Skip to main content

Simple File-based KV-Store

Project description

# kvfile

[![Travis](https://img.shields.io/travis/akariv/kvfile/master.svg)](https://travis-ci.org/akariv/kvfile)
[![Coveralls](http://img.shields.io/coveralls/akariv/kvfile.svg?branch=master)](https://coveralls.io/r/akariv/kvfile?branch=master)

A simple Key-Value store that's file based - so can accommodate large data sets with a small memory footprint.

Internally will use the faster `leveldb` as a storage backend or `sqlite3` as fallback if `leveldb` is not available.

## The Basics

The API should feel familiar to anyone working with Python.
It exposes `get`, `keys` and `items` for reading from the DB, and `set` for setting a value in the DB.

### Initializing

```python
import datetime
import decimal

from kvfile import KVFile

kv = KVFile()
```

### Setting values

```python
kv.set('s', 'value')
kv.set('i', 123)
kv.set('d', datetime.datetime.fromtimestamp(12325))
kv.set('n', decimal.Decimal('1234.56'))
kv.set('ss', set(range(10)))
kv.set('o', dict(d=decimal.Decimal('1234.58'),
n=datetime.datetime.fromtimestamp(12325)))
```

### Getting values

```python
assert kv.get('s') == 'value'
assert kv.get('i') == 123
assert kv.get('d') == datetime.datetime.fromtimestamp(12325)
assert kv.get('n') == decimal.Decimal('1234.56')
assert kv.get('ss') == set(range(10))
assert kv.get('o') == dict(d=decimal.Decimal('1234.58'),
n=datetime.datetime.fromtimestamp(12325))
```

### Listing values

`keys()` and `items()` methods return a generator yielding the values for efficient stream processing.

The returned data is sorted ascending (by default) based on the keys

```python
assert list(kv.keys()) == ['d', 'i', 'n', 'o', 's', 'ss']
assert list(kv.items()) == [
('d', datetime.datetime.fromtimestamp(12325)),
('i', 123),
('n', decimal.Decimal('1234.56')),
('o', {'d': decimal.Decimal('1234.58'),
'n': datetime.datetime.fromtimestamp(12325)}),
('s', 'value'),
('ss', {0, 1, 2, 3, 4, 5, 6, 7, 8, 9})
]
```

Set the `reverse` argument to True for the `keys()` and `items()` methods to sort in descending order.

### Bulk inserting data

The SQLite DB backend can be very slow when bulk inserting data. You can use the insert method to insert efficiently in bulk.

```python
kv.insert(((str(i), ':{}'.format(i)) for i in range(50000)))
```

The batch size is 1000 by default, you should modify it depending on the size of your data and available memory.

```python
kv.insert(((str(i), ':{}'.format(i)) for i in range(50000)), batch_size=40000)
```

If you are inserting data from a generator and need to use the inserted data, use `insert_generator` method:

```python
for key, value in kv.insert_generator(((str(i), ':{}'.format(i)) for i in range(50)), batch_size=10):
print(key, value)
```

## Installing leveldb

On Debian based Linux:
```bash
$ apt-get install libleveldb-dev libleveldb1
```

On Alpine based Linux:
```bash
$ apk --repository http://dl-3.alpinelinux.org/alpine/edge/testing/ --update add leveldb leveldb-dev
```

On OS X:
```bash
$ brew install leveldb
```

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

kvfile-0.0.4.tar.gz (7.0 kB view details)

Uploaded Source

Built Distribution

kvfile-0.0.4-py2.py3-none-any.whl (5.7 kB view details)

Uploaded Python 2 Python 3

File details

Details for the file kvfile-0.0.4.tar.gz.

File metadata

  • Download URL: kvfile-0.0.4.tar.gz
  • Upload date:
  • Size: 7.0 kB
  • Tags: Source
  • Uploaded using Trusted Publishing? No
  • Uploaded via: twine/1.12.1 pkginfo/1.4.2 requests/2.19.1 setuptools/40.4.3 requests-toolbelt/0.8.0 tqdm/4.26.0 CPython/3.6.3

File hashes

Hashes for kvfile-0.0.4.tar.gz
Algorithm Hash digest
SHA256 2bee02a9ccd087e3743baf63a63a88ee87101f8d65797844e4d6986dea8034c6
MD5 da9b91634770987f9ab6ca35c159587a
BLAKE2b-256 bd50a8b063d493dcbdbdbcc451ac57b226a80b449adc847b60eec48620937dec

See more details on using hashes here.

Provenance

File details

Details for the file kvfile-0.0.4-py2.py3-none-any.whl.

File metadata

  • Download URL: kvfile-0.0.4-py2.py3-none-any.whl
  • Upload date:
  • Size: 5.7 kB
  • Tags: Python 2, Python 3
  • Uploaded using Trusted Publishing? No
  • Uploaded via: twine/1.12.1 pkginfo/1.4.2 requests/2.19.1 setuptools/40.4.3 requests-toolbelt/0.8.0 tqdm/4.26.0 CPython/3.6.3

File hashes

Hashes for kvfile-0.0.4-py2.py3-none-any.whl
Algorithm Hash digest
SHA256 fb9131e0c82d22cb0ac988b75a1870492ad708089d965cadae5a98c1f786ec14
MD5 80a07e7aa7ae4c8032582c69178a1c1e
BLAKE2b-256 d0178b995a4e4cdf1f68ca8e1f020f85e8cd5b4db303b3f1b2883d7cdb22c7d9

See more details on using hashes here.

Provenance

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page