Import other modules into monorepo

src/orm/DatabaseService.ts

@@ -0,0 +1,68 @@
+import {Connection} from "./connection/Connection";
+import {Inject, Singleton} from "../di";
+import {ErrorWithContext, uuid_v4} from "../util";
+import {AppClass} from "../lifecycle/AppClass";
+import {Logging} from "../service/Logging";
+
+/**
+ * A singleton, non-unit service that stores and retrieves database connections by name.
+ */
+@Singleton()
+export class DatabaseService extends AppClass {
+    @Inject()
+    protected logging!: Logging
+
+    /** Mapping of connection name -> connection instance for connections registered with this service. */
+    protected readonly connections: { [key: string]: Connection } = {}
+
+    /**
+     * Register a new connection instance by name.
+     * @param name
+     * @param connection
+     */
+    register(name: string, connection: Connection) {
+        if ( this.connections[name] ) {
+            this.logging.warn(`Overriding duplicate connection: ${name}`)
+        }
+
+        this.connections[name] = connection
+    }
+
+    /**
+     * Returns true if a connection is registered with the given name.
+     * @param name
+     */
+    has(name: string) {
+        return !!this.connections[name]
+    }
+
+    /**
+     * Get a connection instance by its name. Throws if none exists.
+     * @param name
+     */
+    get(name: string): Connection {
+        if ( !this.has(name) ) {
+            throw new ErrorWithContext(`No such connection is registered: ${name}`)
+        }
+
+        return this.connections[name]
+    }
+
+    /**
+     * Return an array of the names of all registered connections.
+     */
+    names(): string[] {
+        return Object.keys(this.connections)
+    }
+
+    /** Get a guaranteed-unique connection name. */
+    uniqueName(): string {
+        let name: string;
+
+        do {
+            name = uuid_v4()
+        } while (this.has(name))
+
+        return name
+    }
+}