RasdaPy_Cannot release connection to server by database.close()

[Bang Pham Huu]

Normally rasdaman has 9 rasservers to serve queries from client. RasdaPy (​https://pypi.python.org/pypi/rasdapy) is one of client as same as Rasql.

In the API, it has a feature to close the connection to rasserver (database.close()). However, it doesn't work as the python script cannot close the connection (the script hangs at closing connection).

Hence, run this test script (​https://pastebin.com/g5j2uKFN) 10 times will cause error about no available servers and other client like rasql will have same error.

  File "test.py", line 147, in <module>
    setUp()
  File "test.py", line 18, in setUp
    db = con.database("RASBASE")
  File "/home/rasdaman/.local/lib/python2.7/site-packages/rasdapy/core.py", line 148, in database
    database = Database(self, name)
  File "/home/rasdaman/.local/lib/python2.7/site-packages/rasdapy/core.py", line 172, in __init__
    self.open()
  File "/home/rasdaman/.local/lib/python2.7/site-packages/rasdapy/core.py", line 184, in open
    self.name)
  File "/home/rasdaman/.local/lib/python2.7/site-packages/rasdapy/remote_procedures.py", line 73, in rasmgr_open_db
    _TIMEOUT_SECONDS)
  File "/home/rasdaman/.local/lib/python2.7/site-packages/grpc/beta/_client_adaptations.py", line 310, in __call__
    self._request_serializer, self._response_deserializer)
  File "/home/rasdaman/.local/lib/python2.7/site-packages/grpc/beta/_client_adaptations.py", line 196, in _blocking_unary_unary
    raise _abortion_error(rpc_error_call)
grpc.framework.interfaces.face.face.RemoteError: RemoteError(code=StatusCode.UNKNOWN, details=",
There is no available server for the client.")