github.com/zzy987/grpc_consistent_hash_balancer

GRPC Consistent Hash Balancer

A demo of a grpc balancer using consistent hash

Features

• Consistent Hash Ring: All servers are abstracted into a hash ring in the picker, implemented in /client/balancer/consistent_hash_picker.

• On-demand Connections Setting up: Different from the default behavior of grpc to set up connections with all servers, I use a trick to make connections set up on-demand, implemented in /client/balancer/consistent_hash_balancer.

• Retry in Interceptor: Unlike the retry example of grpc which implements retry ability with a service config, I implement it in the interceptor, for service config based retry Because retry based on service config will ignore some errors in streaming, implemented in /client/main.

• Connection Survival Management: The balancer will reset a connection to idle when it has not been using for too long, for it seems like grpc will not close any connection unless some network exception happens, implemented in /client/balancer/consistent_hash_balancer.