remove dependency on pip internals

closes #1438

dev-requirements.txt

@@ -1,2 +1,3 @@
 django-bower
 django-debug-toolbar
+packaging

modoboa/core/commands/deploy.py

@@ -22,13 +22,7 @@
 
 from modoboa.core.commands import Command
 from modoboa.lib.api_client import ModoAPIClient
-
-try:
-    import pip
-except ImportError:
-    sys.stderr.write("Error: pip is required to install extensions.\n")
-    sys.exit(2)
-
+from modoboa.lib.sysutils import exec_cmd
 
 DBCONN_TPL = """
     '{{ conn_name }}': {
@@ -226,9 +220,12 @@ def handle(self, parsed_args):
             extensions = [(extension, extension.replace("-", "_"))
                           for extension in extensions]
             if not parsed_args.dont_install_extensions:
-                pip_args = (
-                    ["install"] + [extension[0] for extension in extensions])
-                pip.main(pip_args)
+                cmd = (
+                    sys.executable +
+                    " -m pip install " +
+                    " ".join([extension[0] for extension in extensions])
+                )
+                exec_cmd(cmd, capture_output=False)
             extra_settings = self.find_extra_settings(extensions)
             extensions = [extension[1] for extension in extensions]
 

setup.py

@@ -13,21 +13,21 @@
 import io
 from os import path
 
-from pip.req import parse_requirements
+from packaging.requirements import Requirement
 from setuptools import find_packages, setup
 
 
 def get_requirements(requirements_file):
-    """Use pip to parse requirements file."""
+    """Parse requirements file."""
     requirements = []
     if path.isfile(requirements_file):
-        for req in parse_requirements(requirements_file, session="hack"):
-            # check markers, such as
-            #
-            #     rope_py3k    ; python_version >= '3.0'
-            #
-            if req.match_markers():
-                requirements.append(str(req.req))
+        with io.open(requirements_file, encoding="utf-8") as fp:
+            for line in fp:
+                if line.startswith("#") or line.strip() == "":
+                    continue
+                req = Requirement(line)
+                if req.marker is None or req.marker.evaluate():
+                    requirements.append('%s%s' % (req.name, req.specifier))
     return requirements
 
 

test-requirements.txt

@@ -5,3 +5,4 @@ testfixtures==4.7.0
 tox
 psycopg2-binary>=2.7.4
 mysqlclient>=1.3.3
+packaging