Documentation
¶
Index ¶
- Constants
- Variables
- func DaemonReload(ctx context.Context) error
- func DisableService(ctx context.Context, name string) error
- func DisableSwap() error
- func EnableService(ctx context.Context, name string) error
- func EnableSwap() error
- func GoDump()
- func IsServiceEnabled(ctx context.Context, name string) (bool, error)
- func IsServiceRunning(ctx context.Context, name string) (bool, error)
- func MaskUnit(ctx context.Context, name string) error
- func NewSignalHandler() (SignalHandler, ShutdownFunc)
- func RestartService(ctx context.Context, name string) error
- func StopService(ctx context.Context, name string) error
- func SwapOff(path string) error
- func SwapOffAll() error
- func SwapOn(path string, flags int) error
- func SwapOnAll() error
- func UnmaskUnit(ctx context.Context, name string) error
- type ShutdownFunc
- type SignalCallback
- type SignalHandler
Constants ¶
const ( SWAP_EX_ENOMEM = 2 // swapoff failed due to OOM SWAP_EX_FAILURE = 4 // swapoff failed due to other reason SWAP_EX_USAGE = 16 // usage/permissions/syntax error SWAPON_FLAG_DISCARD = 0x10000 // enable discard for swap SWAPON_FLAG_DISCARD_ONCE = 0x20000 // discard swap area at swapon-time SWAPON_FLAG_DISCARD_PAGES = 0x40000 // discard page-clusters after use ETC_LOCATION = "/etc" FSTAB_LOCATION = "/etc/fstab" PROC_SWAPS_LOCATION = "/proc/swaps" DISK_BY_UUID_LOCATION = "/dev/disk/by-uuid" DISK_BY_LABEL_LOCATION = "/dev/disk/by-label" SwapCommentPrefix = "#" // prefix used when commenting out swap lines in fstab )
SwapOff exit code: https://github.com/util-linux/util-linux/blob/master/sys-utils/swapoff.c#L43-L49 SwapOn Flags: https://github.com/util-linux/util-linux/blob/57d59a5cd5ba6c0b32cae27f5ce48241274f6e6e/sys-utils/swapon.c#L50-L63
Variables ¶
var ( ErrNamespace = errorx.NewNamespace("os") SwapErrTrait = errorx.RegisterTrait("swap_error") FileErrTrait = errorx.RegisterTrait("file_error") SystemdErrTrait = errorx.RegisterTrait("systemd_error") ErrSwapOutOfMemory = ErrNamespace.NewType("out_of_memory", SwapErrTrait) ErrInvalidSwapFile = ErrNamespace.NewType("invalid_swap_file", SwapErrTrait) ErrSwapUnknownSyscall = ErrNamespace.NewType("unknown_syscall", SwapErrTrait) ErrNonSyscall = ErrNamespace.NewType("non_syscall", SwapErrTrait) ErrSwapNotSuperUser = ErrNamespace.NewType("not_super_user", SwapErrTrait) ErrFileInaccessible = ErrNamespace.NewType("file_inaccessible", FileErrTrait) ErrSwapDeviceNotFound = ErrNamespace.NewType("device_not_found", SwapErrTrait) ErrFileRead = ErrNamespace.NewType("file_read_error", FileErrTrait) ErrFileWrite = ErrNamespace.NewType("file_write_error", FileErrTrait) ErrSystemdConnection = ErrNamespace.NewType("systemd_connection_error", SystemdErrTrait) ErrSystemdOperation = ErrNamespace.NewType("systemd_operation_error", SystemdErrTrait) PathProperty = errorx.RegisterProperty("path") SysErrorCodeProperty = errorx.RegisterProperty("sys_error_code") )
Functions ¶
func DaemonReload ¶
DaemonReload reloads the systemd manager configuration. It is equivalent to running "systemctl daemon-reload".
func DisableService ¶
DisableService disables the specified service. It is equivalent to running "systemctl disable <service>". The service name can be provided with or without the .service suffix.
func DisableSwap ¶
func DisableSwap() error
DisableSwap disables swap completely on the system. It performs the following steps: 1. Masks systemd swap units to prevent auto-activation 2. Turns off all active swap (swapoff -a) 3. Comments out swap entries in /etc/fstab to prevent reactivation on boot 4. Reloads systemd daemon
This ensures swap stays disabled even on systemd-based systems that auto-detect swap partitions by their filesystem signature.
func EnableService ¶
EnableService enables the specified service. It is equivalent to running "systemctl enable <service>". The service name can be provided with or without the .service suffix.
func EnableSwap ¶
func EnableSwap() error
EnableSwap re-enables swap on the system. It performs the following steps: 1. Uncomments swap entries in /etc/fstab 2. Unmasks systemd swap units to allow auto-activation 3. Reloads systemd daemon 4. Activates all swap entries from /etc/fstab (swapon -a)
func GoDump ¶
func GoDump()
GoDump dumps output of goroutine dump.
In order to have this in the output, one need to send a signal (e.g. SIGQUIT) signal to the process using kill: `kill -SIGQUIT <pid>` and register a callback for that OS signal(i.e. SIGQUIT) with the SignalHandler.
Example: assuming `handler` is an instance of SignalHandler and we are adding SIGQUIT handler for a systemd daemon.
handler.Register(syscall.SIGQUIT, func(os.Signal) {
nmtos.GoDump()
logger.Debug("Received SIGQUIT. " +
"Check Go routine dump in logs using 'sudo journalctl --unit <daemon-name> --follow'." +
"Continuing daemon operation as before...")
})
func IsServiceEnabled ¶
IsServiceEnabled checks if the specified service is enabled. The service name can be provided with or without the .service suffix.
func IsServiceRunning ¶
IsServiceRunning checks if the specified service is running. The service name can be provided with or without the .service suffix.
func MaskUnit ¶
MaskUnit masks the specified unit, preventing systemd from activating it. It is equivalent to running "systemctl mask <unit>". The unit name can be provided with or without the appropriate suffix (.service, .swap, etc.).
func NewSignalHandler ¶
func NewSignalHandler() (SignalHandler, ShutdownFunc)
NewSignalHandler returns an instance of SignalHandler. Caller is expected call the returned ShutdownFunc to stop listening for all the events.
func RestartService ¶
RestartService starts the specified service. This function waits until the service is fully started. It is equivalent to running "systemctl start <service>". The service name can be provided with or without the .service suffix.
func StopService ¶
StopService stops the specified service. This function waits until the service is fully stopped. It is equivalent to running "systemctl stop <service>". The service name can be provided with or without the .service suffix.
func SwapOff ¶
SwapOff performs swapoff for a single path On success, it returns SWAP_EX_OK and nil error. On error, it returns a non-zero status code and a wrapped errorx error with details.
func SwapOffAll ¶
func SwapOffAll() error
SwapOffAll attempts to disable all swap devices/files on the system based on /proc/swaps and /etc/fstab.
func UnmaskUnit ¶
UnmaskUnit unmasks the specified unit, allowing systemd to activate it again. It is equivalent to running "systemctl unmask <unit>". The unit name can be provided with or without the appropriate suffix (.service, .swap, etc.).
Types ¶
type ShutdownFunc ¶
type ShutdownFunc func()
ShutdownFunc defines a cleanup function to be called on exit of the process
type SignalCallback ¶
SignalCallback defines the OS signal callback function
type SignalHandler ¶
type SignalHandler interface {
// Register registers a callback function for the given os.Signal.
//
// It only allows a single callback function to be registered for an OS signal.
// It returns error if a callback function already exists.
//
// If the handler has been shutdown already, it will return error for any new registrations.
Register(sig os.Signal, cb SignalCallback) error
// Unregister unregisters callback function for the given os.Signal.
Unregister(sig os.Signal)
// IsActive returns true if is active and able to process signals.
//
// If it is not active, attempting to register a callback will return error.
IsActive() bool
// HasCallback returns true if a callback is already registered for the given OS signal
HasCallback(sig os.Signal) bool
}
SignalHandler exposes signal handling functionalities It allows only one callback to be registered for an OS signal.
Source Files