From d4e8ae4a03b820285335fcea7eae63d7820af848 Mon Sep 17 00:00:00 2001
From: Kevin Puventhiranathan <kevinpuventhiranathan@economist.com>
Date: Tue, 1 Oct 2019 16:14:40 +0100
Subject: [PATCH] record name of variable used to get env var & use this in
 error messages for strict mode.

---
 lib/config.js         | 29 ++++++++++++++++++++++-------
 test/6-strict-mode.js | 26 ++++++++++++++++++++++++--
 2 files changed, 46 insertions(+), 9 deletions(-)

diff --git a/lib/config.js b/lib/config.js
index b5c306c1..d1a69b2c 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -15,7 +15,7 @@ var deferConfig = require('../defer').deferConfig,
 // Static members
 var DEFAULT_CLONE_DEPTH = 20,
     NODE_CONFIG, CONFIG_DIR, RUNTIME_JSON_FILENAME, NODE_ENV, APP_INSTANCE,
-    HOST, HOSTNAME, ALLOW_CONFIG_MUTATIONS, CONFIG_SKIP_GITCRYPT,
+    HOST, HOSTNAME, ALLOW_CONFIG_MUTATIONS, CONFIG_SKIP_GITCRYPT, NODE_ENV_VAR_NAME,
     NODE_CONFIG_PARSER,
     env = {},
     privateUtil = {},
@@ -510,11 +510,26 @@ util.loadFileConfigs = function(configDir) {
   var t = this,
       config = {};
 
-  // Initialize parameters from command line, environment, or default
-  NODE_ENV = util.initParam('NODE_ENV', 'development');
+  // Specify variables that can be used to define the environment
+  var node_env_var_names = ['NODE_CONFIG_ENV', 'NODE_ENV'];
 
-  // Override, NODE_ENV if NODE_CONFIG_ENV is specified.
-  NODE_ENV = util.initParam('NODE_CONFIG_ENV', NODE_ENV);
+  // Loop through the variables to try and set environment
+  for (node_env_var_name of node_env_var_names) {
+    NODE_ENV = util.initParam(node_env_var_name);
+    if (!!NODE_ENV) {
+      NODE_ENV_VAR_NAME = node_env_var_name;
+      break;
+    }
+  }
+
+  // If we haven't successfully set the environment using the variables, we'll default it
+  if (!NODE_ENV) {
+    NODE_ENV = 'development';
+  }
+
+  node_env_var_names.forEach(node_env_var_name => {
+    env[node_env_var_name] = NODE_ENV;
+  });
 
   // Split files name, for loading multiple files.
   NODE_ENV = NODE_ENV.split(',');
@@ -1395,11 +1410,11 @@ util.runStrictnessChecks = function (config) {
     });
     // development is special-cased because it's the default value
     if (env && (env !== 'development') && !anyFilesMatchEnv) {
-      _warnOrThrow("NODE_ENV value of '"+env+"' did not match any deployment config file names.");
+      _warnOrThrow(NODE_ENV_VAR_NAME+" value of '"+env+"' did not match any deployment config file names.");
     }
     // Throw if NODE_ENV matches' default' or 'local'
     if ((env === 'default') || (env === 'local')) {
-      _warnOrThrow("NODE_ENV value of '"+env+"' is ambiguous.");
+      _warnOrThrow(NODE_ENV_VAR_NAME+" value of '"+env+"' is ambiguous.");
     }
   });
 
diff --git a/test/6-strict-mode.js b/test/6-strict-mode.js
index 5cbd36e3..b5257dbb 100644
--- a/test/6-strict-mode.js
+++ b/test/6-strict-mode.js
@@ -54,6 +54,20 @@ vows.describe('Tests for strict mode').addBatch({
     exceptionMessage :"FATAL: NODE_ENV value of 'local' is ambiguous. "
                      +"See https://github.com/lorenwest/node-config/wiki/Strict-Mode",
   }),
+
+  "Specifying reserved word for NODE_CONFIG_ENV throws reserved word exception with appropriate wording": _expectException({
+    NODE_CONFIG_ENV  : 'local',
+    APP_INSTANCE     : 'valid-instance',
+    exceptionMessage :"FATAL: NODE_CONFIG_ENV value of 'local' is ambiguous. "
+                     +"See https://github.com/lorenwest/node-config/wiki/Strict-Mode",
+  }),
+
+  "Specifying NODE_CONFIG_ENV=production,cloud with no cloud file throws an exception with appropriate wording": _expectException({
+    NODE_CONFIG_ENV  : 'cloud',
+    APP_INSTANCE     : 'valid-instance',
+    exceptionMessage :"FATAL: NODE_CONFIG_ENV value of 'cloud' did not match any deployment config file names. "
+                     +"See https://github.com/lorenwest/node-config/wiki/Strict-Mode",
+  }),
 })
 .export(module);
 
@@ -67,9 +81,17 @@ function _expectException (opts) {
       process.env.NODE_CONFIG_DIR         = __dirname + '/6-config';
       process.env.NODE_CONFIG_STRICT_MODE = 1;
       process.env.NODE_APP_INSTANCE       = opts.APP_INSTANCE;
-      process.env.NODE_ENV                = opts.NODE_ENV;
+
+      if (!!opts.NODE_ENV) {
+        process.env.NODE_ENV              = opts.NODE_ENV;
+      }
+
+      if (!!opts.NODE_CONFIG_ENV) {
+        process.env.NODE_CONFIG_ENV       = opts.NODE_CONFIG_ENV;
+      }
+
       delete process.env.NODE_CONFIG;
-      try { 
+      try {
         var config = requireUncached(__dirname + '/../lib/config');
       }
       catch (e) {