Adds handshaking

tagserver.py

@@ -17,6 +17,8 @@ import json
 web_address = "http://localhost:3000"
 scan_rate = 30  # seconds
 save_all = "test"  # use True, False, or any string
+plc_handshake_tag = None
+last_handshake_time = 0
 
 tag_store = {}
 device_types = {}
@@ -69,6 +71,17 @@ def main():
         print("Error getting save-all: {}".format(e))
         print("I'll just use {}  as the save-all parameter...".format(save_all))
 
+    try:
+        handshake_req_data = {"where": {"parameter": "plc_handshake_tag"}}
+        handshake_req = requests.get('{}/config'.format(web_address), params=handshake_req_data)
+        handshake_try = json.loads(handshake_req.text)
+        if len(handshake_req_try) > 0:
+            plc_handshake_tag = handshake_try[0]['val']
+            plc_handshake_tag = Tag("PLC Handshake", plc_handshake_tag, 0, "BOOL", 0, 0)
+    except Exception, e:
+        print("Error getting PLC Handshake Tag: {}".format(e))
+        print("I'll just use {}  as the PLC Handshake Tag parameter...".format(plc_handshake_tag))
+
     for t in tags:
         # name, tag, db_id, data_type, change_threshold, guarantee_sec, mapFn=None, device_type='CLX', ip_address='192.168.1.10'):
         tag_store[t['name']] = Tag(t['name'], t['tag'], t['id'], t['data_type'], t['change_threshold'], t['guarantee_sec'], mapFn=t['map_function'], ip_address=t['deviceID']['address'], device_type=device_types[t['deviceID']['device_type']])
@@ -80,6 +93,11 @@ def main():
             except:
                 print("ERROR EVALUATING {}".format(tag))
                 traceback.print_exc()
+
+        if plc_handshake_tag:
+            if time.time() - last_handshake_time > 30.0:
+                plc_handshake_tag.write(1)
+                last_handshake_time = time.time()
         time.sleep(scan_rate)
 
 if __name__ == '__main__':