Run a device server with the File Database#
For device servers not able to access the Tango Database (most of the time due to network route or security reasons) or just because it is more convenient for testing, it is possible to start device servers using a file instead of a real Tango database.
The File Database has the following limitations:
There’s no check that the same device server is running twice
There’s no device or attribute alias name support
If several device servers are running on the same host, the user must manually manage a list of network ports already in use
To use the File Database, pass the following command line option to the device server:
-file=<file name>
In this case the getting, setting and deletion of all properties are handled using the specified file instead of the Tango database. The file is a plaintext file and follows a well-defined syntax with predefined keywords and is called a property file. The simplest way to generate the file for a specific device server is to use Jive.
The Tango database is not only used to store device configuration parameters, it is also used to store device network access parameters, for example the Interoperable Tango Reference. Therefore to allow an application to connect to a device hosted by a device server using a file instead of the standard database, you need to start it on a pre-defined port using one of the underlying ORB options called endPoint. For example, to start your device server:
myserver myinstance_name -file=path/serverFile -ORBendPoint giop:tcp::<port>
Assuming the device id12/rb/1 runs on host fish with port 1234, clients can then connect to it via the Tango Resource Locator (TRL):
tango://fish:1234/id12/rb/1#dbase=no