feat: add ability to merge config files

Author: minottic

.gitignore

@@ -56,4 +56,8 @@ Thumbs.db
 .angular
 
 # karma
-karma-junit.xml
+karma-junit.xml
+
+# config files overrides
+config.override.json
+config.override.*.json

src/app/app-config.service.spec.ts

@@ -5,7 +5,7 @@ import {
   AppConfigService,
   HelpMessages,
 } from "app-config.service";
-import { of } from "rxjs";
+import { Observable, of } from "rxjs";
 import { MockHttp } from "shared/MockStubs";
 
 const appConfig: AppConfigInterface = {
@@ -280,6 +280,47 @@ describe("AppConfigService", () => {
   });
 
   describe("#getConfig()", () => {
+    const mockConfigResponses: Record<string, object> = {
+      "/assets/config.json": {
+        accessTokenPrefix: "",
+        lbBaseURL: "http://127.0.0.1:3000",
+        gettingStarted: null,
+        mainMenu: { nonAuthenticatedUser: { datasets: true } },
+      },
+      "/assets/config.0.json": { accessTokenPrefix: "Bearer " },
+      "/assets/config.override.json": {
+        gettingStarted: "aGettingStarted",
+        addDatasetEnabled: true,
+        mainMenu: { nonAuthenticatedUser: { files: true } },
+      },
+      "/assets/config.override.0.json": { siteTitle: "Test title" },
+    };
+
+    const mergedConfig = {
+      accessTokenPrefix: "Bearer ",
+      lbBaseURL: "http://127.0.0.1:3000",
+      gettingStarted: "aGettingStarted",
+      addDatasetEnabled: true,
+      siteTitle: "Test title",
+      mainMenu: { nonAuthenticatedUser: { datasets: true, files: true } },
+    };
+
+    const mockHttpGet = (backendError = false) => {
+      spyOn(service["http"], "get").and.callFake(
+        (url: string): Observable<any> => {
+          if (url === "/api/v3/admin/config") {
+            if (backendError) {
+              return new Observable((sub) =>
+                sub.error(new Error("No config in backend")),
+              );
+            }
+            return of(mergedConfig);
+          }
+          return of(mockConfigResponses[url] || {});
+        },
+      );
+    };
+
     it("should return the AppConfig object", async () => {
       spyOn(service["http"], "get").and.returnValue(of(appConfig));
       await service.loadAppConfig();
@@ -288,5 +329,29 @@ describe("AppConfigService", () => {
 
       expect(config).toEqual(appConfig);
     });
+
+    it("should merge multiple config JSONs", async () => {
+      mockHttpGet();
+      const config = await service["mergeConfig"]();
+      expect(config).toEqual(mergedConfig);
+    });
+
+    it("should return the merged appConfig", async () => {
+      mockHttpGet(true);
+      await service.loadAppConfig();
+
+      expect(service["appConfig"]).toEqual(
+        jasmine.objectContaining(mergedConfig),
+      );
+      expect(service["http"].get).toHaveBeenCalledWith("/api/v3/admin/config");
+      expect(service["http"].get).toHaveBeenCalledWith("/assets/config.json");
+      expect(service["http"].get).toHaveBeenCalledWith("/assets/config.0.json");
+      expect(service["http"].get).toHaveBeenCalledWith(
+        "/assets/config.override.json",
+      );
+      expect(service["http"].get).toHaveBeenCalledWith(
+        "/assets/config.override.0.json",
+      );
+    });
   });
 });

src/app/app-config.service.ts

@@ -1,6 +1,8 @@
 import { HttpClient } from "@angular/common/http";
 import { Injectable } from "@angular/core";
-import { timeout } from "rxjs/operators";
+import { merge } from "lodash-es";
+import { firstValueFrom, forkJoin, of } from "rxjs";
+import { catchError, timeout } from "rxjs/operators";
 import {
   DatasetDetailComponentConfig,
   DatasetsListSettings,
@@ -156,9 +158,35 @@ function isMainPageConfiguration(obj: any): obj is MainPageConfiguration {
 })
 export class AppConfigService {
   private appConfig: object = {};
+  private configsSize = 4;
 
   constructor(private http: HttpClient) {}
 
+  private async loadAndMerge(files: string[]): Promise<object> {
+    const requests = files.map((f) =>
+      this.http.get(`/assets/${f}`).pipe(catchError(() => of({}))),
+    );
+    const configs = await firstValueFrom(forkJoin(requests));
+    return configs.reduce((acc, cfg) => merge(acc, cfg), {});
+  }
+
+  private async mergeConfig(): Promise<object> {
+    const normalConfigFiles = Array.from(
+      { length: this.configsSize },
+      (_, i) => `config.${i}.json`,
+    );
+    const overrideConfigFiles = Array.from(
+      { length: this.configsSize },
+      (_, i) => `config.override.${i}.json`,
+    );
+    return await this.loadAndMerge([
+      "config.json",
+      ...normalConfigFiles,
+      "config.override.json",
+      ...overrideConfigFiles,
+    ]);
+  }
+
   async loadAppConfig(): Promise<void> {
     try {
       const config = await this.http
@@ -169,7 +197,7 @@ export class AppConfigService {
     } catch (err) {
       console.log("No config available in backend, trying with local config.");
       try {
-        const config = await this.http.get("/assets/config.json").toPromise();
+        const config = await this.mergeConfig();
         this.appConfig = Object.assign({}, this.appConfig, config);
       } catch (err) {
         console.error("No config provided.");