montydb 0.0.3

A serverless Mongo-like database backed with SQLite.

Monty, Mongo tinified. A literally serverless, Mongo-like database in Python

:construction: Not Ready For Prime Time :construction:

Inspired by TinyDB and the extension TinyMongo.

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MontyDB is:

• A serverless version of MongoDB, against to MongoDB 3.6.4
• Document oriented, of course
• Storage engine pluggable
• Write in pure Python, works on Python 2.7, 3.4, 3.5, 3.6

Install

pip install montydb

Requirements

• pyyaml
• jsonschema
• pymongo (for bson)

Example Code

>>> from montydb import MontyClient
>>> col = MontyClient(":memory:").db.test
>>> col.insert_many([{"stock": "A", "qty": 6}, {"stock": "A", "qty": 2}])

>>> cur = col.find({"stock": "A", "qty": {"$gt": 4}})
>>> next(cur)
{'_id': ObjectId('5ad34e537e8dd45d9c61a456'), 'stock': 'A', 'qty': 6}

Storage Engine Configurations

The configuration process only required on repository creation or modification.

Currently, one repository can only assign one storage engine.

• Memory

Memory storage does not need nor have any configuration, nothing saved to disk.

>>> client = MontyClient(":memory:")

• SQLite

SQLite is the default on-disk storage engine, you can skip the configuration if the default setting is okay.

>>> client = MontyClient("/db/repo")

SQLite default settings, they are infact SQLite pragmas:

connection:
  journal_mode: WAL
write_concern:
  synchronous: 1
  automatic_index: OFF
  busy_timeout: 5000

If you are not happy with the default, use MontyConfigure before get client.

>>> from montydb import MontyClient, MontyConfigure, storage
>>> with MontyConfigure("/db/repo") as cf:  # Auto save config when exit
...     cf.load(storage.SQLiteConfig)       # Load sqlite config
...     cf.config.connection.journal_mode = "DELETE"
...     cf.config.write_concern.busy_timeout = 8000
...
>>> client = MontyClient("/db/repo")  # Running tweaked sqlite storage now

• FlatFile

Not default storage engine, need configuration first before get client.

>>> from montydb import MontyClient, MontyConfigure, storage
>>> with MontyConfigure("/db/repo") as cf:  # Auto save config when exit
...     cf.load(storage.FlatFileConfig)     # Load flatfile config
...
>>> client = MontyClient("/db/repo")  # Running on flatfile storage now

FlatFile default settings:

connection:
  cache_modified: 0  # how many document CRUD cached before flush to disk.

Change storage engine

MontyConfigure will ignore load() if conf.yaml exists, you need to drop() first before changing the storage engine. The documents will remain on disk and conf.yaml will be deleted.

 >>> with MontyConfigure("/db/repo") as cf:
...     cf.drop()
...     cf.load(storage.WhateverConfig)

Reload configuration

MontyClient will reload conf.yaml at the operation right after client.close().

>>> client.close()
>>> col.insert_one({"doc": 1})  # client auto re-open and reload config

After storage engine configuration, you should feel like using MongoDB's Python driver, unless it's not implemented.

Develop Status

See Projects' TODO

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