Expose Scheduler choice in the configuration file

docs/developer/scheduler.rst

 Scheduler classes
 =================
 
-.. autoclass:: zoe_master.scheduler.ZoeScheduler
+.. autoclass:: zoe_master.scheduler.ZoeBaseScheduler
    :members:

zoe_lib/config.py

@@ -86,6 +86,8 @@ def load_configuration(test_conf=None):
 
         argparser.add_argument('--service-log-path', help='Save service logs in this directory, EXPERIMENTAL', default='')
 
+        argparser.add_argument('--scheduler-class', help='Scheduler class to use for scheduling ZApps', default='ZoeSimpleScheduler')
+
         opts = argparser.parse_args()
         if opts.debug:
             argparser.print_values()

zoe_master/entrypoint.py

@@ -20,7 +20,7 @@
 import logging
 
 from zoe_master.master_api import APIManager
-from zoe_master.scheduler import ZoeScheduler
+import zoe_master.scheduler
 from zoe_master.execution_manager import restart_resubmit_scheduler
 from zoe_master.monitor import ZoeMonitor
 from zoe_master.consistency import ZoeSwarmChecker
@@ -56,7 +56,7 @@ def main():
     state = SQLManager(args)
 
     log.info("Initializing scheduler")
-    scheduler = ZoeScheduler()
+    scheduler = getattr(zoe_master.scheduler, config.get_conf().scheduler_class)(state)
 
     monitor = ZoeMonitor(state)
     checker = ZoeSwarmChecker(state)

zoe_master/execution_manager.py

@@ -20,7 +20,7 @@ import logging
 from zoe_lib.sql_manager import Execution, SQLManager
 from zoe_lib import exec_logs
 
-from zoe_master.scheduler import ZoeScheduler
+from zoe_master.scheduler import ZoeBaseScheduler
 
 log = logging.getLogger(__name__)
 
@@ -32,18 +32,18 @@ def _digest_application_description(state: SQLManager, execution: Execution):
             state.service_new(execution.id, name, service_descr['name'], service_descr)
 
 
-def execution_submit(state: SQLManager, scheduler: ZoeScheduler, execution: Execution):
+def execution_submit(state: SQLManager, scheduler: ZoeBaseScheduler, execution: Execution):
     """Submit a new execution to the scheduler."""
     _digest_application_description(state, execution)
     scheduler.incoming(execution)
 
 
-def execution_terminate(scheduler: ZoeScheduler, execution: Execution):
+def execution_terminate(scheduler: ZoeBaseScheduler, execution: Execution):
     """Remove an execution form the scheduler."""
     scheduler.terminate(execution)
 
 
-def restart_resubmit_scheduler(state: SQLManager, scheduler: ZoeScheduler):
+def restart_resubmit_scheduler(state: SQLManager, scheduler: ZoeBaseScheduler):
     """Restart work after a restart of the process."""
     sched_execs = state.execution_list(status=Execution.SCHEDULED_STATUS)
     for e in sched_execs:

zoe_master/master_api.py

@@ -26,14 +26,14 @@ from zoe_lib.sql_manager import SQLManager
 
 import zoe_master.execution_manager
 from zoe_master.exceptions import ZoeException
-from zoe_master.scheduler import ZoeScheduler
+from zoe_master.scheduler import ZoeBaseScheduler
 
 log = logging.getLogger(__name__)
 
 
 class APIManager:
     """The API Manager."""
-    def __init__(self, metrics: BaseMetricSender, scheduler: ZoeScheduler, state: SQLManager) -> None:
+    def __init__(self, metrics: BaseMetricSender, scheduler: ZoeBaseScheduler, state: SQLManager) -> None:
         self.context = zmq.Context()
         self.zmq_s = self.context.socket(zmq.REP)
         self.listen_uri = config.get_conf().api_listen_uri
@@ -84,7 +84,7 @@ class APIManager:
                 exec_id = message['exec_id']
                 execution = self.state.execution_list(id=exec_id, only_one=True)
                 if execution is not None:
-                    zoe_master.execution_manager.execution_delete(self.scheduler, execution)
+                    zoe_master.execution_manager.execution_delete(execution)
                 self._reply_ok()
             elif message['command'] == 'scheduler_stats':
                 data = self.scheduler.stats()

zoe_master/scheduler/__init__.py

+# Copyright (c) 2017, Daniele Venzano
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""The Zoe schedulers"""
+
+from .base_scheduler import ZoeBaseScheduler
+from .scheduler import ZoeSimpleScheduler