runtime

type Container ¶

type Container struct {
	ID      string
	Name    string
	State   string // running, exited, paused, ...
	Labels  map[string]string
	Mounts  []Mount
	Project string // com.docker.compose.project, empty if not a compose service
	Service string // com.docker.compose.service, empty if not a compose service
}

Container is the normalized view of a container across runtimes.

type DockerRuntime ¶

type DockerRuntime struct {
	// contains filtered or unexported fields
}

DockerRuntime is the Docker adapter for Runtime. It talks to the Docker Engine API over the socket Ballast mounts read-only, using the request and mapping machinery in engine.go that it shares with PodmanRuntime.

The client is created lazily on first use and cached, so constructing a DockerRuntime never touches the socket: nothing fails until a method that actually needs the daemon is called.

func NewDocker(socket string) *DockerRuntime

func (e DockerRuntime) Close() error

func (e DockerRuntime) Exec(ctx context.Context, id string, spec ExecSpec) (*ExecHandle, error)

func (e DockerRuntime) Inspect(ctx context.Context, id string) (Container, error)

func (e DockerRuntime) List(ctx context.Context) ([]Container, error)

func (e DockerRuntime) Start(ctx context.Context, id string) error

func (e DockerRuntime) Stop(ctx context.Context, id string, timeoutSeconds int) error

func (e DockerRuntime) Watch(ctx context.Context) (<-chan Event, <-chan error)

type Event ¶

type Event struct {
	Type   EventType
	ID     string
	Name   string
	Labels map[string]string
}

Event is a single lifecycle change on the socket.

type EventType ¶

type EventType string

EventType is a container lifecycle transition.

const (
	EventStart   EventType = "start"
	EventStop    EventType = "stop"
	EventDie     EventType = "die"
	EventDestroy EventType = "destroy"
)

type ExecHandle ¶

type ExecHandle struct {
	Stdout io.Reader
	Wait   func() (exitCode int, err error)
}

ExecHandle is a running exec. The caller reads Stdout to completion, then calls Wait to learn the exit code. Stderr is captured separately for logging.

type ExecSpec ¶

type ExecSpec struct {
	Cmd  []string
	User string // empty means the container's default user
}

ExecSpec describes a command to run inside a container.

type Mount ¶

type Mount struct {
	Type        MountType
	Name        string // named-volume name, empty for binds and tmpfs
	Source      string // host-side path, empty for tmpfs
	Destination string // container-side path
	ReadOnly    bool
}

Mount is one filesystem mount attached to a container.

type MountType ¶

type MountType string

MountType distinguishes the kinds of mount Ballast cares about.

const (
	MountVolume MountType = "volume"
	MountBind   MountType = "bind"
	MountTmpfs  MountType = "tmpfs"
)

type PodmanRuntime ¶

type PodmanRuntime struct {
	// contains filtered or unexported fields
}

PodmanRuntime is the Podman adapter for Runtime. Podman's REST API includes a Docker-compatible compat layer (documented against the Docker v1.40 API) on the same socket as its native libpod API, so PodmanRuntime talks to it with the exact request and mapping machinery DockerRuntime uses, in engine.go; the two adapters differ only in their default socket path and in how compose project/service identity is read off a container's labels.

The client is created lazily on first use and cached, so constructing a PodmanRuntime never touches the socket: nothing fails until a method that actually needs the daemon is called.

func NewPodman(socket string) *PodmanRuntime

func (e PodmanRuntime) Close() error

func (e PodmanRuntime) Exec(ctx context.Context, id string, spec ExecSpec) (*ExecHandle, error)

func (e PodmanRuntime) Inspect(ctx context.Context, id string) (Container, error)

func (e PodmanRuntime) List(ctx context.Context) ([]Container, error)

func (e PodmanRuntime) Start(ctx context.Context, id string) error

func (e PodmanRuntime) Stop(ctx context.Context, id string, timeoutSeconds int) error

func (e PodmanRuntime) Watch(ctx context.Context) (<-chan Event, <-chan error)

type Runtime ¶

type Runtime interface {
	// List returns every container the runtime knows about, running or not.
	List(ctx context.Context) ([]Container, error)

	// Inspect returns a single container by ID or name.
	Inspect(ctx context.Context, id string) (Container, error)

	// Watch streams lifecycle events until ctx is cancelled. The error channel
	// carries a terminal error and is then closed alongside the event channel.
	Watch(ctx context.Context) (<-chan Event, <-chan error)

	// Exec runs a command inside a running container and returns a handle whose
	// Stdout the caller reads (for stream backups it is piped straight into the
	// engine's stdin) before calling Wait for the exit code.
	Exec(ctx context.Context, id string, spec ExecSpec) (*ExecHandle, error)

	// Stop stops a running container, waiting up to timeoutSeconds before a kill.
	Stop(ctx context.Context, id string, timeoutSeconds int) error

	// Start starts a stopped container.
	Start(ctx context.Context, id string) error

	// Close releases the underlying client.
	Close() error
}

Runtime is a container runtime Ballast can drive. Implementations must be safe for concurrent use by multiple goroutines.