refactor(backend): migrate FileCacheService

FileCacheService was still a legacy service extending AdvancedBase. This
commit changes it to extend BaseService and implement the lifecycle
methods consistent with other services. This is a prerequisite for
moving write_overwrite which needs to import the service via
`extension.import` (not possible for legacy services) so that it may
invalidate file cache when a file is written to.

Author: KernelDeimos

src/backend/src/CoreModule.js

@@ -433,18 +433,19 @@ const install = async ({ context, services, app, useapi, modapi }) => {
 
     const { PermissionShortcutService } = require('./services/auth/PermissionShortcutService');
     services.registerService('permission-shortcut', PermissionShortcutService);
+
+    const { FileCacheService } = require('./services/file-cache/FileCacheService');
+    services.registerService('file-cache', FileCacheService);
 };
 
 const install_legacy = async ({ services }) => {
     const { OperationTraceService } = require('./services/OperationTraceService');
     const { ClientOperationService } = require('./services/ClientOperationService');
     const { EngPortalService } = require('./services/EngPortalService');
-    const { FileCacheService } = require('./services/file-cache/FileCacheService');
 
     // === Services which do not yet extend BaseService ===
     // services.registerService('filesystem', FilesystemService);
     services.registerService('operationTrace', OperationTraceService);
-    services.registerService('file-cache', FileCacheService);
     services.registerService('client-operation', ClientOperationService);
     services.registerService('engineering-portal', EngPortalService);
 

src/backend/src/services/CommandService.js

@@ -127,7 +127,18 @@ class CommandService extends BaseService {
     }
 
     registerCommands(serviceName, commands) {
-        if ( ! this.log ) process.exit(1);
+        if ( ! this.log ) {
+            /* eslint-disable */
+            console.error(
+                'CommandService.registerCommands was called before a logger ' +
+                'was initialied. This happens when calling registerCommands ' +
+                'in the "construct" phase instead of the "init" phase. If ' +
+                'you are migrating a legacy service that does not extend ' +
+                'BaseService, maybe the _construct hook is calling init()'
+            );
+            /* eslint-enable */
+            process.exit(1);
+        }
         for (const command of commands) {
             this.log.debug(`registering command ${serviceName}:${command.id}`);
             this.commands_.push(new Command({