Remove READTHEDOCS specific code from aiida.manage.configuration

To compile the documentation, the code has to be imported which includes
the Django database models. Unfortunately, Django will raise here if it
has not been configured. Normally this is done through the backend which
will load the backend environment for the currently loaded AiiDA profile.
Since on readthedocs.org AiiDA is not installed and so there won't be a
configuration with a profile to load, the profile management code was
monkey patched to provide a dummy profile just for this purpose.

Instead of cluttering the main codebase for this one exception, we move
the responsibility to the documentation configuration itself. The
requirements boil down to the Django settings being called and an AiiDA
configuration and profile to be loaded. Since loading a profile with a
django backend and loading said backend, the former will be accomplished
automatically. This will now also allow building the documentation
locally even if the default profile is not using a Django backend
because the dummy documentation profile will simply be used. The function
`aiida.manage.configuration.load_documentation_profile` performs all the
required actions.

aiida/manage/configuration/__init__.py

@@ -9,8 +9,8 @@
 ###########################################################################
 # pylint: disable=undefined-variable,wildcard-import,global-statement,redefined-outer-name,cyclic-import
 """Modules related to the configuration of an AiiDA instance."""
-
 import warnings
+
 from aiida.common.warnings import AiidaDeprecationWarning
 from .config import *
 from .options import *
@@ -20,9 +20,6 @@
 PROFILE = None
 BACKEND_UUID = None  # This will be set to the UUID of the profile as soon as its corresponding backend is loaded
 
-# This is used (and should be set to true) for the correct compilation of the documentation on readthedocs
-IN_RT_DOC_MODE = False
-
 __all__ = (
     config.__all__ + options.__all__ + profile.__all__ +
     ('get_config', 'get_config_option', 'load_profile', 'reset_config')
@@ -64,14 +61,8 @@ def load_profile(profile=None):
     # Reconfigure the logging to make sure that profile specific logging configuration options are taken into account.
     # Note that we do not configure with `with_orm=True` because that will force the backend to be loaded. This should
     # instead be done lazily in `Manager._load_backend`.
-
     configure_logging()
 
-    if IN_RT_DOC_MODE:
-        # on readthedocs, already load backend  (no schema check since no DB)
-        from aiida.manage.manager import get_manager
-        get_manager()._load_backend(schema_check=False)  # pylint: disable=protected-access
-
     return PROFILE
 
 
@@ -159,31 +150,7 @@ def get_config(create=False):
     global CONFIG
 
     if not CONFIG:
-        if IN_RT_DOC_MODE:
-            # The following is a dummy config.json configuration that it is used for the
-            # proper compilation of the documentation on readthedocs.
-            from aiida.manage.external.postgres import DEFAULT_DBINFO
-            import tempfile
-            CONFIG = Config(
-                tempfile.mkstemp()[1], {
-                    'default_profile': 'default',
-                    'profiles': {
-                        'default': {
-                            'AIIDADB_ENGINE': 'postgresql_psycopg2',
-                            'AIIDADB_BACKEND': 'django',
-                            'AIIDADB_HOST': DEFAULT_DBINFO['host'],
-                            'AIIDADB_PORT': DEFAULT_DBINFO['port'],
-                            'AIIDADB_NAME': 'aiidadb',
-                            'AIIDADB_PASS': '123',
-                            'default_user_email': 'aiida@epfl.ch',
-                            'AIIDADB_REPOSITORY_URI': 'file:///tmp/repository',
-                            'AIIDADB_USER': 'aiida'
-                        }
-                    }
-                }
-            )
-        else:
-            CONFIG = load_config(create=create)
+        CONFIG = load_config(create=create)
 
         if CONFIG.get_option('warnings.showdeprecations'):
             # If the user does not want to get AiiDA deprecation warnings, we disable them - this can be achieved with::
@@ -230,3 +197,38 @@ def get_config_option(option_name):
         value = value_profile if value_profile else config.get_option(option_name)
 
     return value
+
+
+def load_documentation_profile():
+    """Load a dummy profile just for the purposes of being able to build the documentation.
+
+    The building of the documentation will require importing the `aiida` package and some code will try to access the
+    loaded configuration and profile, which if not done will except. On top of that, Django will raise an exception if
+    the database models are loaded before its settings are loaded. This also is taken care of by loading a Django
+    profile and loading the corresponding backend. Calling this function will perform all these requirements allowing
+    the documentation to be built without having to install and configure AiiDA nor having an actual database present.
+    """
+    import tempfile
+    from aiida.manage.manager import get_manager
+    from .config import Config
+    from .profile import Profile
+
+    global PROFILE
+    global CONFIG
+
+    with tempfile.NamedTemporaryFile() as handle:
+        profile_name = 'readthedocs'
+        profile = {
+            'AIIDADB_ENGINE': 'postgresql_psycopg2',
+            'AIIDADB_BACKEND': 'django',
+            'AIIDADB_PORT': 5432,
+            'AIIDADB_HOST': 'localhost',
+            'AIIDADB_NAME': 'aiidadb',
+            'AIIDADB_PASS': 'aiidadb',
+            'AIIDADB_USER': 'aiida',
+            'AIIDADB_REPOSITORY_URI': 'file:///dev/null',
+        }
+        config = {'default_profile': profile_name, 'profiles': {profile_name: profile}}
+        PROFILE = Profile(profile_name, profile, from_config=True)
+        CONFIG = Config(handle.name, config)
+        get_manager()._load_backend(schema_check=False)  # pylint: disable=protected-access

docs/source/conf.py

@@ -18,15 +18,24 @@
 #
 # All configuration values have a default; values that are commented out
 # serve to show the default.
-
 import os
 import sys
 
-# Following 3 lines avoid the need of importing load_dbenv() for compiling the documentation -> works also without verdi install
+# Add `aiida` to the path so it can be imported without installing it
 sys.path.append(os.path.join(os.path.split(__file__)[0], os.pardir, os.pardir))
 
 import aiida
-from aiida.manage import configuration
+from aiida.manage.configuration import load_documentation_profile
+
+# Load the dummy profile even if we are running locally, this way the documentation will succeed even if the current
+# default profile of the AiiDA installation does not use a Django backend.
+load_documentation_profile()
+
+# If we are not on READTHEDOCS load the Sphinx theme manually
+if not os.environ.get('READTHEDOCS', None):
+    import sphinx_rtd_theme
+    html_theme = 'sphinx_rtd_theme'
+    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
@@ -233,25 +242,6 @@
 # If false, no module index is generated.
 #latex_domain_indices = True
 
-# on_rtd is whether we are on readthedocs.org
-on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
-
-
-if on_rtd:
-    # Set the global variable to trigger shortcut behavior in `aiida.manage.configuration.load_config`
-    configuration.IN_RT_DOC_MODE = True
-else:
-    try:
-        import sphinx_rtd_theme
-        html_theme = 'sphinx_rtd_theme'
-        html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
-    except ImportError:  # No sphinx_rtd_theme installed
-        pass
-
-# load AiiDA profile
-configuration.load_profile()
-
-
 def run_apidoc(_):
     """Runs sphinx-apidoc when building the documentation.