#discovery

This service provides a REST interface for querying for the list of hosts that belong to a given service in microservice infrastructure. Host information is written to and read from Dynamo. This project relies on the following libraries:

• Flask (web-framework)
• Flask-Cache (for caching and reusing results for GET requests)
• Pynamodb (for reading/writing DynamoDB data)

##API ###GET /v1/registration/:service

• Returns the list of hosts for :service

###GET /v1/registration/repo/:service_repo_name

• Returns the list of hosts for :service_repo_name (queries a Dynamodb GSI for this info)

###POST /v1/registration/:service

• Used to register a host with a service. The list of required parameters is as follows:
• ip (the ip address of the host)
• port (the port on which the host expects connections)
• revision (the sha of the github revision the service is currently running)
• tags (a JSON dictionary with the following fields)
  • az (Required: the AWS availability zone that the host is running in)
  • region (Required: the AWS region that the host is running in)
  • instance_id (Required: the AWS instance_id of the host)
  • canary (Optional: boolean string set to "true" if the host is a canary)
  • load_balancing_weight (Optional: may be used for load balancing)

###DELETE /v1/registration/:service/:ip_address

• Deletes the host for the given :service and :ip_address

###POST /v1/loadbalancing/:service/:ip_address

• Used to update the weight of hosts for load balancing purposes.
• :ip_address is optional. If not given, all hosts for the given service will have their weights updated.
• The list of required parameters is as follows:
• load_balancing_weight (an integer between 1 and 100)

##Main Classes

• app/routes/api.py
• defines the HTTP routes for service registration
• app/resources/api.py
• the entry point for service registration GETs and POSTs
• app/services/host.py
• contains the business logic (e.g. caching, input validation, etc) for service registration GETS and POSTs
• app/models/host.py
• The pynamo model for service registration information for a host

##Unit Testing To run all unit tests, run make test_unit.