PyBoss

Manage your app's configurations with PyBoss! you can define several sources for aquiring configurations:

• JsonFileSource
• YamlFileSource
• RedisSource
• MongodbSource
• EnvironmentSource
• Your custom config source...

pass all of your sources to Boss then he'll take care of them.

you can partially overwrite config value by defining sources

TODO:

• mutual lock for read and write
• CLI for source check
• unit tests

Quick Start

first of all, you need to define your config sources. then pass them as a list to Boss. the order of the list matter, as it expresses which source should come on top of witch one:

from pymongo import MongoClient
from redis import Redis

from pyboss.boss import Boss
from pyboss.source import JsonFileSource, YamlFileSource, RedisSource, EnvironmentSource, MongodbSource

json_source = JsonFileSource(file_path='test_data/dict_and_array.json')
yaml_source = YamlFileSource(file_path='test_data/dict_and_array.yml')

redis = Redis()
redis_source = RedisSource(rdb=redis, config_key='Like_SVC')

mongo = MongoClient(connect=False)
mongo_source = MongodbSource(mongo, db_name='cfg', collection_name='twitter')

env_source = EnvironmentSource()

b = Boss([
    json_source,
    yaml_source,
    redis_source,
    mongo_source,
    env_source,
], refresh_interval=120)

when an instance of Boss is created, all of the sources will be evaluated and merged respectively. we use jsonmerge for merging output of each source, on top of result of all previous sources.

print(b.like_svc.host)
print(b.db[1].host)

parameter refresh_interval indicates interval of reload procedure. default to 0 witch means no reload. this feature is intended to be used for having live configs. any failure in further reloads (except first time), will not cause your application exit.

In case of emergency...

assume that you override some configs using MongoDB source. if your MongoDB instance is not available for any reason, you can disable MongodbSource load by setting PYBOSS_NO_MONGODB environment variable. so that you don't need to change any line of code or rebuild. same behaviour for redis, by setting PYBOSS_NO_REDIS

you should pass MongoClient(connect=False), so client does not attempt to connect in advance. otherwise PYBOSS_NO_MONGODB will have no use...

Document schema for MongoDB

{
    "_id": {
        "$oid": "5f4a2856133f34383e3b1000"
    },
    "_version": 1,
    "service_name": "like_svc",
    "port": 4444,
    "database": [
        {"driver": "mongodb"}
    ]
}

the field _version effects which document to load. the highest version is loaded. the type must be int32.

Value schema for Redis

RedisSource(rdb=redis, config_key='Like_SVC') the config_key parameter tell RedisSource witch key to get. other behaviours are just like a json file

Value schema for env

this source is absolutely case sensitive. so boss.lev1.lev2 corresponds to lev1__lev2 in environment. note that all the configs overridden by env are typed as str. you're responsible to type cast. for technical reasons we're not able to detect type at the moment.

MergeStrategy for sources

Strategy for merge result of every source, on top of previous ones, can be specified by JsonSchema and some options. a Merger instance might pass to XSource constructor. for further information, please read this section.