Issues getting this tool to run

[cb109]

• Django Migration Snapshots version: 0.5.1
• Django version: 3.2
• Python version: 3.7.9
• Operating System: Ubuntu 20.04

Description

I ran into some issues trying to use your tool as documented:

• The documentation is missing the fact that we need to enable the mechanism first via MIGRATION_SNAPSHOT_MODEL = True
• MIGRATION_SNAPSHOT_DIR has no effect until we run makemigrations, as you are directly using the value in a FileField upload_to option. Changing the value would require another migration afterwards. I think you can define your FileField upload_to as a module-level function instead that reads from current settings, then no migrations are needed at all, which would be a more intuitive API.
• Your date commandline argument defaults to the empty string, but will still be passed as date_end to dateutil.parser.parse(), failing with dateutil.parser._parser.ParserError: String does not contain a date:. You should make this optional, handling the empty/None default.
• If record_snapshot() fails (like with the problem above), you will still try and remove the files that have not been created in the finally: block, which raises a different exception (os.remove(graph_name) FileNotFoundError: [Errno 2] No such file or directory: 'migration_snapshot') and somewhat overshadows any actual underlying issue. Maybe there's a better way to handle this, at least using a more explicit error like failed to create graph file, reason:.
• Changing DEFAULT_SNAPSHOT_FORMAT had no effect for me, would always try to create a .pdf output file