */
    on(eventName: string, listener: any): void;

    /**
     * Event name when a task gets assigned to this node.
     * @member {string}
     * @static
     * @memberof TaskSharding
     */
    static TASK_ASSIGNED_EVENT: string;

    /**
     * Event name when a task gets revoked to this node.
     * @member {string}
     * @static
     * @memberof TaskSharding
     */
    static TASK_REVOKED_EVENT: string;

}