Dynamically import modules of extensions

CHANGELOG.rst

@@ -7,6 +7,12 @@ Change log
 Added
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+#. `#90 <https://github.com/moremoban/moban/issues/90>`_: Dynamically import
+   modules of extensions in order to support third-party extensions
+
+Added
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 #. `#165 <https://github.com/moremoban/moban/issues/165>`_: Copy as plugins
 
 Added

moban/jinja2/engine.py

@@ -1,3 +1,5 @@
+from importlib import import_module
+
 from jinja2 import Template, Environment, FileSystemLoader
 from lml.loader import scan_plugins_regex
 from lml.plugin import PluginInfo, PluginManager
@@ -74,6 +76,7 @@ def __init__(self, template_dirs, extensions=None):
         if is_extension_list_valid(extensions):
             # because it is modified here
             env_params["extensions"] += extensions
+        import_module_of_extension(extensions)
         self.jj2_environment = Environment(**env_params)
         for filter_name, filter_function in FILTERS.get_all():
             self.jj2_environment.filters[filter_name] = filter_function
@@ -136,3 +139,12 @@ def is_extension_list_valid(extensions):
         and isinstance(extensions, list)
         and len(extensions) > 0
     )
+
+
+def import_module_of_extension(extensions):
+    modules = set()
+    if extensions:
+        for extension in extensions:
+            modules.add(extension.split('.')[0])
+    for module in modules:
+        import_module(module)

tests/requirements.txt

@@ -8,4 +8,4 @@ black;python_version>="3.6"
 isort;python_version>="3.6"
 moban-handlebars
 pypi-mobans-pkg
-
+jinja2_time

tests/test_engine.py

@@ -1,3 +1,4 @@
+import sys
 import os
 
 from mock import patch
@@ -6,7 +7,11 @@
 
 import moban.exceptions as exceptions
 from moban.plugins import ENGINES
-from moban.jinja2.engine import Engine, is_extension_list_valid
+from moban.jinja2.engine import (
+    Engine,
+    is_extension_list_valid,
+    import_module_of_extension,
+)
 from moban.plugins.context import Context
 from moban.plugins.template import TemplateEngine, expand_template_directories
 
@@ -137,3 +142,15 @@ def test_extensions_validator():
         actual.append(is_extension_list_valid(fixture))
 
     eq_(expected, actual)
+
+
+def test_import():
+    extensions = [
+        "jinja2.ext.do",
+        "jinja2_time.TimeExtension",
+        "jinja2.ext.loopcontrols",
+    ]
+    import_module_of_extension(extensions)
+    modules = ["jinja2", "jinja2_time"]
+    for module in modules:
+        assert module in sys.modules