Monitor Spec

specs/monitor.rst

@@ -0,0 +1,82 @@
+=====================
+Monitor Specification
+=====================
+
+Introduction
+============
+
+A simple passive monitor (like the name implies) that runs in the background and streams to the outside world
+the "value" of a (set) of parameters.
+
+
+The GUI for the monitor is not part of qcodes.
+
+Monitoring is implemented by reading the last know value of that parameter.
+
+Requirements
+============
+
+The Monitor class should meet the following requirements:
+
+Basics
+---------
+
+#. Monitor any type and number of parameters
+#. Groups by instrument or lack thereof
+#. Cheap messaging
+#. Non blocking
+#. Thread safe
+
+Creation
+------------
+
+#. A monitor can be created at any point
+#. There can be only one monitor running
+#. The websocket address:port can be specified in the config as :
+
+   :: 
+
+     monitor_addres="address:port"
+
+
+API
+---
+
+#. Monitor(*parameters)
+   Creates and starts a thread that streams json over a websocket.
+   If a monitor is already running, it will be stopped.
+
+#. Monitor.show()
+   Raises the window / shows the window.
+   This must be implemented by the users.
+
+
+#. JSON endpoint
+   The websocket streams the following data structure:
+
+   ::
+
+    Message =
+    {
+        ts: Float  # when did the monitor last stent data
+        parameters: List Parameters
+    }
+
+    Parameters =
+        { instrument : Maybe String
+        , parameters : List Parameter
+        }
+
+
+    Parameter =
+        { name : String
+        , unit : Maybe String
+        , value : Maybe String
+        , ts : Maybe Float # when was the parameter value last updated
+        }
+
+
+Open Issues
+===========
+
+# Integration with the station