apache: Implement diagnostic test for web server component

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

doc/dev/tutorial/components.rst

@@ -57,14 +57,18 @@ app. Let us do that in our app's class.
       def __init__(self):
         ...
 
-        webserver = Webserver('webserver-transmission', 'transmission-plinth')
+        webserver = Webserver('webserver-transmission', 'transmission-plinth'
+                              urls=['https://{host}/transmission'])
         self.add(webserver)
 
 The first argument to instantiate the
 :class:`~plinth.modules.apache.components.Webserver` class is a unique ID. The
 second is the name of the Apache2 web server configuration snippet that contains
 the directives to proxy Transmission web interface via Apache2. We then need to
-create the configuration file itself in ``tranmission-freedombox.conf``.
+create the configuration file itself in ``tranmission-freedombox.conf``. The
+final argument is the list of URLs that the app exposes to the users of the app.
+This information is used to check if the URLs are accessible as expected when
+the user requests diagnostic tests on the app.
 
 .. code-block:: apache
 

plinth/modules/apache/components.py

@@ -23,7 +23,7 @@ from plinth import action_utils, actions, app
 
 class Webserver(app.LeaderComponent):
     """Component to enable/disable Apache configuration."""
-    def __init__(self, component_id, web_name, kind='config'):
+    def __init__(self, component_id, web_name, kind='config', urls=None):
         """Initialize the web server component.
 
         component_id should be a unique ID across all components of an app and
@@ -37,11 +37,15 @@ class Webserver(app.LeaderComponent):
         'module' for configuration in /etc/apache2/mods-available/, 'site' for
         configuration in /etc/apache2/sites-available/.
 
+        urls is a list of URLs over which a HTTP services will be available due
+        to this component. This list is only used for running diagnostics.
+
         """
         super().__init__(component_id)
 
         self.web_name = web_name
         self.kind = kind
+        self.urls = urls or []
 
     def is_enabled(self):
         """Return whether the Apache configuration is enabled."""
@@ -58,6 +62,24 @@ class Webserver(app.LeaderComponent):
             'apache',
             ['disable', '--name', self.web_name, '--kind', self.kind])
 
+    def diagnose(self):
+        """Check if the web path is accessible by clients.
+
+        See :py:meth:`plinth.app.Component.diagnose`.
+
+        """
+        results = []
+        for url in self.urls:
+            if '{host}' in url:
+                results.extend(
+                    action_utils.diagnose_url_on_all(url,
+                                                     check_certificate=False))
+            else:
+                results.append(
+                    action_utils.diagnose_url(url, check_certificate=False))
+
+        return results
+
 
 class Uwsgi(app.LeaderComponent):
     """Component to enable/disable uWSGI configuration."""

plinth/modules/apache/tests/test_components.py

@@ -30,13 +30,16 @@ def test_webserver_init():
     with pytest.raises(ValueError):
         Webserver(None, None)
 
-    webserver = Webserver('test-webserver', 'test-config', kind='module')
+    webserver = Webserver('test-webserver', 'test-config', kind='module',
+                          urls=['url1', 'url2'])
     assert webserver.component_id == 'test-webserver'
     assert webserver.web_name == 'test-config'
     assert webserver.kind == 'module'
+    assert webserver.urls == ['url1', 'url2']
 
     webserver = Webserver('test-webserver', None)
     assert webserver.kind == 'config'
+    assert webserver.urls == []
 
 
 @patch('plinth.action_utils.webserver_is_enabled')
@@ -77,6 +80,28 @@ def test_webserver_disable(superuser_run):
     ])
 
 
+@patch('plinth.action_utils.diagnose_url')
+@patch('plinth.action_utils.diagnose_url_on_all')
+def test_webserver_diagnose(diagnose_url_on_all, diagnose_url):
+    """Test running diagnostics."""
+    def on_all_side_effect(url, check_certificate):
+        return [('test-result-' + url, 'success')]
+
+    def side_effect(url, check_certificate):
+        return ('test-result-' + url, 'success')
+
+    diagnose_url_on_all.side_effect = on_all_side_effect
+    diagnose_url.side_effect = side_effect
+    webserver = Webserver('test-webserver', 'test-config',
+                          urls=['{host}url1', 'url2'])
+    results = webserver.diagnose()
+    assert results == [('test-result-{host}url1', 'success'),
+                       ('test-result-url2', 'success')]
+    diagnose_url_on_all.assert_has_calls(
+        [call('{host}url1', check_certificate=False)])
+    diagnose_url.assert_has_calls([call('url2', check_certificate=False)])
+
+
 def test_uwsgi_init():
     """Test that uWSGI component can be initialized."""
     with pytest.raises(ValueError):