Make mako template lookups pluggable.

This code adds the ability to add Mako template lookup directories on
the fly, allowing third party add-ons to contribute their own Mako templates.
A new API function for registering Mako templates is introduced::

    from edxmako import add_lookup

    add_lookup('main', '/path/to/templates')

    # Or, specify a package to lookup using pkg_resources.  This will
    # add the 'templates' directory inside the current package:
    add_lookup('main', 'templates', package=__name__)

common/djangoapps/edxmako/__init__.py

@@ -11,5 +11,6 @@
 #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #   See the License for the specific language governing permissions and
 #   limitations under the License.
+LOOKUP = {}
 
-lookup = None
+from .paths import add_lookup, lookup_template

common/djangoapps/edxmako/paths.py

+"""
+Set up lookup paths for mako templates.
+"""
+import os
+import pkg_resources
+
+from django.conf import settings
+from mako.lookup import TemplateLookup
+
+from . import LOOKUP
+
+
+class DynamicTemplateLookup(TemplateLookup):
+    """
+    A specialization of the standard mako `TemplateLookup` class which allows
+    for adding directories progressively.
+    """
+    def add_directory(self, directory):
+        """
+        Add a new directory to the template lookup path.
+        """
+        self.directories.append(os.path.normpath(directory))
+
+
+def add_lookup(namespace, directory, package=None):
+    """
+    Adds a new mako template lookup directory to the given namespace.
+
+    If `package` is specified, `pkg_resources` is used to look up the directory
+    inside the given package.  Otherwise `directory` is assumed to be a path
+    in the filesystem.
+    """
+    templates = LOOKUP.get(namespace)
+    if not templates:
+        LOOKUP[namespace] = templates = DynamicTemplateLookup(
+            module_directory=settings.MAKO_MODULE_DIR,
+            output_encoding='utf-8',
+            input_encoding='utf-8',
+            default_filters=['decode.utf8'],
+            encoding_errors='replace',
+        )
+    if package:
+        directory = pkg_resources.resource_filename(package, directory)
+    templates.add_directory(directory)
+
+
+def lookup_template(namespace, name):
+    """
+    Look up a Mako template by namespace and name.
+    """
+    return LOOKUP[namespace].get_template(name)

common/djangoapps/edxmako/shortcuts.py

@@ -18,7 +18,7 @@ import logging
 
 from microsite_configuration.middleware import MicrositeConfiguration
 
-import edxmako
+from edxmako import lookup_template
 import edxmako.middleware
 from django.conf import settings
 from django.core.urlresolvers import reverse
@@ -100,7 +100,7 @@ def render_to_string(template_name, dictionary, context=None, namespace='main'):
     if context:
         context_dictionary.update(context)
     # fetch and render template
-    template = edxmako.lookup[namespace].get_template(template_name)
+    template = lookup_template(namespace, template_name)
     return template.render_unicode(**context_dictionary)
 
 

common/djangoapps/edxmako/startup.py

 """
 Initialize the mako template lookup
 """
-
-import tempdir
 from django.conf import settings
-from mako.lookup import TemplateLookup
-
-import edxmako
+from . import add_lookup
 
 
 def run():
-    """Setup mako variables and lookup object"""
-    # Set all mako variables based on django settings
+    """
+    Setup mako lookup directories.
+    """
     template_locations = settings.MAKO_TEMPLATES
-    module_directory = getattr(settings, 'MAKO_MODULE_DIR', None)
-
-    if module_directory is None:
-        module_directory = tempdir.mkdtemp_clean()
-
-    lookup = {}
-
-    for location in template_locations:
-        lookup[location] = TemplateLookup(
-            directories=template_locations[location],
-            module_directory=module_directory,
-            output_encoding='utf-8',
-            input_encoding='utf-8',
-            default_filters=['decode.utf8'],
-            encoding_errors='replace',
-        )
-
-    edxmako.lookup = lookup
+    for namespace, directories in template_locations.items():
+        for directory in directories:
+            add_lookup(namespace, directory)

common/djangoapps/edxmako/template.py

@@ -19,7 +19,7 @@ from edxmako.shortcuts import marketing_link
 import edxmako
 import edxmako.middleware
 
-django_variables = ['lookup', 'output_encoding', 'encoding_errors']
+DJANGO_VARIABLES = ['output_encoding', 'encoding_errors']
 
 # TODO: We should make this a Django Template subclass that simply has the MakoTemplate inside of it? (Intead of inheriting from MakoTemplate)
 
@@ -34,8 +34,8 @@ class Template(MakoTemplate):
     def __init__(self, *args, **kwargs):
         """Overrides base __init__ to provide django variable overrides"""
         if not kwargs.get('no_django', False):
-            overrides = dict([(k, getattr(edxmako, k, None),) for k in django_variables])
-            overrides['lookup'] = overrides['lookup']['main']
+            overrides = {k: getattr(edxmako, k, None) for k in DJANGO_VARIABLES}
+            overrides['lookup'] = edxmako.LOOKUP['main']
             kwargs.update(overrides)
         super(Template, self).__init__(*args, **kwargs)
 

common/djangoapps/edxmako/tests.py

 from django.test import TestCase
 from django.test.utils import override_settings
 from django.core.urlresolvers import reverse
+from edxmako import add_lookup, LOOKUP
 from edxmako.shortcuts import marketing_link
 from mock import patch
 from util.testing import UrlResetMixin
@@ -24,3 +25,15 @@ class ShortcutsTests(UrlResetMixin, TestCase):
             expected_link = reverse('login')
             link = marketing_link('ABOUT')
             self.assertEquals(link, expected_link)
+
+
+class AddLookupTests(TestCase):
+    """
+    Test the `add_lookup` function.
+    """
+    @patch('edxmako.LOOKUP', {})
+    def test_with_package(self):
+        add_lookup('test', 'management', __name__)
+        dirs = LOOKUP['test'].directories
+        self.assertEqual(len(dirs), 1)
+        self.assertTrue(dirs[0].endswith('management'))

common/djangoapps/student/management/commands/massemail.py

 from django.core.management.base import BaseCommand
 from django.contrib.auth.models import User
 
-import edxmako
+from edxmako import lookup_template
 
 
 class Command(BaseCommand):
@@ -15,8 +15,8 @@ body, and an _subject.txt for the subject. '''
         #text = open(args[0]).read()
         #subject = open(args[1]).read()
         users = User.objects.all()
-        text = edxmako.lookup['main'].get_template('email/' + args[0] + ".txt").render()
-        subject = edxmako.lookup['main'].get_template('email/' + args[0] + "_subject.txt").render().strip()
+        text = lookup_template('main', 'email/' + args[0] + ".txt").render()
+        subject = lookup_template('main', 'email/' + args[0] + "_subject.txt").render().strip()
         for user in users:
             if user.is_active:
                 user.email_user(subject, text)

common/djangoapps/student/management/commands/massemailtxt.py

@@ -4,7 +4,7 @@ import time
 from django.core.management.base import BaseCommand
 from django.conf import settings
 
-import edxmako
+from edxmako import lookup_template
 
 from django.core.mail import send_mass_mail
 import sys
@@ -39,8 +39,8 @@ rate -- messages per second
 
         users = [u.strip() for u in open(user_file).readlines()]
 
-        message = edxmako.lookup['main'].get_template('emails/' + message_base + "_body.txt").render()
-        subject = edxmako.lookup['main'].get_template('emails/' + message_base + "_subject.txt").render().strip()
+        message = lookup_template('main', 'emails/' + message_base + "_body.txt").render()
+        subject = lookup_template('main', 'emails/' + message_base + "_subject.txt").render().strip()
         rate = int(ratestr)
 
         self.log_file = open(logfilename, "a+", buffering=0)

common/djangoapps/student/tests/email/test.txt

+Test body.

common/djangoapps/student/tests/email/test_subject.txt

+Test subject.

common/djangoapps/student/tests/emails/test_body.txt

+Test body.

common/djangoapps/student/tests/emails/test_subject.txt

+Test subject.

common/djangoapps/student/tests/test_massemail.py

+"""
+Test `massemail` and `massemailtxt` commands.
+"""
+import mock
+import pkg_resources
+
+from django.core import mail
+from django.test import TestCase
+
+from edxmako import add_lookup
+from ..management.commands import massemail
+from ..management.commands import massemailtxt
+
+
+class TestMassEmailCommands(TestCase):
+    """
+    Test `massemail` and `massemailtxt` commands.
+    """
+
+    @mock.patch('edxmako.LOOKUP', {})
+    def test_massemailtxt(self):
+        """
+        Test the `massemailtext` command.
+        """
+        add_lookup('main', '', package=__name__)
+        userfile = pkg_resources.resource_filename(__name__, 'test_massemail_users.txt')
+        command = massemailtxt.Command()
+        command.handle(userfile, 'test', '/dev/null', 10)
+        self.assertEqual(len(mail.outbox), 2)
+        self.assertEqual(mail.outbox[0].to, ["Fred"])
+        self.assertEqual(mail.outbox[0].subject, "Test subject.")
+        self.assertEqual(mail.outbox[0].body.strip(), "Test body.")
+        self.assertEqual(mail.outbox[1].to, ["Barney"])
+        self.assertEqual(mail.outbox[1].subject, "Test subject.")
+        self.assertEqual(mail.outbox[1].body.strip(), "Test body.")
+
+    @mock.patch('edxmako.LOOKUP', {})
+    @mock.patch('student.management.commands.massemail.User')
+    def test_massemail(self, usercls):
+        """
+        Test the `massemail` command.
+        """
+        add_lookup('main', '', package=__name__)
+        fred = mock.Mock()
+        barney = mock.Mock()
+        usercls.objects.all.return_value = [fred, barney]
+        command = massemail.Command()
+        command.handle('test')
+        fred.email_user.assert_called_once_with('Test subject.', 'Test body.\n')
+        barney.email_user.assert_called_once_with('Test subject.', 'Test body.\n')

common/djangoapps/student/tests/test_massemail_users.txt

+Fred
+Barney

lms/djangoapps/django_comment_client/tests/test.mustache

+Testing 1 2 3.

lms/djangoapps/django_comment_client/tests/test_utils.py

 import json
+import mock
 from datetime import datetime
 from pytz import UTC
 from django.core.urlresolvers import reverse
@@ -11,6 +12,7 @@ import django_comment_client.utils as utils
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from edxmako import add_lookup
 
 
 class DictionaryTestCase(TestCase):
@@ -505,3 +507,17 @@ class JsonResponseTestCase(TestCase, UnicodeTestMixin):
         response = utils.JsonResponse(text)
         reparsed = json.loads(response.content)
         self.assertEqual(reparsed, text)
+
+
+class RenderMustacheTests(TestCase):
+    """
+    Test the `render_mustache` utility function.
+    """
+
+    @mock.patch('edxmako.LOOKUP', {})
+    def test_it(self):
+        """
+        Basic test.
+        """
+        add_lookup('main', '', package=__name__)
+        self.assertEqual(utils.render_mustache('test.mustache', {}), 'Testing 1 2 3.\n')

lms/djangoapps/django_comment_client/utils.py

 import pytz
 from collections import defaultdict
 import logging
-import urllib
 from datetime import datetime
 
 from django.contrib.auth.models import User
@@ -12,7 +11,7 @@ from django.utils import simplejson
 from django_comment_common.models import Role, FORUM_ROLE_STUDENT
 from django_comment_client.permissions import check_permissions_by_view
 
-import edxmako
+from edxmako import lookup_template
 import pystache_custom as pystache
 
 from xmodule.modulestore.django import modulestore
@@ -307,7 +306,7 @@ def get_metadata_for_threads(course_id, threads, user, user_info):
 
 
 def render_mustache(template_name, dictionary, *args, **kwargs):
-    template = edxmako.lookup['main'].get_template(template_name).source
+    template = lookup_template('main', template_name).source
     return pystache.render(template, dictionary)