gapi

type CliInfo struct {
	// CliContext is the struct that is used to transfer in user input.
	CliContext *cli.Context
	// Fs is the filesystem the Cli method should copy data into. It usually
	// copies *from* the local filesystem using standard io functionality.
	Fs    engine.Fs
	Debug bool
	Logf  func(format string, v ...interface{})
}

type Data struct {
	Program       string // name of the originating program
	Hostname      string // uuid for the host, required for GAPI
	World         engine.World
	Noop          bool
	NoStreamWatch bool
	Prefix        string
	Debug         bool
	Logf          func(format string, v ...interface{})
}

type Deploy struct {
	ID   uint64
	Name string // lang, puppet, yaml, etc...
	//Sync bool // wait for everyone to close previous GAPI before switching
	Noop bool
	Sema int // sema override
	GAPI GAPI
}

type GAPI interface {
	// CliFlags is passed a Command constant specifying which command it is
	// requesting the flags for. If an invalid or unsupported command is
	// passed in, simply return an empty list. Similarly, it is not required
	// to ever return any flags, and the GAPI may always return an empty
	// list.
	CliFlags(string) []cli.Flag

	// Cli is run on each GAPI to give it a chance to decide if it wants to
	// activate, and if it does, then it will return a deploy struct. During
	// this time, it uses the CliInfo struct as useful information to decide
	// what to do.
	Cli(*CliInfo) (*Deploy, error)

	// Init initializes the GAPI and passes in some useful data.
	Init(*Data) error

	// Graph returns the most recent pgraph. This is called by the engine on
	// every event from Next().
	Graph() (*pgraph.Graph, error)

	// Next returns a stream of switch events. The engine will run Graph()
	// to build a new graph after every Next event.
	Next() chan Next

	// Close shuts down the GAPI. It asks the GAPI to close, and must cause
	// Next() to unblock even if is currently blocked and waiting to send a
	// new event.
	Close() error
}

type GetInfo struct {
	// CliContext is the struct that is used to transfer in user input.
	CliContext *cli.Context

	Noop   bool
	Sema   int
	Update bool

	Debug bool
	Logf  func(format string, v ...interface{})
}

type GettableGAPI interface {
	GAPI // the base interface must be implemented

	// Get runs the get/download method.
	Get(*GetInfo) error
}

type Next struct {
	// FIXME: the Fast pause parameter should eventually get replaced with a
	// "SwitchMethod" parameter or similar that instead lets the implementer
	// choose between fast pause, slow pause, and interrupt. Interrupt could
	// be a future extension to the Resource API that lets an Interrupt() be
	// called if we want to exit immediately from the CheckApply part of the
	// resource for some reason. For now we'll keep this simple with a bool.
	Fast bool  // run a fast pause to switch?
	Exit bool  // should we cause the program to exit? (specify err or not)
	Err  error // if something goes wrong (use with or without exit!)
}