Autotest Web Frontend Implementation details

Here we outline the building blocks and implementation details of the autotest web interface.


Here’s a broad overview of how the system fits together:


  • The Django RPC server is an RPC server, written using the Django framework. It functions as a web server, accepting RPCs as HTTP POST requests, querying the MySQL database as necessary, and returning results. In a production environment, it runs within Apache using mod_python
    • The AFE server code lives under frontend/afe and uses the autotest_web database.
    • The TKO server code lives under new_tko/tko and uses the tko database.
    • In both servers, the RPC entry points are defined in
    • All RPC POST requests go to a single URL, (afe|new_tko)/server/rpc/. They get dispatched to RPC methods by the code in See Django documentation for an explanation of how HTTP requests get mapped to Python code using URLconfs.
    • Database models live in See Django documentation for an explanation of models.
  • RPC calls and responses are encoded according to the JSON-RPC protocol.
    • JSON is a simple data representation format based on Javascript. See
    • JSON-RPC is a very simple standard for representing RPC calls and responses in JSON. See
    • RPCs are made by sending a POST request to the server with the POST data containing the JSON-encoded request. The response text is a JSON-encoded response.
      • On the server, the code for serializing JSON lives at frontend/afe/simplejson. The code for forming and dispatching JSON-RPC requests lives at frontend/afe/json_rpc.
      • The CLI uses the same code for serializing JSON-RPC.
      • The GWT client uses GWT’s builtin JSON library for serializing JSON. The code for handling JSON-RPC requests is in autotest.common.JsonRpcProxy and friends.
  • The GWT client is a browser-based client for AFE and TKO (technically, there are two separate clients). It’s written using Google Web Toolkit (GWT), a framework for writing browser apps in Java and having them compiled to Javascript. See
    • More details…
  • The CLI is a command-line Python application that makes calls to the RPC server. It lives under the cli directory. cli/autotest-rpc-client is the main entry point.