Provides an integration for gruf Ruby gRPC framework, allowing testing various outbound Gruf::Client calls on a percentage-basis, letting you balance requests between multiple clients for testing new services, code paths, or networking operations.

gem 'gruf-balancer'

Instead of creating a normal Gruf::Client, simply add clients to a Gruf::Balancer::Client, via passing in a percentage of requests and client options (similarly to how you'd create Gruf::Client objects).

client = Gruf::Balancer::Client.new(service: MyService)
client.add_client(percentage: 60, options: { hostname: '127.0.0.1:8000' })
client.add_client(percentage: 40, options: { hostname: '127.0.0.1:8001' })
# @type [Gruf::Response] resp
resp = client.call(:GetThing, id: 123)

This uses a weighted random sampling algorithm under the hood to balance the requests to the method on the defined percentage weights. In the example above, 60% of requests would go to our service on port 8000, and 40% on port 8001.

Gruf::Balancer::Client acts similarly to a Gruf::Client, in terms of its call method signature. It maintains a thread-safe pool of clients. Note, similarly to gRPC core, that clients are not fork-safe; please instantiate any balanced client pools after forking.

Some use cases for gruf-balancer can be:

• Testing a new application service that serves the same gRPC Service, but on a different hostname
• Testing different hostnames, routing rules, network infrastructure, or service meshes via different hostnames
• Testing new client options, such as timeouts, credentials, channels, or channel arguments
• Testing new client interceptors, since they are configured per-client

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