litecounter

Very simple counter implemented on top of SQLite

Why?

You can use this to implement a persistent counter. It also uses some SQLite syntax to initialize keys to 0 when the counter starts on them, just as if you had a collections.defaultdict where the default is 0.

Installation

pip install litecounter

IMPORTANT: This package uses SQLite's UPSERT statment so it needs to run at least with SQLite version 3.24.0 (released 2018-06-04).

If you need to run the latest version, you can use pysqlite3.

All the litements libraries (including this one) accept either a filename or an already created sqlite connection. Apart from that, if you have pysqlite3 installed it will use that instead of the sqlite3 module from the standard library.

Examples

The examples are taken from the tests in tests.ipynb

TEST_1 = "key_test_1"
TEST_2 = "key_test_2"

from litecounter import SQLCounter

counter = SQLCounter(":memory:")

# Increment from 0 to 20

for _ in range(20):
    counter.incr(TEST_1)

assert counter.count(TEST_1) == 20

# Decrement 10 (from 20 to 10)

for _ in range(10):
    counter.decr(TEST_1)

assert counter.count(TEST_1) == 10

# From 0 to -10, then -20.

for _ in range(10):
    counter.decr(TEST_2)

assert counter.count(TEST_2) == -10

for _ in range(10):
    counter.decr(TEST_2)

assert counter.count(TEST_2) == -20

# Set fist key to 0.

counter.zero(TEST_1)

assert counter.count(TEST_1) == 0

# Increment the second test key by 100, from -20 to 80.

for _ in range(100):
    counter.incr(TEST_2)

assert counter.count(TEST_2) == 80

# Delete key works

assert counter.count(TEST_1) == 0

counter.delete(TEST_1)

assert counter.count(TEST_1) is None

# When the key does not exist, delete just ignores it

counter.delete("foobar")

# Check `__repr__`

import random

for key in ["foo", "bar", "baz", "foobar", "asd", TEST_1]:
    for _ in range(random.randint(0,10)):
        counter.incr(key)

print(counter)

# SQLCounter(dbname=':memory:', items=[('key_test_2', 80), ('foo', 8), ('baz', 5), ('foobar', 6), ('key_test_1', 10)])

Meta

Ricardo Ander-Egg Aguilar – @ricardoanderegg –

• ricardoanderegg.com
• github.com/polyrand
• linkedin.com/in/ricardoanderegg

Distributed under the MIT license. See LICENSE for more information.

Contributing

The only hard rules for the project are:

• No extra dependencies allowed
• No extra files, everything must be inside the main module's .py file.
• Tests must be inside the tests.ipynb notebook.