From 377435f3eb96e35e7e296e48df64ec42a092b7ad Mon Sep 17 00:00:00 2001
From: Rainer Killinger <killinger@hrz.uni-frankfurt.de>
Date: Tue, 7 Sep 2021 10:20:06 +0200
Subject: [PATCH] refacator: read configuration from env variables

---
 README.md  | 18 ++++++++++++++++--
 src/cli.ts | 30 +++++++++++++++++++++---------
 2 files changed, 37 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index c6588306..8e8fea77 100644
--- a/README.md
+++ b/README.md
@@ -1,23 +1,34 @@
 # minimal-connector
+
 ## Prerequisites
+
 * `node` and `npm` installed
-* a backend, which is running locally (on http://localhost:3000)
+* a backend, which is running locally (e.g. on http://localhost:3000)
+
 ## How to get started
+
 To install all required `npm` packages:
+
 ```shell script
 npm install
 ```
+
 To prepare the script to be executed, run:
+
 ```shell script
 npm run build
 ```
+
 To start the plugin, you need to execute the code in "CLI" script:
+
 ```shell script
 node lib/cli.js run <backendURL> <pluginName> <routeName> <URL> <port>
-e.g.:
+With fallback values being:
 node lib/cli.js run http://localhost:3000 minimal-plugin minimalPlugin http://localhost 4000
 ```
+
 ## Creating your own plugin
+
 * Modify the default values in `cli.ts` to your needs:
   * update the name
   * update the port
@@ -27,8 +38,11 @@ node lib/cli.js run http://localhost:3000 minimal-plugin minimalPlugin http://lo
 * Delete the `sum` function in `minimal-plugin.ts` and write your own logic inside the `onRouteInvoke` function
 * Define the layout of your http requests and responses inside the `/plugin/protocol` folder. The names of the interfaces
 need to be the same as the request and response names you defined in the `cli.ts`
+
 ## Code structure
+
 Folder `src` contains:
+
 * Reference implementations for CLI and a plugin
 * [/cli.ts](src/cli.ts)
   * minimal CLI to start your connector, that uses CLI-args, so that there are no hard coded values for configuration
diff --git a/src/cli.ts b/src/cli.ts
index 084d16a6..bf60f0e0 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019 StApps
+ * Copyright (C) 2019-2021 StApps
  * This program is free software: you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
  * Software Foundation, version 3.
@@ -22,26 +22,38 @@ import {readFileSync} from 'fs';
 import {join, resolve} from 'path';
 import {MinimalPlugin} from './plugin/minimal-plugin';
 
-const pluginVersion = JSON.parse(
-  readFileSync(join(__dirname, '..', 'package.json'))
-    .toString(),
-).version;
 
 process.on('unhandledRejection', (error) => {
   throw error;
 });
 
+const pluginVersion = JSON.parse(
+  readFileSync(join(__dirname, '..', 'package.json'))
+    .toString(),
+).version;
+
 const program = new Command()
   .version(pluginVersion)
   .option('-b, --backend-url <string>', 'URL of the StApps backend deployment', 'http://localhost:3000')
   .option('-n, --plugin-name <string>', 'The name of the plugin', 'minimal-plugin') // TODO: adjust default
-  .option('-r, --route-name <string>', 'The name of the route', 'minimalPlugin') // TODO: adjust default
+  .option('-r, --route-name <string>', 'The name of the route', 'minimalplugin') // TODO: adjust default
   .option('-u, --url <string>', 'The url of the plugin', 'http://localhost') // TODO: adjust default
   .option('-p, --port <number>', 'The port of the plugin', '4000') // TODO: adjust default
   .parse(process.argv);
 
 const options = program.opts();
 
+// read essencial options from ENV variables if available
+if ('STAPPS_BACKEND' in process.env && typeof process.env.STAPPS_BACKEND === 'string')  {
+  options.backendUrl = process.env.STAPPS_BACKEND;
+}
+if ('PLUGIN_URL' in process.env && typeof process.env.PLUGIN_URL === 'string')  {
+  options.url = process.env.PLUGIN_URL;
+}
+if ('PLUGIN_PORT' in process.env && typeof process.env.PLUGIN_PORT === 'string')  {
+  options.port = process.env.PLUGIN_PORT;
+}
+
 // create an instance of the PluginClient
 const pluginClient = new PluginClient(new HttpClient(), options.backendUrl);
 
@@ -52,15 +64,15 @@ const plugin = new MinimalPlugin(
   new Converter(resolve(__dirname, '..', 'src', 'plugin', 'protocol')), // an instance of the converter. Required
   // because your requests and response schemas are defined in the plugin. The path should lead to your request and
   // response interfaces
-  'SCMinimalRequest', // the name of the request interface TODO: adjust
-  'SCMinimalResponse', // the name of the response interface TODO: adjust
+  'SCMinimalRequest', // TODO: adjust name of the request interface
+  'SCMinimalResponse', // TODO: adjust name of the response interface
   JSON.parse(readFileSync(resolve(__dirname, '..', 'package.json'))
     .toString()).version, // get the version of the plugin from the package.json
 );
 
 pluginClient.registerPlugin(plugin)
   .then(() => {
-    Logger.ok('done.');
+    Logger.ok(`Successfully registered plugin '${options.pluginName}' on /${options.urlSegment} .`);
   })
   .catch((err: Error) => {
     throw err;