Features

• makes sure multiple processes are able to create unique ids

• optimized by requesting multiple ids with a single Elasticsearch request

Elasticsearch Setup

The sequences must be assigned to an elasticsearch client instance:

>>> from elasticsearch import Elasticsearch
>>> es_client = Elasticsearch(['localhost:%s' % crate_port])

To globally assign the client to all sequences in the application the client can be assigned to the class property ES:

>>> from lovely.essequence import Sequence
>>> Sequence.ES = es_client

Usage

There is a Sequence class:

>>> from lovely.essequence import Sequence

It must be instantiated with the name of a sequence:

>>> s1 = Sequence('s1')

Now the iids can be requested:

>>> s1.next()
1
>>> s1.next()
2

Multiple sequence instances for the same sequence name use the same bulk:

>>> s2 = Sequence('s1', bulk_size=100)
>>> s2.next()
3

After the bulk size has been consumed the request of the next bulk is transparently handled inside the next method:: Consume all the cached ids from s1:

>>> for i in range(10): s1.next()
4
5
6
7
8
9
10
11
12
13

Multiple independed sequences can be used:

>>> other = Sequence('other')
>>> other.next()
1

Transforming the provided iid

A transformation function can be provided to transform the provided integer value into something else when calling next:

>>> asstring = Sequence('other', transform=str)
>>> isinstance(asstring.next(), str)
True

>>> def transformer(iid):
...     return {'iid': iid}
>>> Sequence('other', transform=transformer).next()
{'iid': 3}

Resetting a Sequence

For testing purposes it is possible to reset a sequence.