Parameter Server is a shared, multivariable dictionary that is accessible via a network. Nodes use this server to store and retrieve parameters at runtime.
Parameter Server is implemented using XMLRPC and runs inside the ROS master, which means that its API is accessible via normal XMLRPC libraries. XMLRPC is a Remote Procedure Call (RPC) protocol that uses XML to encode its calls and HTTP as a transport mechanism.
Parameter Server uses XMLRPC data types for parameter values, which include
the following:
- 32-bit integers
- Booleans
- Strings
- Doubles
- ISO8601 dates
- Lists
- Base64-encoded binary data
ROS has the rosparam tool to work with Parameter Server. The supported parameters are as follows:
- rosparam list: This lists all the parameters in the server
- rosparam get parameter: This gets the value of a parameter
- rosparam set parameter value: This sets the value of a parameter
- rosparam delete parameter: This deletes a parameter
- rosparam dump file: This saves Parameter Server to a file
- rosparam load file: This loads a file (with parameters) on Parameter Server