Clever/discovery-python

Name: discovery-python

Owner: Clever

Description: Programmatically find service endpoints (i.e. discovery-go for python)

Created: 2016-03-08 23:00:57.0

Updated: 2017-01-10 02:49:53.0

Pushed: 2018-01-11 18:28:30.0

Homepage: null

Size: 12

Language: Python

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README

discovery-python

This library programmatically finds endpoints for dependencies. Similar to discovery-go and disocvery-node.

See Service Discovery for more details.

Installation

pip

Assuming discovery v0.1.0 is being installed:

install git+https://github.com/Clever/discovery-python.git@v0.1.0

setup.py

 setuptools import setup

suming discovery v0.1.0 is being installed:
p(

# ...

install_requires=['discovery==0.1.0'],
dependency_links=[
  'https://github.com/Clever/discovery-python/tarball/v0.1.0#egg=discovery-0.1.0'
],

# ...

Usage

rt discovery


stoked_url = discovery.url('stoked', 'thrift')

stoked_host_and_port = discovery.host_port('stoked', 'thrift')

stoked_host = discovery.host('stoked', 'thrift')

stoked_port = discovery.port('stoked', 'thrift')

pt discovery.MissingEnvironmentVariableError as e:
print 'ERROR: Stoked discovery failed: {}.'.format(e)

Development

Publishing a new version

1. Bump the version in the VERSION file and update the changelog in CHANGES.md.

2. Merge your changes into master.

3. Checkout master

4. Run the publish script:

   blish.sh
   

Implementation Details

Currently, discovery-{go,node,python} looks for environment variables with the following format:

ICE_{SERVICE_NAME}_{EXPOSE_NAME}_{PROTO,HOST,PORT}

These environment variables are autogenerated by our deployment tooling. Three env-vars are created for each app listed in the dependencies section of caller's launch yaml.

For example, if an app lists district-authorizations as a dependency, fab and catapult will generate this env-vars triplet:

ICE_DISTRICT_AUTHORIZATIONS_HTTP_PROTO = "http"
ICE_DISTRICT_AUTHORIZATIONS_HTTP_HOST = "district-authorizations.ops.clever.com"
ICE_DISTRICT_AUTHORIZATIONS_HTTP_PORT = "80"