Virtualenv cell magic

IPython/extensions/tests/test_virtualenvmagic.py

@@ -0,0 +1,64 @@
+# -*- coding: utf-8 -*-
+"""
+Tests for the virtualenvmagic extension
+Author: Flávio Codeço Coelho - @fccoelho
+"""
+
+import nose.tools as nt
+import os, shutil
+from nose import SkipTest
+import virtualenv
+from IPython.utils.tempdir import TemporaryDirectory
+
+home_dir = os.getenv('HOME')
+user_venv_dir = os.path.join(home_dir,'Envs/') if not "WORKON_HOME" \
+    in os.environ else os.getenv("WORKON_HOME")
+if not os.path.exists(os.path.join(home_dir,'Envs/')):
+    os.mkdir(os.path.join(home_dir,'Envs/'))
+
+global testenv_dir
+
+
+
+def setup():
+    global testenv_dir
+    ip = get_ipython()
+    #creating a testing virtualenv
+    testenv_dir = TemporaryDirectory()
+    os.environ['WORKON_HOME'] = testenv_dir.name
+    virtualenv.create_environment(os.path.join(testenv_dir.name,'testenv'))
+    ip.extension_manager.load_extension('virtualenvmagic')
+
+def teardown():
+    del os.environ['WORKON_HOME']
+    testenv_dir.cleanup()
+
+
+
+def test_virtualenv_testenv():
+    ip = get_ipython()
+    result = ip.run_cell_magic('virtualenv', 'testenv', 'import sys;print(sys.path)')
+    nt.assert_equals('tmp', os.path.split(eval(result)[1])[0].split(os.path.sep)[1])
+
+def test_virtualenv_nonexisting():
+    ip = get_ipython()
+    result = ip.run_cell_magic('virtualenv', 'nonexistingenv', 'print("hello")')
+    nt.assert_equals(None, result)
+
+def test_capturing_python_error():
+    ip = get_ipython()
+    result = ip.run_cell_magic('virtualenv', 'testenv', 'print(x)')
+    # traceback is sent to stderror
+    nt.assert_equals("",result)
+
+@nt.nottest
+def env_exists(env):
+    """
+    check if environment exists
+    """
+    if 'WORKON_HOME' not in os.environ:
+        return False
+    if os.path.exists(os.path.join(os.environ['WORKON_HOME'], env)):
+        return True
+    else:
+        return False

IPython/extensions/virtualenvmagic.py

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+# -*- coding: utf-8 -*-
+"""
+Virtualenv magic
+Requires virtualenv and virtualenv Wrapper
+Author: Flávio Codeço Coelho - @fccoelho
+Thanks to @turicas for helpful tips
+"""
+import sys
+import os
+import shlex
+from subprocess import Popen, PIPE
+from IPython.core.magic import cell_magic
+
+
+@cell_magic('virtualenv')
+def virtualenv(line, cell):
+    """
+    This magic enables the execution of code in a cell on a
+    pre-existing virtual env. It Requires Virtualenv and VirtualenvWrapper
+    to be installed in the system.
+    The virtual env to be used must be created in advance.
+
+    Usage
+    =====
+    To activate this magic just write at the top of the cell:
+
+        %%virtualenv my_env
+        import sys
+        print sys.version
+
+
+    """
+    if not os.path.exists(os.path.join(os.environ['WORKON_HOME'], line)):
+        print >> sys.stderr, "Environment {0} does not exist.".format(line)
+        return
+    cmd = get_activate_cmd(line)
+    p = Popen(cmd, stdout=PIPE, stderr=PIPE, stdin=PIPE)
+    out, err = p.communicate(cell)
+    if err:
+        print >> sys.stderr, err
+    return out
+
+_loaded = False
+
+def get_activate_cmd(line):
+    """
+    Returns the correct activate command given the platform
+    """
+    if sys.platform.startswith("win"):
+        env_activate_cmd = os.path.join(os.environ['WORKON_HOME'],line,
+        'Scripts','activate') + "; python -"
+    else:
+        env_activate_cmd = 'bash -c "source {0}/{1}/bin/activate && python -"'\
+    .format(os.environ['WORKON_HOME'], line)
+
+    cmd = shlex.split(env_activate_cmd)
+    return cmd
+
+
+def load_ipython_extension(ip):
+    """
+    Load the extension in IPython.
+    """
+    global _loaded
+    if not _loaded:
+        if 'WORKON_HOME' in os.environ:
+            ip.register_magic_function(virtualenv, 'cell')
+            _loaded = True
+        else:
+            print >> sys.stderr, "You must have Virtualenv and \
+            VirtualenvWrapper installed."