Added domain and polling_interval in config and env vars for worker tasks

[coderabhigupta]

Worker Configuration

Using Config File

Added support to read an worker.ini file in the root directory of the worker code that allows for setting default values for task domain and polling intervals for workers. Config file will always override constructor params. These properties are expected to be in the form of:

[task_definition_name]
domain = <domain>
polling_interval = <polling-interval-in-ms>

[DEFAULT]
domain = <domain>
polling_interval = <polling-interval-in-ms>

Examples:

[DEFAULT]
domain = nice
polling_interval = 2000

[python_annotated_task_1]
domain = cool
polling_interval = 500

[python_annotated_task_2]
domain = hot
polling_interval = 300

Using Environment Variables

Workers can also be configured at run time by using environment variables which override configuration files as well. Environment variables will always override Config file. Upper case ENV vars are also supported but task definition names will be case sensitive.

Examples:

CONDUCTOR_WORKER_DOMAIN=nice
conductor_worker_polling_interval=2000
conductor_worker_python_annotated_task_1_domain=cool
CONDUCTOR_WORKER_python_annotated_task_1_POLLING_INTERVAL=500
CONDUCTOR_WORKER_python_annotated_task_2_DOMAIN=hot
conductor_worker_python_annotated_task_2_polling_interval=300