Use a dedicated buildout directory for building a rebootstrap python.

slapos/rebootstrap/__init__.py

@@ -24,13 +24,18 @@ class Rebootstrap:
   def __init__(self, buildout):
     self.logger = logging.getLogger(__name__)
     self.buildout = buildout
+    buildout_directory = buildout['buildout']['directory']
+    self.rebootstrap_directory = os.path.join(
+      buildout_directory, 'rebootstrap'
+    )
     # fetch section to build python, obligatory
     self.python_section = (
       buildout['buildout'].get('python') or \
       buildout['rebootstrap']['section']
     ).strip()
-    self.wanted_python = buildout[self.python_section]['executable']
-
+    self.wanted_python = buildout[self.python_section]['executable'].replace(
+      buildout_directory, self.rebootstrap_directory
+    )
     # query for currently running python
     self.running_python = sys.executable
 
@@ -53,12 +58,12 @@ Buildout will be restarted automatically to have this change applied.
     self.logger.info(message)
     args = map(zc.buildout.easy_install._safe_arg, sys.argv)
     env = os.environ
-    env['ORIG_PYTHON'] = sys.executable
     os.execve(self.wanted_python, [self.wanted_python] + args, env)
 
   def install_section(self):
-    env = os.environ
-    if not os.path.exists(self.wanted_python):
+    # For safety, we always try to install/update instead of the condition
+    # if not os.path.exists(self.wanted_python):
+    if True:
       self.logger.info('Installing section %r to provide %r' % (
         self.python_section, self.wanted_python))
       args = map(zc.buildout.easy_install._safe_arg, sys.argv)
@@ -72,6 +77,8 @@ Buildout will be restarted automatically to have this change applied.
       # rerun buildout with only neeeded section to reuse buildout
       # ability to calcuate all dependency
       args.extend([
+        # chroot to rebootstrap directory
+        'buildout:directory=%s' % self.rebootstrap_directory,
         # install only required section with dependencies
         'buildout:parts=%s' % self.python_section,
         # do not load this extension
@@ -89,26 +96,3 @@ Buildout will be restarted automatically to have this change applied.
           '%r\nUnfortunately even after installing this section executable was'
           ' not found.\nThis is section responsibility to provide python (eg. '
           'by compiling it).' % (self.python_section, self.wanted_python))
-
-_uninstall_part_orig = zc.buildout.buildout.Buildout._uninstall_part
-def _uninstall_part(self, part, installed_part_options):
-  _uninstall_part_orig(self, part, installed_part_options)
-  try:
-    location = self[part].get('location')
-  except zc.buildout.buildout.MissingSection:
-    return
-  if location and sys.executable.startswith(location):
-    message = """
-************ REBOOTSTRAP: IMPORTANT NOTICE ************
-%r part that provides the running Python is uninstalled.
-Buildout will be restarted automatically with the original Python.
-************ REBOOTSTRAP: IMPORTANT NOTICE ************
-""" % part
-    self._logger.info(message)
-    if getattr(self, 'dry_run', False):
-      sys.exit()
-    args = map(zc.buildout.easy_install._safe_arg, sys.argv)
-    env = os.environ
-    orig_python = env['ORIG_PYTHON']
-    os.execve(orig_python, [orig_python] + args, env)
-zc.buildout.buildout.Buildout._uninstall_part = _uninstall_part