web: Migrate web runner to REST API

This pull request updates the web runner to remove its hard dependency on a 
direct database connection. Instead, it now communicates via the REST API.

* Add endpoint for scheduling simulation jobs
* Create simple API client for web runner
* Remove direct database connection from web runner
* Improve validation of API input/output data

Implements #144 

1 files changed, 105 insertions, 0 deletions

diff --git a/opendc-web/opendc-web-api/opendc/api/jobs.py b/opendc-web/opendc-web-api/opendc/api/jobs.py
new file mode 100644
index 00000000..6fb0522b
--- /dev/null
+++ b/opendc-web/opendc-web-api/opendc/api/jobs.py
@@ -0,0 +1,105 @@
+#  Copyright (c) 2021 AtLarge Research
+#
+#  Permission is hereby granted, free of charge, to any person obtaining a copy
+#  of this software and associated documentation files (the "Software"), to deal
+#  in the Software without restriction, including without limitation the rights
+#  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+#  copies of the Software, and to permit persons to whom the Software is
+#  furnished to do so, subject to the following conditions:
+#
+#  The above copyright notice and this permission notice shall be included in all
+#  copies or substantial portions of the Software.
+#
+#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+#  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+#  SOFTWARE.
+from flask import request
+from flask_restful import Resource
+from marshmallow import fields, Schema, validate
+from werkzeug.exceptions import BadRequest, Conflict
+
+from opendc.exts import requires_auth, requires_scope
+from opendc.models.scenario import Scenario
+
+
+def convert_to_job(scenario):
+    """Convert a scenario to a job.
+    """
+    return JobSchema().dump({
+        '_id': scenario['_id'],
+        'scenarioId': scenario['_id'],
+        'state': scenario['simulation']['state'],
+        'heartbeat': scenario['simulation'].get('heartbeat', None),
+        'results': scenario.get('results', {})
+    })
+
+
+class JobSchema(Schema):
+    """
+    Schema representing a simulation job.
+    """
+    _id = fields.String(dump_only=True)
+    scenarioId = fields.String(dump_only=True)
+    state = fields.String(required=True,
+                          validate=validate.OneOf(["QUEUED", "CLAIMED", "RUNNING", "FINISHED", "FAILED"]))
+    heartbeat = fields.DateTime()
+    results = fields.Dict()
+
+
+class JobList(Resource):
+    """
+    Resource representing the list of available jobs.
+    """
+    method_decorators = [requires_auth, requires_scope('runner')]
+
+    def get(self):
+        """Get all available jobs."""
+        jobs = Scenario.get_jobs()
+        data = list(map(convert_to_job, jobs.obj))
+        return {'data': data}
+
+
+class Job(Resource):
+    """
+    Resource representing a single job.
+    """
+    method_decorators = [requires_auth, requires_scope('runner')]
+
+    def get(self, job_id):
+        """Get the details of a single job."""
+        job = Scenario.from_id(job_id)
+        job.check_exists()
+        data = convert_to_job(job.obj)
+        return {'data': data}
+
+    def post(self, job_id):
+        """Update the details of a single job."""
+        action = JobSchema(only=('state', 'results')).load(request.json)
+
+        job = Scenario.from_id(job_id)
+        job.check_exists()
+
+        old_state = job.obj['simulation']['state']
+        new_state = action['state']
+
+        if old_state == new_state:
+            data = job.update_state(new_state)
+        elif (old_state, new_state) == ('QUEUED', 'CLAIMED'):
+            data = job.update_state('CLAIMED')
+        elif (old_state, new_state) == ('CLAIMED', 'RUNNING'):
+            data = job.update_state('RUNNING')
+        elif (old_state, new_state) == ('RUNNING', 'FINISHED'):
+            data = job.update_state('FINISHED', results=action.get('results', None))
+        elif old_state in ('CLAIMED', 'RUNNING') and new_state == 'FAILED':
+            data = job.update_state('FAILED')
+        else:
+            raise BadRequest('Invalid state transition')
+
+        if not data:
+            raise Conflict('State conflict')
+
+        return {'data': convert_to_job(data)}