Load configuration data from environment variables

domains/configuration-data.js

@@ -0,0 +1,25 @@
+class ConfigurationData {
+  get MongoDBUrl() {
+    return this.mongoDBUrl;
+  }
+  set MongoDBUrl(url) {
+    this.mongoDBUrl = url;
+  }
+  get NodeEnv() {
+    return this.nodeEnv;
+  }
+  set NodeEnv(environment) {
+    this.nodeEnv = environment;
+  }
+
+  toString() {
+    const output = {
+      MongoDBUrl: this.MongoDBUrl,
+      NodeEnv: this.NodeEnv,
+    };
+
+    return JSON.stringify(output, null, 2);
+  }
+}
+
+module.exports = ConfigurationData;

infrastructures/environment-variables.js

@@ -0,0 +1,19 @@
+/**
+ * Environment variable class is responsible for loading environment variables
+ * from process and/or operating system so it is available to be used in
+ * this application
+ */
+const ConfigurationData = require('../domains/configuration-data');
+
+class EnvironmentVariable {
+  load() {
+    const configurationData = new ConfigurationData();
+
+    configurationData.MongoDBUrl = process.env.MONGODB_URL;
+    configurationData.NodeEnv = process.env.NODE_ENV;
+
+    return configurationData;
+  }
+}
+
+module.exports = EnvironmentVariable;

interfaces/configuration.js

@@ -0,0 +1,11 @@
+class Configuration {
+  constructor(options) {
+    this.configurationAdapter = options.ConfigurationAdapter;
+  }
+
+  load() {
+    return this.configurationAdapter.load();
+  }
+}
+
+module.exports = Configuration;

server.js

@@ -1,7 +1,25 @@
-const VersionInteractor = require('./usecases/version');
-const WebServerInterface = require('./interfaces/webserver');
+const EnvironmentVariables = require('./infrastructures/environment-variables');
 const ExpressWebServer = require('./infrastructures/express-server');
 
+const ConfigurationAdapter = require('./interfaces/configuration');
+const WebServerInterface = require('./interfaces/webserver');
+
+const ConfigurationInteractor = require('./usecases/configuration');
+const VersionInteractor = require('./usecases/version');
+
+const environmentVariable = new EnvironmentVariables();
+
+const configurationAdapter = new ConfigurationAdapter({
+  ConfigurationAdapter: environmentVariable,
+});
+
+const configurationInteractor = new ConfigurationInteractor({
+  ConfigurationInterface: configurationAdapter,
+});
+
+const configuraionData = configurationInteractor.load();
+console.log(configuraionData.toString());
+
 const versionInteractor = new VersionInteractor();
 const webserverInterface = new WebServerInterface({
   VersionInteractor: versionInteractor,

usecases/configuration.js

@@ -0,0 +1,10 @@
+class Configuration {
+  constructor(options) {
+    this.configurationInterface = options.ConfigurationInterface;
+  }
+  load() {
+    return this.configurationInterface.load();
+  }
+}
+
+module.exports = Configuration;