Golang Connection.Agent方法代码示例

// uninstallerManifold defines a simple start function which retrieves
// some dependencies, checks if the machine is dead and causes the
// agent to uninstall itself if it is. This doubles up on part of the
// machiner's functionality but the machiner doesn't run until
// upgrades are complete, and the upgrade related workers may not be
// able to make API requests if the machine is dead.
func uninstallerManifold(config uninstallerManifoldConfig) dependency.Manifold {
	return dependency.Manifold{
		Inputs: []string{
			config.AgentName,
			config.APICallerName,
		},
		Start: func(getResource dependency.GetResourceFunc) (worker.Worker, error) {
			if config.WriteUninstallFile == nil {
				return nil, errors.New("WriteUninstallFile not specified")
			}

			// Get the agent.
			var agent agent.Agent
			if err := getResource(config.AgentName, &agent); err != nil {
				return nil, err
			}

			// Grab the tag and ensure that it's for a machine.
			tag, ok := agent.CurrentConfig().Tag().(names.MachineTag)
			if !ok {
				return nil, errors.New("agent's tag is not a machine tag")
			}

			// Get API connection.
			//
			// TODO(mjs) - this should really be a base.APICaller to
			// remove the possibility of the API connection being closed
			// here.
			var apiConn api.Connection
			if err := getResource(config.APICallerName, &apiConn); err != nil {
				return nil, err
			}

			// Check if the machine is dead and set the agent to
			// uninstall if it is.
			//
			// TODO(mjs) - ideally this would be using its own facade.
			machine, err := apiConn.Agent().Entity(tag)
			if err != nil {
				return nil, err
			}
			if machine.Life() == params.Dead {
				if err := config.WriteUninstallFile(); err != nil {
					return nil, errors.Annotate(err, "writing uninstall agent file")
				}
				return nil, worker.ErrTerminateAgent
			}

			// All is well - we're done (no actual worker is actually returned).
			return nil, dependency.ErrUninstall
		},
	}
}

// Manifold returns a dependency manifold that runs an upgrader
// worker, using the resource names defined in the supplied config.
func Manifold(config ManifoldConfig) dependency.Manifold {
	return dependency.Manifold{
		Inputs: []string{
			config.AgentName,
			config.APICallerName,
			config.UpgradeStepsGateName,
		},
		Start: func(getResource dependency.GetResourceFunc) (worker.Worker, error) {
			// Sanity checks
			if config.OpenStateForUpgrade == nil {
				return nil, errors.New("missing OpenStateForUpgrade in config")
			}
			if config.PreUpgradeSteps == nil {
				return nil, errors.New("missing PreUpgradeSteps in config")
			}

			// Get machine agent.
			var agent agent.Agent
			if err := getResource(config.AgentName, &agent); err != nil {
				return nil, err
			}

			// Grab the tag and ensure that it's for a machine.
			tag, ok := agent.CurrentConfig().Tag().(names.MachineTag)
			if !ok {
				return nil, errors.New("agent's tag is not a machine tag")
			}

			// Get API connection.
			var apiConn api.Connection
			if err := getResource(config.APICallerName, &apiConn); err != nil {
				return nil, err
			}

			// Get the machine agent's jobs.
			entity, err := apiConn.Agent().Entity(tag)
			if err != nil {
				return nil, err
			}
			jobs := entity.Jobs()

			// Get machine instance for setting status on.
			machine, err := apiConn.Machiner().Machine(tag)
			if err != nil {
				return nil, err
			}

			// Get upgradesteps completed lock.
			var upgradeStepsLock gate.Lock
			if err := getResource(config.UpgradeStepsGateName, &upgradeStepsLock); err != nil {
				return nil, err
			}

			return NewWorker(
				upgradeStepsLock,
				agent,
				apiConn,
				jobs,
				config.OpenStateForUpgrade,
				config.PreUpgradeSteps,
				machine,
			)
		},
	}
}