Merge pull request #81 from ottogroup/feature/activate-web-service

Add 'activate' web service endpoint

docs/user/web-service.rst

@@ -186,8 +186,8 @@ some example output:
        "properties": {"active-model": "8", "db-version": "1.2"}
    }
 
-Fit and Update Model Cache
---------------------------
+Fit, Update Model Cache, and Activate
+-------------------------------------
 
 Palladium allows for periodic updates of the model by use of the
 :class:`palladium.persistence.CachedUpdatePersister`.  For this to
@@ -283,3 +283,10 @@ endpoints is this:
             'methods': ['POST'],
         },
     ],
+
+Another endpoint that's not registered by default is */activate*,
+which works just like its command line counterpart: it takes a model
+version and activates it in the model persister such that the next
+prediction will use the active model.  The handler can be found at
+:func:`palladium.server.activate`.  It requires a request parameter
+called ``model_version``.

palladium/server.py

@@ -12,6 +12,7 @@
 from werkzeug.exceptions import BadRequest
 
 from . import __version__
+from .fit import activate as activate_base
 from .fit import fit as fit_base
 from .interfaces import PredictError
 from .util import args_from_config
@@ -413,6 +414,17 @@ def update_model_cache(model_persister):
         return make_ujson_response({}, status_code=503)
 
 
+@PluggableDecorator('activate_decorators')
+def activate():
+    model_version = int(request.form['model_version'])
+    try:
+        activate_base(model_version=model_version)
+    except LookupError:
+        return make_ujson_response({}, status_code=503)
+    else:
+        return list()
+
+
 def add_url_rule(rule, endpoint=None, view_func=None, app=app, **options):
     if isinstance(view_func, str):
         view_func = resolve_dotted_name(view_func)

palladium/tests/test_server.py

@@ -660,6 +660,45 @@ def test_unavailable(self, update_model_cache, config, jobs, flask_app):
         assert resp.status_code == 503
 
 
+class TestActivateFunctional:
+    @pytest.fixture
+    def activate(self):
+        from palladium.server import activate
+        return activate
+
+    @pytest.fixture
+    def activate_base_mock(self, monkeypatch):
+        func = Mock()
+        monkeypatch.setattr('palladium.server.activate_base', func)
+        return func
+
+    def test_success(self, activate, activate_base_mock, config, flask_app):
+        model_persister = Mock(
+            list_models=lambda: {'be': 'first'},
+            list_properties=lambda: {'be': 'twice'},
+            )
+        config['model_persister'] = model_persister
+        with flask_app.test_request_context(
+            method='POST',
+            data={'model_version': 123},
+        ):
+            resp = activate()
+        assert resp.status_code == 200
+        assert resp.json == {
+            'models': {'be': 'first'},
+            'properties': {'be': 'twice'},
+            }
+
+    def test_lookuperror(self, activate, activate_base_mock, flask_app):
+        activate_base_mock.side_effect = LookupError
+        with flask_app.test_request_context(
+            method='POST',
+            data={'model_version': 123},
+        ):
+            resp = activate()
+        assert resp.status_code == 503
+
+
 def _test_add_url_rule_func():
     return b'A OK'
 

requirements.txt

@@ -3,7 +3,7 @@ certifi==2018.4.16
 chardet==3.0.4
 click==6.7
 docopt==0.6.2
-flask==0.12.2
+flask==1.0.2
 idna==2.6
 itsdangerous==0.24
 Jinja2==2.10