Allow use of existing virtualenv

- Allow user to specify a virtualenv to use instead of building one, fixes #26.
- Add test to be sure a supplied virtualenv is used

Author: martinb3

README.md

@@ -47,6 +47,11 @@ To specify an alternative profile that has been defined in `~/.aws/credentials`
 lambda-uploader --profile=alternative-profile
 ```
 
+To specify an alternative, prexisting virtualenv use the `--virtualenv` parameter.
+```shell
+lambda-uploader --virtualenv=~/.virtualenv/my_custom_virtualenv
+```
+
 If you would prefer to upload another way you can tell the uploader to ignore the upload.
 This will create a package and leave it in the project directory.
 ```shell

README.rst

@@ -63,6 +63,12 @@ To specify an alternative profile that has been defined in
 
     lambda-uploader --profile=alternative-profile
 
+To specify an alternative, prexisting virtualenv use the ``--virtualenv`` parameter.
+
+.. code:: shell
+
+    lambda-uploader --virtualenv=~/.virtualenv/my_custom_virtualenv
+
 If you would prefer to upload another way you can tell the uploader to
 ignore the upload. This will create a package and leave it in the
 project directory.

lambda_uploader/package.py

@@ -26,28 +26,38 @@
 ZIPFILE_NAME = 'lambda_function.zip'
 
 
-def build_package(path, requirements):
-    pkg = Package(path)
+def build_package(path, requirements, virtualenv=None):
+    pkg = Package(path, virtualenv)
 
     pkg.clean_workspace()
     pkg.clean_zipfile()
     pkg.prepare_workspace()
-    pkg.install_requirements(requirements)
+    if virtualenv:
+        if not os.path.isdir(virtualenv):
+            raise Exception("supplied virtualenv %s not found" % virtualenv)
+        LOG.info("Using existing virtualenv found in %s" % virtualenv)
+    else:
+        LOG.info('Building new virtualenv and installing requirements')
+        pkg.prepare_virtualenv()
+        pkg.install_requirements(requirements)
     pkg.package()
     return pkg
 
 
 class Package(object):
-    def __init__(self, path):
+    def __init__(self, path, virtualenv=None):
         self._path = path
         self._temp_workspace = os.path.join(path,
                                             TEMP_WORKSPACE_NAME)
         self.zip_file = os.path.join(path, ZIPFILE_NAME)
 
-        self._pkg_venv = os.path.join(self._temp_workspace, 'venv')
-        self._venv_pip = 'bin/pip'
-        if sys.platform == 'win32' or sys.platform == 'cygwin':
-            self._venv_pip = 'Scripts\pip.exe'
+        if virtualenv:
+            self._pkg_venv = virtualenv
+        else:
+            self._pkg_venv = os.path.join(self._temp_workspace, 'venv')
+            self._venv_pip = 'bin/pip'
+            if sys.platform == 'win32' or sys.platform == 'cygwin':
+                self._venv_pip = 'Scripts\pip.exe'
 
     def clean_workspace(self):
         if os.path.isdir(self._temp_workspace):
@@ -61,6 +71,7 @@ def prepare_workspace(self):
         # Setup temporary workspace
         os.mkdir(self._temp_workspace)
 
+    def prepare_virtualenv(self):
         proc = Popen(["virtualenv", self._pkg_venv], stdout=PIPE, stderr=PIPE)
         stdout, stderr = proc.communicate()
         LOG.debug("Virtualenv stdout: %s" % stdout)

lambda_uploader/shell.py

@@ -50,7 +50,7 @@ def _execute(args):
     cfg = config.Config(pth, args.config, role=args.role)
 
     _print('Building Package')
-    pkg = package.build_package(pth, cfg.requirements)
+    pkg = package.build_package(pth, cfg.requirements, args.virtualenv)
 
     if not args.no_clean:
         pkg.clean_workspace()
@@ -97,6 +97,9 @@ def main(arv=None):
                         action='store_const',
                         help='publish an upload to an immutable version',
                         const=True)
+    parser.add_argument('--virtualenv', '-e',
+                        help='use specified virtualenv instead of making one',
+                        default=None)
     parser.add_argument('--role', dest='role',
                         default=getenv('LAMBDA_UPLOADER_ROLE'),
                         help=('IAM role to assign the lambda function, '

test/test_package.py

@@ -39,6 +39,7 @@ def test_prepare_workspace():
 
     pkg = package.Package(TESTING_TEMP_DIR)
     pkg.prepare_workspace()
+    pkg.prepare_virtualenv()
     assert path.isdir(temp_workspace)
     assert path.isdir(path.join(temp_workspace, 'venv'))
     if sys.platform == 'win32' or sys.platform == 'cygwin':
@@ -63,6 +64,11 @@ def test_install_requirements():
     assert path.isdir(path.join(site_packages, '_pytest'))
 
 
+def test_existing_virtualenv():
+    pkg = package.Package(TESTING_TEMP_DIR, 'abc')
+    assert pkg._pkg_venv == 'abc'
+
+
 def test_package():
     pkg = package.Package(TESTING_TEMP_DIR)
     pkg.package()