Allow providing a default value when an environment variable is used.

lib/config.js

@@ -98,12 +98,17 @@ function walkConfig (level) {
   for (var configEntry in level) {
     if (level[configEntry] && level[configEntry].ENV) {
       if (!process.env[level[configEntry].ENV]) {
-        log.verbose(
-          'Environment variable ' + level[configEntry].ENV + ' is empty!'
-        );
+        if (level[configEntry].default !== undefined) {
+          log.verbose('Environment variable ' + level[configEntry].ENV + ' is empty, used provided default value.');
+          level[configEntry] = level[configEntry].default;
+        } else {
+          log.verbose(
+            'Environment variable ' + level[configEntry].ENV + ' is empty!'
+          );
+        }
+      } else {
+        level[configEntry] = process.env[level[configEntry].ENV];
       }
-
-      level[configEntry] = process.env[level[configEntry].ENV];
     } else if (level[configEntry] && typeof level[configEntry] === 'object') {
       level[configEntry] = walkConfig(level[configEntry]);
     }
@@ -120,7 +125,12 @@ exports.loadObject = function (_config, currentEnv) {
   for (var env in config) {
     if (config[env].ENV) {
       if (!process.env[config[env].ENV]) {
-        log.verbose('Environment variable ' + config[env].ENV + ' is empty!');
+        if (config[env].default !== undefined) {
+          log.verbose('Environment variable ' + config[env].ENV + ' is empty, used provided default value.');
+          out[env] = parseDatabaseUrl(config[env].default);
+        } else {
+          log.verbose('Environment variable ' + config[env].ENV + ' is empty!');
+        }
       } else {
         out[env] = parseDatabaseUrl(process.env[config[env].ENV]);
       }

test/config_test.js

@@ -101,6 +101,18 @@ lab.experiment('config', function () {
     }
   );
 
+  lab.experiment(
+    'loading from a file with ENV vars that have defaults set',
+    function () {
+      var _config = config.load(path.join(__dirname, 'database_with_env_using_default.json'), 'prod');
+      lab.test(
+        'should load the default value specified in the config', () => {
+          Code.expect(_config.prod.username).to.equal('defaultUser');
+        }
+      );
+    }
+  );
+
   lab.experiment(
     'loading from a file with ENV URL',
 
@@ -122,6 +134,26 @@ lab.experiment('config', function () {
     }
   );
 
+  lab.experiment(
+    'loading from a file with ENV URL default',
+
+    function () {
+      var configPath = path.join(__dirname, 'database_with_env_url_default.json');
+      var _config = config.load(configPath, 'prod');
+
+      lab.test(
+        'should load a value from the environments', () => {
+          var current = _config.getCurrent();
+          Code.expect(current.settings.driver).to.equal('postgres');
+          Code.expect(current.settings.user).to.equal('uname');
+          Code.expect(current.settings.password).to.equal('pw');
+          Code.expect(current.settings.host).to.equal('server.com');
+          Code.expect(current.settings.database).to.equal('dbname');
+        }
+      );
+    }
+  );
+
   lab.experiment('loading from an URL', function () {
     var databaseUrl = 'postgres://uname:[email protected]/dbname';
     var _config = config.loadUrl(databaseUrl, 'dev');

test/database_with_env_url_default.json

@@ -0,0 +1,3 @@
+{
+  "prod": {"ENV": "BOGUS_ENV_VAR", "default": "postgres://uname:[email protected]/dbname" }
+}

test/database_with_env_using_default.json

@@ -0,0 +1,7 @@
+{
+  "prod": {
+    "driver": "sqlite3",
+    "filename": "prod.db",
+    "username": {"ENV": "BOGUS_ENV_VAR", "default": "defaultUser" }
+  }
+}