asFollower()

function asFollower(service, leader): AnySkipService

Run a SkipService as a follower in a leader-follower topology.

Instead of running a service on one machine, it can be distributed across multiple in a leader-follower architecture, with one "leader" maintaining the shared computation graph and one or more "followers" across which client-requested resource instances are distributed.

The two kinds of shared collection are obtained differently. Eager collections, named in collections, are mirrored from the leader: the leader maintains them and streams their updates to the follower. Lazy collections cannot be mirrored, since they hold no maintained state to stream; each is instead rebuilt locally by the follower, lazies mapping its shared name to a function which, given the follower's Context, produces the corresponding lazy collection. Together, the two are expected to cover the ResourceInputs of service.

Parameters

Parameter	Type
service	AnySkipService
leader	{ collections: string[]; lazies: {}; leader: { control_port: number; host: string; streaming_port: number; }; }
leader.collections	string[]
leader.lazies?	{}
leader.leader	{ control_port: number; host: string; streaming_port: number; }
leader.leader.control_port	number
leader.leader.host	string
leader.leader.streaming_port	number

Returns

AnySkipService

The follower component to run service in such a configuration.