AsyncPipe; table schemata; migrations; File logging

src/orm/directive/RollbackDirective.ts

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+import {Directive, OptionDefinition} from '../../cli'
+import {Container, Inject, Injectable} from '../../di'
+import {EventBus} from '../../event/EventBus'
+import {Migrator} from '../migrations/Migrator'
+import {Migrations} from '../services/Migrations'
+import {RollingBackMigrationEvent} from '../migrations/events/RollingBackMigrationEvent'
+import {RolledBackMigrationEvent} from '../migrations/events/RolledBackMigrationEvent'
+import {EventSubscription} from '../../event/types'
+import {NothingToMigrateError} from '../migrations/NothingToMigrateError'
+
+/**
+ * CLI directive that undoes applied migrations using the default Migrator.
+ * @fixme Support dry run mode
+ */
+@Injectable()
+export class RollbackDirective extends Directive {
+    @Inject()
+    protected readonly bus!: EventBus
+
+    @Inject('injector')
+    protected readonly injector!: Container
+
+    @Inject()
+    protected readonly migrations!: Migrations
+
+    /** Event bus subscriptions. */
+    protected subscriptions: EventSubscription[] = []
+
+    getKeywords(): string | string[] {
+        return ['rollback']
+    }
+
+    getDescription(): string {
+        return 'roll-back applied migrations'
+    }
+
+    getOptions(): OptionDefinition[] {
+        return [
+            '--identifier -i {name} | roll-back a specific migration, by identifier',
+        ]
+    }
+
+    getHelpText(): string {
+        return [
+            'Use this command to undo one or more migrations that were applied.',
+            '',
+            'By default, the command will undo all of the migrations applied the last time the migrate command was run.',
+            '',
+            'To undo a specific migration, pass its identifier using the --identifier option.',
+            '',
+        ].join('\n')
+    }
+
+    async handle(): Promise<void> {
+        await this.registerListeners()
+
+        const identifier = this.option('identifier')
+
+        let identifiers
+        if ( identifier ) {
+            identifiers = [identifier]
+        }
+
+        let error
+        try {
+            await (this.injector.make<Migrator>(Migrator)).rollback(identifiers)
+        } catch (e) {
+            if ( e instanceof NothingToMigrateError ) {
+                this.info(e.message)
+            } else {
+                error = e
+                this.error(e)
+            }
+        } finally {
+            await this.removeListeners()
+        }
+
+        if ( error ) {
+            throw error
+        }
+    }
+
+    /**
+     * Register event-bus listeners to print messages for the user.
+     * @protected
+     */
+    protected async registerListeners(): Promise<void> {
+        this.subscriptions.push(await this.bus.subscribe(RollingBackMigrationEvent, event => {
+            this.info(`Rolling-back migration ${event.migration.identifier}...`)
+        }))
+
+        this.subscriptions.push(await this.bus.subscribe(RolledBackMigrationEvent, event => {
+            this.success(`Rolled-back migration: ${event.migration.identifier}`)
+        }))
+    }
+
+    /** Remove event bus listeners before finish. */
+    protected async removeListeners(): Promise<void> {
+        await Promise.all(this.subscriptions.map(x => x.unsubscribe()))
+        this.subscriptions = []
+    }
+}