cluster

type Cluster interface {
	// NewNodes creates nodes and adds them to the cluster. Generally this should return when the nodes are ready to use.
	NewNodes(ctx context.Context, n int) (Nodes, error)

	// Cleanup destroys all cluster nodes and any other state related to the cluster.
	Cleanup(ctx context.Context) error
}

type Fetcher interface {
	// Fetch fetches content from a URL with an HTTP GET and stores the content in the given path on the node.
	Fetch(ctx context.Context, url, path string) error
}

type Node interface {
	StartProc(ctx context.Context, req StartProcRequest) (Process, error)
	SendFile(ctx context.Context, filePath string, Contents io.Reader) error
	ReadFile(ctx context.Context, path string) (io.ReadCloser, error)
	Stop(ctx context.Context) error
	Dial(ctx context.Context, network, address string) (net.Conn, error)
	String() string
}

type Nodes []Node

type Process interface {
	// Wait waits for the process to exit and returns its exit code.
	Wait(context.Context) (*ProcessResult, error)
	// Sends a signal to the process.
	Signal(context.Context, syscall.Signal) error
}

type ProcessResult struct {
	ExitCode int
	TimeMS   int64
}

type StartProcRequest struct {
	Command string
	Args    []string
	// Env is the environment variables of the process, in the form "k=v".
	// If unspecified, the environment variables to use are implementation-defined.
	Env []string
	// WD is the working directory of the process.
	// If unspecified, this is implementation-defined.
	WD string

	// Stdin is a reader which, when specified, is sent to the process's stdin.
	Stdin io.Reader
	// StdinFile is a server-side file which should be read into stdin. If specified, Stdin is ignored.
	StdinFile string

	// Stdout is a writer which, when specified, receives the stdout of the process.
	Stdout io.Writer
	// StdoutFile is a server-side file to which stdout should be written. If specified, Stdout is ignored.
	StdoutFile string

	// Stderr is a writer which, when specified, receives the stderr of the process.
	Stderr io.Writer
	// StderrFile is a server-side file to which stderr should be written. If specified, Stderr is ignored.
	StderrFile string
}