Allow using several custom template directories

changelog.d/10587.misc

@@ -0,0 +1 @@
+Allow multiple custom directories in `read_templates`.

synapse/config/_base.py

@@ -237,7 +237,7 @@ def read_template(self, filename: str) -> jinja2.Template:
     def read_templates(
         self,
         filenames: List[str],
-        custom_template_directory: Optional[str] = None,
+        custom_template_directories: Optional[List[Optional[str]]] = None,
     ) -> List[jinja2.Template]:
         """Load a list of template files from disk using the given variables.
 
@@ -251,8 +251,8 @@ def read_templates(
         Args:
             filenames: A list of template filenames to read.
 
-            custom_template_directory: A directory to try to look for the templates
-                before using the default Synapse template directory instead.
+            custom_template_directories: A list of directory to try to look for the
+                templates before using the default Synapse template directory instead.
 
         Raises:
             ConfigError: if the file's path is incorrect or otherwise cannot be read.
@@ -262,18 +262,23 @@ def read_templates(
         """
         search_directories = [self.default_template_dir]
 
-        # The loader will first look in the custom template directory (if specified) for the
-        # given filename. If it doesn't find it, it will use the default template dir instead
-        if custom_template_directory:
-            # Check that the given template directory exists
-            if not self.path_exists(custom_template_directory):
-                raise ConfigError(
-                    "Configured template directory does not exist: %s"
-                    % (custom_template_directory,)
-                )
+        # The loader will first look in the custom template directories (if specified)
+        # for the given filename. If it doesn't find it, it will use the default
+        # template dir instead.
+        if custom_template_directories is not None:
+            for custom_template_directory in custom_template_directories:
+                # Elements in the list might be None if they were retrieved from the
+                # configuration dict using config_dict.get(...).
+                if custom_template_directory:
+                    # Check that the given template directory exists
+                    if not self.path_exists(custom_template_directory):
+                        raise ConfigError(
+                            "Configured template directory does not exist: %s"
+                            % (custom_template_directory,)
+                        )
 
-            # Search the custom template directory as well
-            search_directories.insert(0, custom_template_directory)
+                    # Search the custom template directory as well
+                    search_directories.insert(0, custom_template_directory)
 
         # TODO: switch to synapse.util.templates.build_jinja_env
         loader = jinja2.FileSystemLoader(search_directories)

synapse/config/account_validity.py

@@ -88,5 +88,5 @@ def read_config(self, config, **kwargs):
                 "account_previously_renewed.html",
                 invalid_token_template_filename,
             ],
-            account_validity_template_dir,
+            [account_validity_template_dir],
         )

synapse/config/emailconfig.py

@@ -257,7 +257,7 @@ def read_config(self, config, **kwargs):
                     registration_template_success_html,
                     add_threepid_template_success_html,
                 ],
-                template_dir,
+                [template_dir],
             )
 
             # Render templates that do not contain any placeholders
@@ -297,7 +297,7 @@ def read_config(self, config, **kwargs):
                 self.email_notif_template_text,
             ) = self.read_templates(
                 [notif_template_html, notif_template_text],
-                template_dir,
+                [template_dir],
             )
 
             self.email_notif_for_new_users = email_config.get(
@@ -320,7 +320,7 @@ def read_config(self, config, **kwargs):
                 self.account_validity_template_text,
             ) = self.read_templates(
                 [expiry_template_html, expiry_template_text],
-                template_dir,
+                [template_dir],
             )
 
         subjects_config = email_config.get("subjects", {})

synapse/config/sso.py

@@ -63,7 +63,7 @@ def read_config(self, config, **kwargs):
                 "sso_auth_success.html",
                 "sso_auth_bad_user.html",
             ],
-            self.sso_template_dir,
+            [self.sso_template_dir],
         )
 
         # These templates have no placeholders, so render them here

synapse/module_api/__init__.py

@@ -677,7 +677,7 @@ def read_templates(
             A list containing the loaded templates, with the orders matching the one of
             the filenames parameter.
         """
-        return self._hs.config.read_templates(filenames, custom_template_directory)
+        return self._hs.config.read_templates(filenames, [custom_template_directory])
 
 
 class PublicRoomListManager:

tests/config/test_base.py

@@ -30,7 +30,7 @@ def test_loading_missing_templates(self):
         # contain template files
         with tempfile.TemporaryDirectory() as tmp_dir:
             # Attempt to load an HTML template from our custom template directory
-            template = self.hs.config.read_templates(["sso_error.html"], tmp_dir)[0]
+            template = self.hs.config.read_templates(["sso_error.html"], [tmp_dir])[0]
 
         # If no errors, we should've gotten the default template instead
 
@@ -60,7 +60,7 @@ def test_loading_custom_templates(self):
 
                 # Attempt to load the template from our custom template directory
                 template = (
-                    self.hs.config.read_templates([template_filename], tmp_dir)
+                    self.hs.config.read_templates([template_filename], [tmp_dir])
                 )[0]
 
         # Render the template
@@ -77,5 +77,5 @@ def test_loading_custom_templates(self):
     def test_loading_template_from_nonexistent_custom_directory(self):
         with self.assertRaises(ConfigError):
             self.hs.config.read_templates(
-                ["some_filename.html"], "a_nonexistent_directory"
+                ["some_filename.html"], ["a_nonexistent_directory"]
             )