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[aguschin]

Closes #8

[aguschin]

This PR makes dumping registry state possible. E.g. if you run

bash showcase.sh
ipython -c "from gitops import init_registry; reg = init_registry(); import json; reg.state.dict()"

You'll get something like

{'objects': [{'category': 'model',
   'name': 'models/random-forest.pkl',
   'versions': [{'category': 'model',
     'object': 'models/random-forest.pkl',
     'name': 'v1',
     'creation_date': datetime.datetime(2022, 1, 24, 14, 53, 46),
     'author': 'Alexander Guschin',
     'commit_hexsha': '77c2f7ede42c0c71d2d2de55a1f864ab33d8d161',
     'unregistered_date': None},
    {'category': 'model',
     'object': 'models/random-forest.pkl',
     'name': 'v2',
     'creation_date': datetime.datetime(2022, 1, 24, 14, 53, 49),
     'author': 'Alexander Guschin',
     'commit_hexsha': '80c29c5b63133703c1c76ec3062a718637a0b58e',
     'unregistered_date': None}],
   'labels': [{'category': 'model',
     'object': 'models/random-forest.pkl',
     'version': 'v1',
     'name': 'production',
     'creation_date': datetime.datetime(2022, 1, 24, 14, 53, 52),
     'author': 'Alexander Guschin',
     'commit_hexsha': '77c2f7ede42c0c71d2d2de55a1f864ab33d8d161',
     'unregistered_date': None},
    {'category': 'model',
     'object': 'models/random-forest.pkl',
     'version': 'v2',
     'name': 'staging',
     'creation_date': datetime.datetime(2022, 1, 24, 14, 53, 54),
     'author': 'Alexander Guschin',
     'commit_hexsha': '80c29c5b63133703c1c76ec3062a718637a0b58e',
     'unregistered_date': None},
    {'category': 'model',
     'object': 'models/random-forest.pkl',
     'version': 'v2',
     'name': 'production',
     'creation_date': datetime.datetime(2022, 1, 24, 14, 53, 55),
     'author': 'Alexander Guschin',
     'commit_hexsha': '80c29c5b63133703c1c76ec3062a718637a0b58e',
     'unregistered_date': None},
    {'category': 'model',
     'object': 'models/random-forest.pkl',
     'version': 'v1',
     'name': 'production',
     'creation_date': datetime.datetime(2022, 1, 24, 14, 53, 57),
     'author': 'Alexander Guschin',
     'commit_hexsha': '77c2f7ede42c0c71d2d2de55a1f864ab33d8d161',
     'unregistered_date': None}]},
  {'category': 'model',
   'name': 'models/neural-network.pkl',
   'versions': [{'category': 'model',
     'object': 'models/neural-network.pkl',
     'name': 'v1',
     'creation_date': datetime.datetime(2022, 1, 24, 14, 53, 47),
     'author': 'Alexander Guschin',
     'commit_hexsha': '77c2f7ede42c0c71d2d2de55a1f864ab33d8d161',
     'unregistered_date': None}],
   'labels': [{'category': 'model',
     'object': 'models/neural-network.pkl',
     'version': 'v1',
     'name': 'staging',
     'creation_date': datetime.datetime(2022, 1, 24, 14, 53, 50),
     'author': 'Alexander Guschin',
     'commit_hexsha': '77c2f7ede42c0c71d2d2de55a1f864ab33d8d161',
     'unregistered_date': None}]}]}

Some information is missing (e.g. user email, or tagging message), but can be added.

Also, as the next step, we should try to match this with branch-based and file-based approaches to see how it works out.