package signal

import "github.com/docker/cli/components/engine/pkg/signal"

Package signal provides helper functions for dealing with signals across various operating systems.

Index ¶

• Constants
• Variables
• func CatchAll(sigc chan os.Signal)
• func DumpStacks(dir string) (string, error)
• func ParseSignal(rawSignal string) (syscall.Signal, error)
• func StopCatch(sigc chan os.Signal)
• func Trap(cleanup func(), logger interface { Info(args ...interface{}) })
• func ValidSignalForPlatform(sig syscall.Signal) bool

Constants ¶

const (
	SIGCHLD  = syscall.Signal(0xff)
	SIGWINCH = syscall.Signal(0xff)
	SIGPIPE  = syscall.Signal(0xff)
	// DefaultStopSignal is the syscall signal used to stop a container in windows systems.
	DefaultStopSignal = "15"
)

Signals used in cli/command (no windows equivalent, use invalid signals so they don't get handled)

Variables ¶

var SignalMap = map[string]syscall.Signal{
	"KILL": syscall.SIGKILL,
	"TERM": syscall.SIGTERM,
}

SignalMap is a map of "supported" signals. As per the comment in GOLang's ztypes_windows.go: "More invented values for signals". Windows doesn't really support signals in any way, shape or form that Unix does.

We have these so that docker kill can be used to gracefully (TERM) and forcibly (KILL) terminate a container on Windows.

Functions ¶

func CatchAll ¶

func CatchAll(sigc chan os.Signal)

CatchAll catches all signals and relays them to the specified channel.

func DumpStacks ¶

func DumpStacks(dir string) (string, error)

DumpStacks appends the runtime stack into file in dir and returns full path to that file.

func ParseSignal ¶

func ParseSignal(rawSignal string) (syscall.Signal, error)

ParseSignal translates a string to a valid syscall signal. It returns an error if the signal map doesn't include the given signal.

func StopCatch ¶

func StopCatch(sigc chan os.Signal)

StopCatch stops catching the signals and closes the specified channel.

func Trap ¶

func Trap(cleanup func(), logger interface {
	Info(args ...interface{})
})

Trap sets up a simplified signal "trap", appropriate for common behavior expected from a vanilla unix command-line tool in general (and the Docker engine in particular).

• If SIGINT or SIGTERM are received, `cleanup` is called, then the process is terminated.
• If SIGINT or SIGTERM are received 3 times before cleanup is complete, then cleanup is skipped and the process is terminated immediately (allows force quit of stuck daemon)
• A SIGQUIT always causes an exit without cleanup, with a goroutine dump preceding exit.
• Ignore SIGPIPE events. These are generated by systemd when journald is restarted while the docker daemon is not restarted and also running under systemd. Fixes https://github.com/docker/docker/issues/19728

func ValidSignalForPlatform ¶

func ValidSignalForPlatform(sig syscall.Signal) bool

ValidSignalForPlatform returns true if a signal is valid on the platform

Source Files ¶

signal.go signal_windows.go trap.go

Directories ¶