prevent distutils during module install from downloading and load pth files

based on a patch by Cillian de Róiste

svn path=/nixpkgs/branches/stdenv-updates/; revision=32583

pkgs/development/python-modules/generic/default.nix

@@ -3,7 +3,7 @@
    (http://pypi.python.org/pypi/setuptools/), which represents a large
    number of Python packages nowadays.  */
 
-{ python, setuptools, wrapPython, lib, site }:
+{ python, setuptools, wrapPython, lib, site, offlineDistutils }:
 
 { name, namePrefix ? "python-"
 
@@ -69,6 +69,15 @@ python.stdenv.mkDerivation (attrs // {
 
   buildInputs = [ python wrapPython setuptools ] ++ buildInputs ++ pythonPath;
 
+  configurePhase = ''
+    # do not allow distutils to make downloads, whatever install command is used
+    export PYTHONPATH="${setuptools}/lib/${python.libPrefix}:$PYTHONPATH"
+    export PYTHONPATH="${offlineDistutils}/lib/${python.libPrefix}:$PYTHONPATH"
+
+    # enable pth files for dependencies
+    export PYTHONPATH="${site}/lib/${python.libPrefix}/site-packages:$PYTHONPATH"
+  '';
+
   # XXX: I think setuptools is not needed here
   pythonPath = [ setuptools site ] ++ pythonPath;
 

pkgs/development/python-modules/offline-distutils/default.nix

@@ -0,0 +1,21 @@
+# Used during module installation to prevent easy_install and python
+# setup.py install/test from downloading
+
+{ stdenv, python }:
+
+stdenv.mkDerivation {
+  name = "python-offline-distutils-${python.version}";
+
+  buildInputs = [ python ];
+
+  unpackPhase = "true";
+  installPhase = ''
+    dst="$out/lib/${python.libPrefix}"
+    ensureDir $dst/distutils
+    ln -s ${python}/lib/${python.libPrefix}/distutils/* $dst/distutils/
+    cat <<EOF > $dst/distutils/distutils.cfg
+[easy_install]
+allow-hosts = None
+EOF
+  '';
+}