Mongomancy

Description

Project contains abstraction of pymongo driver for automatic reconnect on master switch in remote MongoDB cluster. It also provides data definition layer.

Core of mongo_driver is the Engine class, handling queries reconnection with notification to registered reconnect hooks. Database creates Collections by their definitions. Database hooks itself to engine reconnect event, so it can switch internal state of database's collections instances.

    classDiagram
        Executor <|-- Engine : implements
        Database o-- Executor
        Database *-- Collection
        Database o-- CollectionDefinition
        Collection o-- Executor
        CollectionDefinition *-- Index
        CollectionDefinition *-- Document
        
        class Executor{
            <<abstract>>
            reconnect()
            register_hook(reconnect_hook_func)
            find_one(collection: pymongo.collection.Collection, ...)
            other_collection_methods(collection: pymongo.collection.Collection, ...)
        }
        
        class Engine{
            +client: MongoClient
            -_retry_command(collection, command, ...)
            dispose()
            reconnect()
            register_hook(reconnect_hook_func)
            find_one(collection: pymongo.collection.Collection, ...)
            other_collection_methods(collection: pymongo.collection.Collection, ...)
        }
    
        class Collection{
            +dialect_entity: pymongo.collection.Collection
            +engine: Executor
            +find_one(...)
            other_collection_methods()
        }
        
        class Document{
            +unique_key: Optional[BsonDict]
            +data: BsonDict
        }
    
        class CollectionDefinition{
            +name: str
            +indices: Sequence[Index]
            +default_docs: Sequence[Document]
        }
    
        class Index{
            +fields: OrderedDictType[str, Union[str, int]]
            +name: Optional[str]
            +unique: Optional[bool]
            field_for_mongo() -> List[Tuple[str, Union[str, int]]]
        }
    
        class Database{
            +engine: Executor
            +topology: List[types.CollectionDefinition]
            -_database: pymongo.database.Database
            -_collections: Dict[str, Collection]
            invalidate_cache_hook(source: Engine) 
            get_collection(name: str) -> Collection
            extend(*new_definitions: types.CollectionDefinition)
            create_all(skip_existing: bool)
            ping() -> bool
        }

Installation

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Usage

import logging
from mongomancy import Engine, Database, CollectionDefinition, Index

engine = Engine("localhost", 27017)
logger = logging.getLogger(__name__)
db = Database(engine=engine, logger=logger)
game = CollectionDefinition(name="game", indices=[Index(fields={"genre": 1})])
player = CollectionDefinition(name="player", indices=[Index(fields={"player_id": 1}, unique=True)])
db.add_collection(game)
db.add_collection(player)
db.create_all()
db["game"].find({"genre": "adventure"})

Tests

You can run tests with coverage tracing:

python -m coverage run -m unittest tests/test_* -v 

To generate coverage report:

python -m coverage html   

Build

Clone repo and set up your pypi repo account credentials on build for build environment.

• Move to package repo:

  cd ~/git/mongomancy

• Install requirements:

  python -m pip install -Ur requirements.txt

• Clean old build fragments:

  rm -rf ./dist ./build ./mongomancy/mongomancy.egg-info

• Build new package:

  python -m build

• Upload new package:

  python -m twine upload dist/*