Simplifying the source_registry

caravel/__init__.py

@@ -14,7 +14,7 @@
 from flask_appbuilder.baseviews import expose
 from flask_cache import Cache
 from flask_migrate import Migrate
-from caravel import source_registry
+from caravel.source_registry import SourceRegistry
 from werkzeug.contrib.fixers import ProxyFix
 
 
@@ -96,7 +96,11 @@ def index(self):
 
 sm = appbuilder.sm
 
-src_registry = source_registry.SourceRegistry()
-
 get_session = appbuilder.get_session
+
+# Registering sources
+module_datasource_map = app.config.get("DEFAULT_MODULE_DS_MAP")
+module_datasource_map.update(app.config.get("ADDITIONAL_MODULE_DS_MAP"))
+SourceRegistry.register_sources(module_datasource_map)
+
 from caravel import views, config  # noqa

caravel/bin/caravel

@@ -20,14 +20,6 @@ config = app.config
 
 manager = Manager(app)
 manager.add_command('db', MigrateCommand)
-module_datasource_map = config.get("DEFAULT_MODULE_DS_MAP")
-module_datasource_map.update(config.get("ADDITIONAL_MODULE_DS_MAP"))
-
-datasources = {}
-for module in module_datasource_map:
-    datasources[module] = __import__(module, fromlist=module_datasource_map[module])
-
-utils.register_sources(datasources, module_datasource_map, caravel.src_registry)
 
 
 @manager.option(

caravel/models.py

@@ -26,7 +26,6 @@
 from flask_appbuilder import Model
 from flask_appbuilder.models.mixins import AuditMixin
 from flask_appbuilder.models.decorators import renders
-from flask_appbuilder.security.sqla.models import Role, PermissionView
 from flask_babel import lazy_gettext as _
 
 from pydruid.client import PyDruid
@@ -50,7 +49,8 @@
 from werkzeug.datastructures import ImmutableMultiDict
 
 import caravel
-from caravel import app, db, get_session, utils, sm, src_registry
+from caravel import app, db, get_session, utils, sm
+from caravel.source_registry import SourceRegistry
 from caravel.viz import viz_types
 from caravel.utils import flasher, MetricPermException, DimSelector
 
@@ -172,7 +172,7 @@ def __repr__(self):
 
     @property
     def cls_model(self):
-        return src_registry.sources[self.datasource_type]
+        return SourceRegistry.sources[self.datasource_type]
 
     @property
     def datasource(self):
@@ -2028,7 +2028,7 @@ class DatasourceAccessRequest(Model, AuditMixinNullable):
 
     @property
     def cls_model(self):
-        return src_registry.sources[self.datasource_type]
+        return SourceRegistry.sources[self.datasource_type]
 
     @property
     def username(self):

caravel/source_registry.py

@@ -1,15 +1,14 @@
-from flask import flash
 
 
 class SourceRegistry(object):
     """ Central Registry for all available datasource engines"""
 
     sources = {}
 
-    def add_source(self, ds_type, cls_model):
-        if ds_type not in self.sources:
-            self.sources[ds_type] = cls_model
-        if self.sources[ds_type] is not cls_model:
-            raise Exception(
-                'source type: {} is already associated with Model: {}'.format(
-                    ds_type, self.sources[ds_type]))
+    @classmethod
+    def register_sources(cls, datasource_config):
+        for module_name, class_names in datasource_config.items():
+            module_obj = __import__(module_name, fromlist=class_names)
+            for class_name in class_names:
+                source_class = getattr(module_obj, class_name)
+                cls.sources[source_class.type] = source_class

caravel/utils.py

@@ -426,14 +426,6 @@ def readfile(filepath):
     return content
 
 
-def register_sources(datasources, module_datasource_map, registry):
-    for m in datasources:
-        datasource_list = module_datasource_map[m]
-        for ds in datasource_list:
-            ds_class = getattr(datasources[m], ds)
-            registry.add_source(ds_class.type, ds_class)
-
-
 def generic_find_constraint_name(table, columns, referenced, db):
     """Utility to find a constraint name in alembic migrations"""
     t = sa.Table(table, db.metadata, autoload=True, autoload_with=db.engine)

caravel/views.py

@@ -34,8 +34,9 @@
 import caravel
 from caravel import (
     appbuilder, cache, db, models, viz, utils, app,
-    sm, ascii_art, sql_lab, src_registry
+    sm, ascii_art, sql_lab
 )
+from caravel.source_registry import SourceRegistry
 from caravel.models import DatasourceAccessRequest as DAR
 
 config = app.config
@@ -748,9 +749,9 @@ def add(self):
         if not widget:
             return redirect(self.get_redirect())
 
-        sources = src_registry.sources
+        sources = SourceRegistry.sources
         for source in sources:
-            ds = db.session.query(src_registry.sources[source]).first()
+            ds = db.session.query(SourceRegistry.sources[source]).first()
             if ds is not None:
                 url = "/{}/list/".format(ds.baselink)
                 msg = _("Click on a {} link to create a Slice".format(source))
@@ -1054,7 +1055,7 @@ def approve(self):
         role_to_extend = request.args.get('role_to_extend')
 
         session = db.session
-        datasource_class = src_registry.sources[datasource_type]
+        datasource_class = SourceRegistry.sources[datasource_type]
         datasource = session.query(datasource_class).filter_by(
             id=datasource_id).first()
 
@@ -1117,7 +1118,7 @@ def approve(self):
     @log_this
     def explore(self, datasource_type, datasource_id, slice_id=None):
         error_redirect = '/slicemodelview/list/'
-        datasource_class = src_registry.sources[datasource_type]
+        datasource_class = SourceRegistry.sources[datasource_type]
         datasources = db.session.query(datasource_class).all()
         datasources = sorted(datasources, key=lambda ds: ds.full_name)
         datasource = [ds for ds in datasources if int(datasource_id) == ds.id]

tests/core_tests.py

@@ -17,7 +17,8 @@
 from flask_appbuilder.security.sqla import models as ab_models
 
 import caravel
-from caravel import app, db, models, utils, appbuilder, sm, src_registry
+from caravel import app, db, models, utils, appbuilder, sm
+from caravel.source_registry import SourceRegistry
 from caravel.models import DruidDatasource
 
 from .base_tests import CaravelTestCase
@@ -243,7 +244,7 @@ def test_approve(self):
         self.login('admin')
 
         def prepare_request(ds_type, ds_name, role):
-            ds_class = src_registry.sources[ds_type]
+            ds_class = SourceRegistry.sources[ds_type]
             # TODO: generalize datasource names
             if ds_type == 'table':
                 ds = session.query(ds_class).filter(