Add support for jobs & queueables, migrations

- Create migration directives & migrators
- Modify Cache classes to support array manipulation
- Create Redis unit and RedisCache implementation
- Create Queueable base class and Queue class that uses Cache backend

src/support/redis/Redis.ts

@@ -0,0 +1,75 @@
+import {Inject, Singleton} from '../../di'
+import {Config} from '../../service/Config'
+import * as IORedis from 'ioredis'
+import {RedisOptions} from 'ioredis'
+import {Logging} from '../../service/Logging'
+import {Unit} from '../../lifecycle/Unit'
+import {AsyncPipe} from '../../util'
+
+export {RedisOptions} from 'ioredis'
+
+/**
+ * Unit that loads configuration for and manages instantiation
+ * of an IORedis connection.
+ */
+@Singleton()
+export class Redis extends Unit {
+    /** The config service. */
+    @Inject()
+    protected readonly config!: Config
+
+    /** The loggers. */
+    @Inject()
+    protected readonly logging!: Logging
+
+    /**
+     * The instantiated connection, if one exists.
+     * @private
+     */
+    private connection?: IORedis.Redis
+
+    async up(): Promise<void> {
+        this.logging.info('Attempting initial connection to Redis...')
+        this.logging.debug('Config:')
+        this.logging.debug(Config)
+        this.logging.debug(this.config)
+        await this.getConnection()
+    }
+
+    async down(): Promise<void> {
+        this.logging.info('Disconnecting Redis...')
+        if ( this.connection?.status === 'ready' ) {
+            await this.connection.disconnect()
+        }
+    }
+
+    /**
+     * Get the IORedis connection instance.
+     */
+    public async getConnection(): Promise<IORedis.Redis> {
+        if ( !this.connection ) {
+            const options = this.config.get('redis.connection') as RedisOptions
+            this.logging.verbose(options)
+            this.connection = new IORedis(options)
+        }
+
+        return this.connection
+    }
+
+    /**
+     * Get the IORedis connection in an AsyncPipe.
+     */
+    public pipe(): AsyncPipe<IORedis.Redis> {
+        return new AsyncPipe<IORedis.Redis>(() => this.getConnection())
+    }
+
+    /**
+     * Get an IORedis.Pipeline instance in an AsyncPipe.
+     */
+    public multi(): AsyncPipe<IORedis.Pipeline> {
+        return this.pipe()
+            .tap(redis => {
+                return redis.multi()
+            })
+    }
+}