Add "inputs" support to pyCA

Adds support for sending configuration to the agent
configuration endpoint in Opencast.
Adds a new config option "inputs". It allows users to specifiy for a
given event which tracks they would like to show up in the final
recording. For example, if the agent is capable of recording both
"presenter/source" and "presentation/source", a user may
select only "presentation/source" as input.

Author: Arnei

etc/pyca.conf

@@ -40,6 +40,13 @@
 # Default: sqlite:///pyca.db
 #database = sqlite:///pyca.db
 
+# Selectable inputs
+# A track will only be ingested if the flavor of the track matches one of the
+# selected inputs.
+# If not specified, all inputs are always selected.
+# Default: inputs = ''
+#inputs = 'presenter/source, presentation/source'
+
 
 [capture]
 
@@ -170,7 +177,7 @@ command          = 'ffmpeg -nostats -re -f lavfi -r 25 -i testsrc -f lavfi -i si
 # org.opencastproject.server.url setting of Opencast.
 # Type: string
 # Default: https://develop.opencast.org
-url              = 'https://develop.opencast.org'
+url              = 'http://localhost:8080'
 
 # Analogue of -k, --insecure option in curl. Allows insercure SSL connections
 # while using HTTPS on the server.

pyca/agentstate.py

@@ -7,7 +7,7 @@
     :license: LGPL – see license.lgpl for more details.
 '''
 
-from pyca.utils import set_service_status, update_agent_state, timestamp
+from pyca.utils import set_service_status, update_agent_state, timestamp, update_agent_config
 from pyca.utils import terminate
 from pyca.config import config
 from pyca.db import Service, ServiceStatus
@@ -34,6 +34,7 @@ def control_loop():
 
         if not terminate():
             update_agent_state()
+            update_agent_config()
 
     logger.info('Shutting down agentstate service')
     set_service_status(Service.AGENTSTATE, ServiceStatus.STOPPED)

pyca/config.py

@@ -20,6 +20,7 @@
 cal_lookahead    = integer(min=0, default=14)
 backup_mode      = boolean(default=false)
 database         = string(default='sqlite:///pyca.db')
+inputs           = force_list(default=list())
 
 [capture]
 directory        = string(default='./recordings')

pyca/ingest.py

@@ -22,6 +22,47 @@
 logger = logging.getLogger(__name__)
 notify = sdnotify.SystemdNotifier()
 
+def inputs_from_event(event):
+    ''' Parse inputs from event attachment
+    '''
+
+    inputs = []
+    for attachment in event.get_data().get('attach'):
+        data = attachment.get('data')
+        if (attachment.get('x-apple-filename') ==
+                'org.opencastproject.capture.agent.properties'):
+            for prop in data.split('\n'):
+                if prop.startswith('capture.device.names'):
+                    param = prop.split('=', 1)
+                    inputs = param[1].split(',')
+                    break
+    return inputs
+
+def is_track_selected(event, flavor):
+    ''' If inputs are configured, check if track was selected
+    '''
+
+    # inputs not configured -> add all
+    inputs_conf = config('agent', 'inputs')
+    if not inputs_conf:
+        logger.info('No inputs in config')
+        return True
+
+    # Get inputs from event attachment
+    inputs_event = inputs_from_event(event)
+
+    # inputs not in attachment -> add all
+    if not inputs_event:
+        logger.info('No inputs in schedule')
+        return True
+
+    # input is selected
+    if flavor in inputs_event:
+        return True
+
+    # input is not selected
+    return False
+
 
 def get_config_params(properties):
     '''Extract the set of configuration parameters from the properties attached
@@ -87,12 +128,15 @@ def ingest(event):
 
     # add track
     for (flavor, track) in event.get_tracks():
-        logger.info('Adding track (%s -> %s)', flavor, track)
-        track = track.encode('ascii', 'ignore')
-        fields = [('mediaPackage', mediapackage), ('flavor', flavor),
-                  ('BODY1', (pycurl.FORM_FILE, track))]
-        mediapackage = http_request(service_url + '/addTrack', fields,
-                                    timeout=0)
+        if is_track_selected(event, flavor):
+            logger.info('Adding track (%s -> %s)', flavor, track)
+            track = track.encode('ascii', 'ignore')
+            fields = [('mediaPackage', mediapackage), ('flavor', flavor),
+                    ('BODY1', (pycurl.FORM_FILE, track))]
+            mediapackage = http_request(service_url + '/addTrack', fields,
+                                        timeout=0)
+        else:
+            logger.info('Not adding track (%s -> %s)', flavor, track)
 
     # ingest
     logger.info('Ingest recording')

pyca/utils.py

@@ -260,6 +260,31 @@ def update_agent_state():
 
     register_ca(status=status)
 
+def update_agent_config():
+    '''Update the current agent configuration in opencast.
+    '''
+
+    if config('agent', 'backup_mode'):
+        return
+    service_endpoint = service('capture.admin')
+    if not service_endpoint:
+        logger.warning('Missing endpoint for updating agent status.')
+        return
+
+    inputs = ",".join(config('agent', 'inputs'))
+    params = [('configuration',
+               '{\'capture.device.names\': \'' + inputs + '\'}'
+             )]
+
+    name = urlquote(config('agent', 'name').encode('utf-8'), safe='')
+    url = f'{service_endpoint[0]}/agents/{name}/configuration'
+    try:
+        response = http_request(url, params).decode('utf-8')
+        if response:
+            logger.info(response)
+    except pycurl.error as e:
+        logger.warning('Could not set configuration of agent %s: %s', name, e)
+
 
 def terminate(shutdown=None):
     '''Mark process as to be terminated.