func()

in ecs-init/engine/engine.go [108:160]

• 39 lines of code
• 11 McCabe index (conditional complexity)

func (e *Engine) PreStart() error {
	// setup gpu if necessary
	err := e.PreStartGPU()
	if err != nil {
		return err
	}
	// Enable use of loopback addresses for local routing purposes
	err = e.loopbackRouting.Enable()
	if err != nil {
		return engineError("could not enable loopback routing", err)
	}
	// Disable ipv6 router advertisements
	err = e.ipv6RouterAdvertisements.Disable()
	if err != nil {
		return engineError("could not disable ipv6 router advertisements", err)
	}
	// Add the rerouting netfilter rule for credentials endpoint
	err = e.credentialsProxyRoute.Create()
	if err != nil {
		return engineError("could not create route to the credentials proxy", err)
	}

	docker, err := getDockerClient()
	if err != nil {
		return dockerError(err)
	}
	imageLoaded, err := docker.IsAgentImageLoaded()
	if err != nil {
		return engineError("could not check Docker for Agent image presence", err)
	}

	switch e.downloader.AgentCacheStatus() {
	// Uncached, go get the Agent.
	case cache.StatusUncached:
		return e.downloadAndLoadCache(docker)

	// The Agent is cached, and mandates a reload regardless of the
	// already loaded image.
	case cache.StatusReloadNeeded:
		return e.load(docker, e.downloader.LoadCachedAgent)

	// Agent is cached, respect the already loaded Agent.
	case cache.StatusCached:
		if imageLoaded {
			return nil
		}
		return e.load(docker, e.downloader.LoadCachedAgent)

	// There shouldn't be unhandled cache states.
	default:
		return errors.New("could not handle cache state")
	}
}