Improved snapshot interface with saving snapshot files in the OP configuration. Added app support for stabilizing XTCAV. Added a BSacquisition based on BSCache

ext/bscacquisition.py

@@ -0,0 +1,42 @@
+import zmq
+import h5py
+
+
+from bstrd import BSCache
+from slic.core.acquisition.acquisition import Acquisition
+from slic.core.acquisition import BSAcquisition, PVAcquisition
+
+# class using the BSQueue to avoid to reestablish a stream for each step.
+
+class BSCAcquisition(Acquisition):
+            
+    def release(self):
+        if not self.queue == None:
+            del self.queue
+            self.queue = None
+
+    def _acquire(self, filename, channels=None, data_base_dir=None, scan_info=None, n_pulses=100, **kwargs):
+        if not hasattr(self,'queue'):
+            self.queue = getStream(channels)
+        elif not self.queue:
+            self.queue = getStream(channels)
+            
+        self.queue.flush()
+        print('Acquiring',n_pulses,'samples')
+        data = []
+        for i in range(n_pulses):
+            data.append(self.queue.__next__())
+        hid = h5py.File(filename,'w')
+        gid = hid.create_group(channels[0])
+        for key in data[0].keys():
+            gid.create_dataset(key, data = [rec[key].value for rec in data])
+        hid.close()        
+        
+
+def getStream(channels):
+    print('Generating stream with channels:',channels)
+    bs = BSCache(100000,10000)   # 1 second time out, capazity for 100 second.
+    bs.get_vars(channels)
+    return bs
+    
+