Implement a simple engine server that receives StartEngine commands

[thrau]

To enable decentralized control of engines, we need the mediator to send StartEngine commands to other nodes, rather than starting the engines on the host which the mediator runs on. To that end, we should create a small HTTP server application that wraps the StartEngine command of the runtime

CogStream/mediator/pkg/runtime/runtime_plugin.go

Line 155 in 1edfc6b

func (p *pluginEngineRuntime) StartEngine(engine *engines.EngineDescriptor, spec messages.OperationSpec) (*engines.RunningEngine, error) {

basically the mediator has a controller/worker architecture, where a client requesting an engine talks to the controller, and the controller talks to the workers that spawn engines.

[thrau]

related to 33, since we want to start python engines (emotion detection) on the engine server host

• Mediator should be able to start python engines #33

[thrau]

actually, just having the controller being a websocket proxy that manages several mediator instances may be easier. since the mediator has a bunch of logic to find/control engines that exist locally on the file system.

[thrau]

taking this :-)