From 6c194b58eb2987a5196ecfd36d4425f4b613683d Mon Sep 17 00:00:00 2001
From: sblausten <sam@roadie.io>
Date: Tue, 5 Jul 2022 17:39:26 +0200
Subject: [PATCH] Make FactRetrieverRegistry async so that a db backed
 implementation can be used

Signed-off-by: sblausten <sam@roadie.io>
---
 .../service/fact/FactRetrieverEngine.test.ts  |  4 +-
 .../src/service/fact/FactRetrieverEngine.ts   | 11 ++----
 .../src/service/fact/FactRetrieverRegistry.ts | 39 ++++++++++++-------
 3 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/plugins/tech-insights-backend/src/service/fact/FactRetrieverEngine.test.ts b/plugins/tech-insights-backend/src/service/fact/FactRetrieverEngine.test.ts
index 454711171f..44ffa6587f 100644
--- a/plugins/tech-insights-backend/src/service/fact/FactRetrieverEngine.test.ts
+++ b/plugins/tech-insights-backend/src/service/fact/FactRetrieverEngine.test.ts
@@ -206,9 +206,7 @@ describe('FactRetrieverEngine', () => {
         { ...testFactRetriever, handler },
       );
       await engine.schedule();
-      const job: FactRetrieverRegistration = engine.getJobRegistration(
-        testFactRetriever.id,
-      );
+      const job = await engine.getJobRegistration(testFactRetriever.id);
       expect(job.cadence!!).toEqual(defaultCadence);
 
       await engine.triggerJob(job.factRetriever.id);
diff --git a/plugins/tech-insights-backend/src/service/fact/FactRetrieverEngine.ts b/plugins/tech-insights-backend/src/service/fact/FactRetrieverEngine.ts
index 25e7610809..f8ff3762dd 100644
--- a/plugins/tech-insights-backend/src/service/fact/FactRetrieverEngine.ts
+++ b/plugins/tech-insights-backend/src/service/fact/FactRetrieverEngine.ts
@@ -66,11 +66,8 @@ export class FactRetrieverEngine {
       defaultTimeout,
     } = options;
 
-    await Promise.all(
-      factRetrieverRegistry
-        .listRetrievers()
-        .map(it => repository.insertFactSchema(it)),
-    );
+    const retrievers = await factRetrieverRegistry.listRetrievers();
+    await Promise.all(retrievers.map(it => repository.insertFactSchema(it)));
 
     return new FactRetrieverEngine(
       repository,
@@ -84,7 +81,7 @@ export class FactRetrieverEngine {
   }
 
   async schedule() {
-    const registrations = this.factRetrieverRegistry.listRegistrations();
+    const registrations = await this.factRetrieverRegistry.listRegistrations();
     const newRegs: string[] = [];
 
     await Promise.all(
@@ -115,7 +112,7 @@ export class FactRetrieverEngine {
     );
   }
 
-  getJobRegistration(ref: string): FactRetrieverRegistration {
+  getJobRegistration(ref: string): Promise<FactRetrieverRegistration> {
     return this.factRetrieverRegistry.get(ref);
   }
 
diff --git a/plugins/tech-insights-backend/src/service/fact/FactRetrieverRegistry.ts b/plugins/tech-insights-backend/src/service/fact/FactRetrieverRegistry.ts
index 504d561f17..1ad7626e8e 100644
--- a/plugins/tech-insights-backend/src/service/fact/FactRetrieverRegistry.ts
+++ b/plugins/tech-insights-backend/src/service/fact/FactRetrieverRegistry.ts
@@ -26,16 +26,21 @@ import { ConflictError, NotFoundError } from '@backstage/errors';
  *
  */
 export interface FactRetrieverRegistry {
-  readonly retrievers: Map<string, FactRetrieverRegistration>;
-  register(registration: FactRetrieverRegistration): void;
-  get(retrieverReference: string): FactRetrieverRegistration;
-  listRetrievers(): FactRetriever[];
-  listRegistrations(): FactRetrieverRegistration[];
-  getSchemas(): FactSchema[];
+  register(registration: FactRetrieverRegistration): Promise<void>;
+  get(retrieverReference: string): Promise<FactRetrieverRegistration>;
+  listRetrievers(): Promise<FactRetriever[]>;
+  listRegistrations(): Promise<FactRetrieverRegistration[]>;
+  getSchemas(): Promise<FactSchema[]>;
 }
 
+/**
+ * A basic in memory fact retriever registry.
+ *
+ * You can replace this with a persistance based version using the FactRetrieverRegistry interface.
+ *
+ */
 export class DefaultFactRetrieverRegistry implements FactRetrieverRegistry {
-  readonly retrievers = new Map<string, FactRetrieverRegistration>();
+  private readonly retrievers = new Map<string, FactRetrieverRegistration>();
 
   constructor(retrievers: FactRetrieverRegistration[]) {
     retrievers.forEach(it => {
@@ -50,27 +55,31 @@ export class DefaultFactRetrieverRegistry implements FactRetrieverRegistry {
       );
     }
     this.retrievers.set(registration.factRetriever.id, registration);
+    return Promise.resolve();
   }
 
-  get(retrieverReference: string): FactRetrieverRegistration {
+  get(retrieverReference: string): Promise<FactRetrieverRegistration> {
     const registration = this.retrievers.get(retrieverReference);
     if (!registration) {
       throw new NotFoundError(
         `Tech insight fact retriever with identifier '${retrieverReference}' is not registered.`,
       );
     }
-    return registration;
+    return Promise.resolve(registration);
   }
 
-  listRetrievers(): FactRetriever[] {
-    return [...this.retrievers.values()].map(it => it.factRetriever);
+  listRetrievers(): Promise<FactRetriever[]> {
+    return Promise.resolve(
+      [...this.retrievers.values()].map(it => it.factRetriever),
+    );
   }
 
-  listRegistrations(): FactRetrieverRegistration[] {
-    return [...this.retrievers.values()];
+  listRegistrations(): Promise<FactRetrieverRegistration[]> {
+    return Promise.resolve([...this.retrievers.values()]);
   }
 
-  getSchemas(): FactSchema[] {
-    return this.listRetrievers().map(it => it.schema);
+  async getSchemas(): Promise<FactSchema[]> {
+    const retrievers = await this.listRetrievers();
+    return Promise.resolve(retrievers.map(it => it.schema));
   }
 }