bootstrap

Documentation

Index

• Constants
• type Bootstrap
  • func New() (*Bootstrap, error)
  • func (b *Bootstrap) RegisterStarter(starter Starter)
  • func (b *Bootstrap) Start() error
  • func (b *Bootstrap) Wait(gracefulTimeout time.Duration) error
• type ListenFunc
• type Starter

Constants

const (
	// EnvPidFile is the name of the environment variable containing the pid file path
	EnvPidFile = "GITALY_PID_FILE"
	// EnvUpgradesEnabled is an environment variable that when defined gitaly must enable graceful upgrades on SIGHUP
	EnvUpgradesEnabled = "GITALY_UPGRADES_ENABLED"
)

Types

type Bootstrap

type Bootstrap struct {
	// StopAction will be invoked during a graceful stop. It must wait until the shutdown is completed
	StopAction func()
	// contains filtered or unexported fields
}

Bootstrap handles graceful upgrades

func New

func New() (*Bootstrap, error)

New performs tableflip initialization

pidFile is optional, if provided it will always contain the current process PID
upgradesEnabled controls the upgrade process on SIGHUP signal

first boot: * gitaly starts as usual, we will refer to it as p1 * New will build a tableflip.Upgrader, we will refer to it as upg * sockets and files must be opened with upg.Fds * p1 will trap SIGHUP and invoke upg.Upgrade() * when ready to accept incoming connections p1 will call upg.Ready() * upg.Exit() channel will be closed when an upgrades completed successfully and the process must terminate

graceful upgrade:

• user replaces gitaly binary and/or config file
• user sends SIGHUP to p1
• p1 will fork and exec the new gitaly, we will refer to it as p2
• from now on p1 will ignore other SIGHUP
• if p2 terminates with a non-zero exit code, SIGHUP handling will be restored
• p2 will follow the "first boot" sequence but upg.Fds will provide sockets and files from p1, when available
• when p2 invokes upg.Ready() all the shared file descriptors not claimed by p2 will be closed
• upg.Exit() channel in p1 will be closed now and p1 can gracefully terminate already accepted connections
• upgrades cannot starts again if p1 and p2 are both running, an hard termination should be scheduled to overcome freezes during a graceful shutdown

gitaly-wrapper is supposed to set EnvUpgradesEnabled in order to enable graceful upgrades

func (*Bootstrap) RegisterStarter

func (b *Bootstrap) RegisterStarter(starter Starter)

RegisterStarter adds a new starter

func (*Bootstrap) Start

func (b *Bootstrap) Start() error

Start will invoke all the registered starters and wait asynchronously for runtime errors in case a Starter fails then the error is returned and the function is aborted

func (*Bootstrap) Wait

func (b *Bootstrap) Wait(gracefulTimeout time.Duration) error

Wait will signal process readiness to the parent and than wait for an exit condition SIGTERM, SIGINT and a runtime error will trigger an immediate shutdown in case of an upgrade there will be a grace period to complete the ongoing requests

type ListenFunc

type ListenFunc func(net, addr string) (net.Listener, error)

ListenFunc is a net.Listener factory

type Starter

type Starter func(ListenFunc, chan<- error) error

Starter is function to initialize a net.Listener it receives a ListenFunc to be used for net.Listener creation and a chan<- error to signal runtime errors It must serve incoming connections asynchronously and signal errors on the channel the return value is for setup errors