feat: log global.GLOBAL_AGENT configuration changes

src/factories/createGlobalAgentGlobal.js

@@ -0,0 +1,42 @@
+// @flow
+
+import Logger from '../Logger';
+
+const log = Logger.child({
+  namespace: 'bootstrap'
+});
+
+const KNOWN_PROPERTY_NAMES = [
+  'bootstrapped',
+  'HTTP_PROXY',
+  'HTTPS_PROXY',
+  'NO_PROXY'
+];
+
+export default () => {
+  // eslint-disable-next-line fp/no-proxy
+  return new Proxy({
+    bootstrapped: false,
+    HTTP_PROXY: '',
+    HTTPS_PROXY: '',
+    NO_PROXY: ''
+  }, {
+    set: (subject, name, value) => {
+      if (!KNOWN_PROPERTY_NAMES.includes(name)) {
+        throw new Error('Cannot set an unmapped property "' + name + '".');
+      }
+
+      subject[name] = value;
+
+      log.info({
+        change: {
+          name,
+          value
+        },
+        newConfiguration: subject
+      }, 'configuration changed');
+
+      return true;
+    }
+  });
+};

src/factories/index.js

@@ -0,0 +1,3 @@
+// @flow
+
+export {default as createGlobalAgentGlobal} from './createGlobalAgentGlobal';

src/routines/bootstrap.js

@@ -12,6 +12,9 @@ import {
 import {
   UnexpectedStateError
 } from '../errors';
+import {
+  createGlobalAgentGlobal
+} from '../factories';
 import {
   bindHttpMethod,
   isUrlMatchingNoProxy,
@@ -43,7 +46,7 @@ const createConfiguration = (configurationInput: ConfigurationInputType): Config
 export default (configurationInput: ConfigurationInputType) => {
   const configuration = createConfiguration(configurationInput);
 
-  global.GLOBAL_AGENT = global.GLOBAL_AGENT || {};
+  global.GLOBAL_AGENT = global.GLOBAL_AGENT || createGlobalAgentGlobal();
 
   if (global.GLOBAL_AGENT.bootstrapped) {
     log.warn('found global.globalAgent; second attempt to bootstrap global-agent was ignored');

test/global-agent/factories/createGlobalAgentGlobal.js

@@ -0,0 +1,51 @@
+// @flow
+
+import test from 'ava';
+import createGlobalAgentGlobal from '../../../src/factories/createGlobalAgentGlobal';
+
+test('defaults bootstrapped to false', (t) => {
+  const globalAgentGlobal = createGlobalAgentGlobal();
+
+  t.is(globalAgentGlobal.bootstrapped, false);
+});
+
+test('sets bootstrapped', (t) => {
+  const globalAgentGlobal = createGlobalAgentGlobal();
+
+  globalAgentGlobal.bootstrapped = true;
+
+  t.is(globalAgentGlobal.bootstrapped, true);
+});
+
+test('sets HTTP_PROXY', (t) => {
+  const globalAgentGlobal = createGlobalAgentGlobal();
+
+  globalAgentGlobal.HTTP_PROXY = 'http://127.0.0.1';
+
+  t.is(globalAgentGlobal.HTTP_PROXY, 'http://127.0.0.1');
+});
+
+test('sets HTTPS_PROXY', (t) => {
+  const globalAgentGlobal = createGlobalAgentGlobal();
+
+  globalAgentGlobal.HTTPS_PROXY = 'http://127.0.0.1';
+
+  t.is(globalAgentGlobal.HTTPS_PROXY, 'http://127.0.0.1');
+});
+
+test('sets NO_PROXY', (t) => {
+  const globalAgentGlobal = createGlobalAgentGlobal();
+
+  globalAgentGlobal.NO_PROXY = '*';
+
+  t.is(globalAgentGlobal.NO_PROXY, '*');
+});
+
+test('throws an error if unknown property is set', (t) => {
+  const globalAgentGlobal = createGlobalAgentGlobal();
+
+  t.throws(() => {
+    // $FlowFixMe
+    globalAgentGlobal.FOO = 'BAR';
+  }, 'Cannot set an unmapped property "FOO".');
+});