options.ts

// BSD 3-Clause License
//
// Copyright (c) 2018, IBM Corporation
// All rights reserved.
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import { UnimplementedError } from "../errors";
import {
    BasicRedisClusterOptions,
    BasicRedisOptions,
    BasicRedisSentinelOptions,
    BasicRedisSocketOptions,
    BasicRedisTcpOptions,
} from "./basic_options";

import * as IoRedis from "ioredis";

/**
 * `RedisOptions` objects encapsulate the logic of Redis client creation.
 *
 * @see createOptions
 */
export interface RedisOptions {
    /**
     * @param override Options to be written over existing options before
     *                 creating the client
     * @returns A Redis client configured according to the class type.
     */
    createClient(override?: object): IoRedis.Redis;

    /**
     * @returns A URI that lossily encodes a `RedisOptions` object.
     */
    createUri(): string;
}

/**
 * @param options The options to copy from.
 * @returns A new options object with old options copied from `options` and
 *          certain options forced to a value.
 */
const appendDefaultOptions = <T extends BasicRedisOptions>(options: T): T => {
    const appended = {
        ...options as object,
        dropBufferSupport: true,
        keyPrefix: "celery-task-meta-",
        stringNumbers: true,
    };

    return appended as T;
};

/**
 */
const maybeOverride = <T extends BasicRedisOptions>(
    options: T,
    override?: object
): T => {
    if (typeof override === "undefined") {
        return options;
    }

    // tslint:disable:no-object-literal-type-assertion
    return { ...options as object, ...override } as T;
};

/**
 * `RedisTcpOptions` creates Redis clients that connect to a single database
 * over TCP.
 */
export class RedisTcpOptions implements RedisOptions {
    public readonly options: BasicRedisTcpOptions;

    public constructor(options: BasicRedisTcpOptions) {
        this.options = appendDefaultOptions(options);
    }

    public createClient(override?: object): IoRedis.Redis {
        return new IoRedis(maybeOverride(this.options, override));
    }

    public createUri(): string {
        let uri = "redis";

        if (typeof this.options.tls !== "undefined") {
            uri += "s";
        }

        uri += "://";

        if (typeof this.options.password !== "undefined") {
            uri += `:${this.options.password}@`;
        }

        if (typeof this.options.host !== "undefined"
            || typeof this.options.password !== "undefined") {
            if (typeof this.options.host === "undefined") {
                uri += "localhost";
            } else {
                uri += this.options.host;
            }

            if (typeof this.options.port !== "undefined") {
                uri += `:${this.options.port}`;
            }
        }

        if (typeof this.options.db !== "undefined") {
            uri += `/${this.options.db}`;
        }

        return uri;
    }
}

/**
 * `RedisSocketOptions` creates Redis clients that connect to a single database
 * over Unix Socket.
 */
export class RedisSocketOptions implements RedisOptions {
    public readonly options: BasicRedisSocketOptions;

    public constructor(options: BasicRedisSocketOptions) {
        this.options = appendDefaultOptions(options);
    }

    public createClient(override?: object): IoRedis.Redis {
        return new IoRedis(maybeOverride(this.options, override));
    }

    public createUri(): string {
        let uri = "redis";

        if (typeof this.options.tls !== "undefined") {
            uri += "s";
        }

        uri += `+socket://${this.options.path}`;

        if (typeof this.options.password !== "undefined") {
            uri += `?password=${this.options.password}`;
        }

        return uri;
    }
}

/**
 * `RedisSentinelOptions` creates Redis clients that connect to a group of Redis
 * Sentinel nodes, automatically discovering slave nodes in the network.
 */
export class RedisSentinelOptions implements RedisOptions {
    public readonly options: BasicRedisSentinelOptions;

    public constructor(options: BasicRedisSentinelOptions) {
        this.options = appendDefaultOptions(options);
    }

    public createClient(override?: object): IoRedis.Redis {
        return new IoRedis(maybeOverride(this.options, override));
    }

    public createUri(): string {
        throw new UnimplementedError();
    }
}

/**
 * `RedisClusterOptions` creates Redis clients that connect to a Redis
 * Cluster network.
 */
export class RedisClusterOptions implements RedisOptions {
    public readonly options: BasicRedisClusterOptions;

    public constructor(options: BasicRedisClusterOptions) {
        this.options = (() => {
            if (typeof options.redisOptions === "undefined") {
                return options;
            }

            return {
                ...options,
                redisOptions: appendDefaultOptions(options.redisOptions),
            };
        })();
    }

    public createClient(): IoRedis.Redis {
        return new IoRedis.Cluster(this.options.nodes, this.options);
    }

    public createUri(): string {
        throw new UnimplementedError();
    }
}

export const DEFAULT_REDIS_OPTIONS: RedisTcpOptions = new RedisTcpOptions({
    protocol: "redis"
});

/**
 * @param options Options that might be used to construct ioredis clients.
 * @returns A transformed `NativeOptions` object.
 */
export const createOptions = (options: NativeOptions): RedisOptions => {
    if (isCluster(options)) {
        return new RedisClusterOptions(options);
    } else if ((options as BasicRedisSentinelOptions).sentinels) {
        return new RedisSentinelOptions(options as BasicRedisSentinelOptions);
    } else if ((options as BasicRedisSocketOptions).path) {
        return new RedisSocketOptions(options as BasicRedisSocketOptions);
    }

    return new RedisTcpOptions({
        ...(options as BasicRedisTcpOptions),
        protocol: (() => {
            if (options.tls) {
                return "rediss";
            }

            return "redis";
        })(),
    });
};

export type NativeOptions = IoRedis.RedisOptions
                            | BasicRedisClusterOptions;

const isCluster =
    (options: NativeOptions): options is BasicRedisClusterOptions =>
        (options as BasicRedisClusterOptions).nodes !== undefined;