refactor: build system

backend/proxy/src/app.ts

@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2022 StApps
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+import {Logger} from '@openstapps/logger';
+import {execSync} from 'child_process';
+import * as Dockerode from 'dockerode';
+import mustache from 'mustache';
+import {asyncReadFile, asyncWriteFile} from './common.js';
+import {getContainers, getTemplateView} from './main.js';
+
+/* eslint-disable unicorn/prefer-module */
+
+// handle unhandled promise rejections
+process.on('unhandledRejection', async error => {
+  await Logger.error(error);
+  process.exit(1);
+});
+
+let containerHashCache = '';
+let configHashCache = '';
+const delay = (ms: number) => new Promise(resolve => setTimeout(resolve, ms));
+
+/**
+ * Reads the container information from the docker socket and updates the nginx config if necessary
+ */
+async function updateNginxConfig() {
+  const containers = await getContainers();
+
+  const containerHash = containers
+    .map((container: Dockerode.ContainerInfo) => {
+      return container.Id;
+    })
+    .join(',');
+
+  delete require.cache[require.resolve('config')];
+  // eslint-disable-next-line @typescript-eslint/no-var-requires
+  const configFile = require('config');
+  const configHash = JSON.stringify(configFile);
+
+  // if containers changed -> write config file, reload nginx
+  if (containerHash !== containerHashCache || configHash !== configHashCache) {
+    Logger.log('Generating new NGINX configuration');
+    Logger.log('Waiting for Docker network to settle...');
+    await delay(10_000);
+
+    // render nginx config file
+    const nginxConfig = mustache.render(
+      await asyncReadFile('nginx.conf.template', 'utf8'),
+      await getTemplateView(containers),
+    );
+
+    containerHashCache = containerHash;
+    configHashCache = configHash;
+
+    Logger.log(`Writing new config file "${configFile.output}"`);
+
+    // overwrite nginx config file with our rendered one
+    await asyncWriteFile(configFile.output, nginxConfig, 'utf8');
+
+    Logger.log('Executing "nginx -s reload" to tell nginx to reload the configuration file');
+
+    execSync('nginx -s reload');
+  }
+
+  // set timeout to update configuration again in 30s
+  setTimeout(updateNginxConfig, 30_000);
+}
+
+// start the process that checks the docker socket periodically
+// eslint-disable-next-line unicorn/prefer-top-level-await
+updateNginxConfig();