Just use the current server as the registry server, this will work for all externally available addresses.

config.py

@@ -103,7 +103,6 @@ class BuildNodeConfig(object):
 class DebugConfig(FlaskConfig, MailConfig, LocalStorage, SQLiteDB,
                   StripeTestConfig, MixpanelTestConfig, GitHubTestConfig,
                   DigitalOceanConfig, AWSCredentials, BuildNodeConfig):
-  REGISTRY_SERVER = 'localhost:5000'
   LOGGING_CONFIG = {
     'level': logging.DEBUG,
     'format': LOG_FORMAT
@@ -117,7 +116,6 @@ class LocalHostedConfig(FlaskConfig, MailConfig, S3Storage, RDSMySQL,
                         StripeLiveConfig, MixpanelTestConfig,
                         GitHubProdConfig, DigitalOceanConfig,
                         BuildNodeConfig):
-  REGISTRY_SERVER = 'localhost:5000'
   LOGGING_CONFIG = {
     'level': logging.DEBUG,
     'format': LOG_FORMAT
@@ -128,7 +126,6 @@ class LocalHostedConfig(FlaskConfig, MailConfig, S3Storage, RDSMySQL,
 class ProductionConfig(FlaskConfig, MailConfig, S3Storage, RDSMySQL,
                        StripeLiveConfig, MixpanelProdConfig,
                        GitHubProdConfig, DigitalOceanConfig, BuildNodeConfig):
-  REGISTRY_SERVER = 'quay.io'
   LOGGING_CONFIG = {
     'stream': sys.stderr,
     'level': logging.DEBUG,

endpoints/index.py

@@ -2,6 +2,7 @@ import json
 import urllib
 import json
 import logging
+import urlparse
 
 from flask import request, make_response, jsonify, abort
 from functools import wraps
@@ -25,7 +26,9 @@ def generate_headers(role='read'):
     def wrapper(namespace, repository, *args, **kwargs):
       response = f(namespace, repository, *args, **kwargs)
 
-      response.headers['X-Docker-Endpoints'] = app.config['REGISTRY_SERVER']
+      # We run our index and registry on the same hosts for now
+      registry_server = urlparse.urlparse(request.url).netloc
+      response.headers['X-Docker-Endpoints'] = registry_server
 
       has_token_request = request.headers.get('X-Docker-Token', '')