Emcee

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import Dispatch
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import DistWorkerModels
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import Foundation
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import EmceeLogging
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import QueueModels
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import RESTInterfaces
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import RESTMethods
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import RESTServer
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import WorkerAlivenessProvider
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public final class KickstartWorkerEndpoint: RESTEndpoint {
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    private let onDemandWorkerStarter: OnDemandWorkerStarter
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    private let workerAlivenessProvider: WorkerAlivenessProvider
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    private let workerConfigurations: WorkerConfigurations
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    public let path: RESTPath = KickstartWorkerRESTMethod()
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    public let requestIndicatesActivity = false
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    public init(
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        onDemandWorkerStarter: OnDemandWorkerStarter,
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        workerAlivenessProvider: WorkerAlivenessProvider,
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        workerConfigurations: WorkerConfigurations
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    ) {
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        self.onDemandWorkerStarter = onDemandWorkerStarter
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        self.workerAlivenessProvider = workerAlivenessProvider
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        self.workerConfigurations = workerConfigurations
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    }
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    public enum KickstartError: Error, CustomStringConvertible {
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        case isAlive(WorkerId)
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        public var description: String {
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            switch self {
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            case .isAlive(let workerId):
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                return "Can't kickstart \(workerId) because it is alive"
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            }
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        }
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    }
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    public func handle(payload: KickstartWorkerPayload) throws -> KickstartWorkerResponse {
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        guard workerConfigurations.workerConfiguration(workerId: payload.workerId) != nil else {
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            throw WorkerConfigurationError.missingWorkerConfiguration(workerId: payload.workerId)
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        }
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        let workerAliveness = workerAlivenessProvider.alivenessForWorker(workerId: payload.workerId)
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        guard !workerAliveness.registered || workerAliveness.silent else {
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            throw KickstartError.isAlive(payload.workerId)
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        }
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        try onDemandWorkerStarter.start(workerId: payload.workerId)
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        return KickstartWorkerResponse(workerId: payload.workerId)
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    }
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}
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