mlzboy/sqlite3worker

A threadsafe sqlite worker for Python

Sqlite3Worker

A threadsafe sqlite worker.

This library implements a thread pool pattern with sqlite3 being the desired output.

sqllite3 implementation lacks the ability to safely modify the sqlite3 database with multiple threads outside of the compile time options. This library was created to address this by bringing the responsibility of managing the threads to the python layer and is agnostic to the server setup of sqlite3.

Install

Installation is via the usual setup.py method:

sudo python setup.py install

Alternatively one can use pip to install directly from the git repository without having to clone first:

sudo pip install git+https://github.com/palantir/sqlite3worker#egg=sqlite3worker

One may also use pip to install on a per-user basis without requiring super-user permissions:

pip install --user git+https://github.com/palantir/sqlite3worker#egg=sqlite3worker

Example

from sqlite3worker import Sqlite3Worker

sql_worker = Sqlite3Worker("/tmp/test.sqlite")
sql_worker.execute("CREATE TABLE tester (timestamp DATETIME, uuid TEXT)")
sql_worker.execute("INSERT into tester values (?, ?)", ("2010-01-01 13:00:00", "bow"))
sql_worker.execute("INSERT into tester values (?, ?)", ("2011-02-02 14:14:14", "dog"))

results = sql_worker.execute("SELECT * from tester")
for timestamp, uuid in results:
    print(timestamp, uuid)

sql_worker.close()

When to use sqlite3worker

If you have multiple threads all needing to write to a sqlite3 database this library will serialize the sqlite3 write requests.

When NOT to use sqlite3worker

If your code DOES NOT use multiple threads then you don't need to use a thread safe sqlite3 implementation.

If you need multiple applications to write to a sqlite3 db then sqlite3worker will not protect you from corrupting the data.

Internals

The library creates a queue to manage multiple queries sent to the database. Instead of directly calling the sqlite3 interface, you will call the Sqlite3Worker which inserts your query into a Queue.Queue() object. The queries are processed in the order that they are inserted into the queue (first in, first out). In order to ensure that the multiple threads are managed in the same queue, you will need to pass the same Sqlite3Worker object to each thread.

Python docs for sqlite3

https://docs.python.org/2/library/sqlite3.html