ods (Oystr - Discovery Service)

Ods is a discovery/registry service that allows us to keep track of dynamic services added to our infrastructure and their status through regular health checks. e.g.: dynamic proxy servers.

Requirements

• Python3.7+
• PIP3

Installation

To install, we basically run pip along with requirements.txt:

$ pip install -r requirements.txt

Running

Configure a .env file with the following data:

[postgres]
database=discovery
host=<DATABASE_HOSTNAME>
username=<USERNAME>
password=<PASSWORD>

[load_balancer]
lb_address=<LOAD_BALANCER_ADDRESS>

In order to run the service, just type:

$ python3 main.py

Default behaviour/configuration

By default, we run a health check task every 30 seconds and update the service status accordingly.

A newly registered service starts as unknown. After the first successful health check, it's then updated to running, otherwise it's updated to pending. After 2 failures, the status is updated to failing and after the third failure, the status is updated to disabled.

Every 15 minutes we run a cleanup tasks that removes all services marked as disabled.

Routes

GET    /services                             Get a list of all services with meta information (last_health_check, status, registered_at...).
POST   /services                             Add a new service. e.g.: {"service_id": "<ID>", "host": "<IP_ADDRESS>", "port": 8888}
DELETE /services/<service_id>/<host>/<port>  Delete a service.

TODO

• Document routes;
• Avoid duplicated services + hosts + ports;
• Dockerize;
• Use GUnicorn;
• Create a discovery.conf file;
• Log to /var/log/ods.log.