--- a/buttercup/buttercup.py	Tue Nov 03 07:51:52 2020 -0800
+++ b/buttercup/buttercup.py	Tue Nov 03 07:59:36 2020 -0800
@@ -2,6 +2,8 @@
 the flower blooming to k0s.org
 """
 
+# TODO: this should all go in a `pip` requirements file
+
 import os
 from subprocess import check_call as call
 from . import source
@@ -52,13 +54,12 @@
               'wordstream',
               'wsgintegrate']
 
-    def __init__(self, srcdir):
+    def __init__(self, srcdir, prefix=None):
         self.srcdir = srcdir
-
-        # TODO: this should all go in a `pip` requirements file
+        self.prefix = prefix or self.HG
 
         # base webapps and dependencies
-        self.sources = {'hg': ['%s/%s' % (self.HG, package)
+        self.sources = {'hg': ['%s/%s' % (self.prefix, package)
                                for package in self.PACKAGES ]}
         self.sources['git'] = []