The GREN Map DB node uses Django Q for two purposes: to schedule polling events, and to execute long-running tasks asynchronously.
We can import a topology file into the server in two ways: using the admin page and using the /grenml_import/upload API endpoint.
The endpoint accepts GRENML files. The GRENMap server verifies an uploaded file conforms to the GRENML schema, which is part of the GRENML library source code.
In addition to GRENML files, the upload function in the admin page also accepts Excel spreadsheets.
Both code paths rely on a Django signal triggered by saving the ImportFile model for an uploaded file. The signal handler posts a new task to the queue. The task contains references to the ImportFile model just created and to a function that parses the file and inserts records for network elements in the database.