======== proxenos

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A Python toolkit for Rendezvous/Highest Random Weight (HRW) hash based routing.

.. code-block:: pycon

import proxenos.mappers.consul import proxenos.rendezvous mapper = proxenos.mappers.consul.ConsulClusterMapper( ... host='localhost', port=8500) mapper.update() mapper.cluster {SocketAddress(host=IPAddress('::'), port=8000), SocketAddress(host=IPAddress('::'), port=8001), SocketAddress(host=IPAddress('::'), port=8300), SocketAddress(host=IPAddress('::'), port=8500)} mapper.select('github.com', proxenos.rendezvous.HashMethod.SIPHASH) SocketAddress(host=IPAddress('::'), port=8001)

.. code-block:: shell

$ proxenos select -b consul -h localhost -p 8500 github.com 0.0.0.0:8300

Features

• Support for multiple service discovery backends possible. Currently only support for Consul is implemented, but other backends coming eventually.
• Supports many different hash functions and PRFs. The default hashing method is the SipHash <https://131002.net/siphash/>_ PRF.
• Provides a command-line interface for quickly testing/debugging node selection.

Installation

.. code-block:: shell

$ pip install proxenos[consul] $ # If you'd like Murmur3 support, use: $ pip install proxenos[consul,murmur]

Configuration

Proxenos can be configured through environment variables.

• PROXENOS_MMH_SEED (int): The seed used for MurMur3 hashes.
• PROXENOS_MMH_OPTIMIZE (str): Set to x64 or auto.
• PROXENOS_PRF (str): The default hashing method to use. Defaults to siphash. Can be set to one of md5, sha1, sha224, sha256, sha384, sha512, mmh_32, mmh_64, mmh_128, or siphash.
• PROXENOS_SIPHASH_KEY (str): The 128-bit SipHash key. A default key is provided, but users are advised to generate their own.

Notes

proxenos uses Python's PRNG for calculating the weight of nodes in a cluster, rather than using a linear congruential generator (LCG_) as described in the original paper on Rendezvous hashing__. Seeded weights generated are limited to sys.maxsize, which means the resulting weights will differ depending on the platform architecture.

.. _LCG: https://en.wikipedia.org/wiki/Linear_congruential_generator .. _thaler_ravishankar_1996: http://www.eecs.umich.edu/techreports/cse/96/CSE-TR-316-96.pdf

__ thaler_ravishankar_1996_

Similar projects

• clandestined <https://github.com/ewdurbin/clandestined-python>_
• nikhilgarg28/rendezvous <https://github.com/nikhilgarg28/rendezvous>_