godaemon

README

godaemon

godaemon allows you to easily modify your application, like a web server, to be run in the background. Specify your service, then implement the Daemonizer. After that you only need to call the Start or Stop function depending on your conditions, like calling the cli with specific parameters, and you're done.

It will start the program itself in a detached mode and pass an environment variable to separate the "controlling" part from the "service" part.

Daemonizer

The daemonizer is the tool to start and stop the daemon. You can call the Start or Stop methods to control the service, e.g. using a CLI framework like Cobra, or just simply using os.Args like in the example.

var daemonizer = godaemon.New(godaemon.Options{
    Name:        "service",
    EnvVariable: "DAEMON",
    Service:     service,
})

• Name: The service name. This is required.
• EnvVariable: The name of the environment variable, to control if the program should run the service.
• Service: The function containing the service, which should run in the background.

Service name

The service needs a name. The name will be part of the log and pid file. The name should be build using letters, numbers and underscores, e.g. web_server.

Log file

After the start, the log output is set to a log file. All log outputs will be written to the file.

PID file

The service will write its process id into a file, so that the Daemonizer knows what process to kill when stopping.

Example

In the example folder, a simple web server is implemented. It can be started or stopped using those keywords.

// build the example
go build -o example ./example

// start the service
./example start
// notice that the files "service.log" and "service.pid" are created

// stop the service
./example stop

Documentation

Index

• Constants
• type Daemonizer
  • func New(options Options) *Daemonizer
  • func (d *Daemonizer) IsService() (bool, error)
  • func (d *Daemonizer) Start() error
  • func (d *Daemonizer) Stop() error
• type Options

Constants

const (
	DefaultEnvVariable = "DAEMON"

	PatternServiceName = "^[A-Za-z0-9_]+$"
	PatternEnvVariable = "^[A-Za-z0-9_]+$"
)

Types

type Daemonizer

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

Daemonizer is a structure to control the service. Use the New function to create it.

func New

func New(options Options) *Daemonizer

New creates a Daemonizer.

func (*Daemonizer) IsService

func (d *Daemonizer) IsService() (bool, error)

IsService should be executed at first in your main method. When the program is executed as the service, it executes your service function and then returns true. when the program is executed normally, it returns false, and you should use the Daemonizer to start or stop the service.

func (*Daemonizer) Start

func (d *Daemonizer) Start() error

Start starts your program as background service.

func (*Daemonizer) Stop

func (d *Daemonizer) Stop() error

Stop tries to stop your running service.

type Options

type Options struct {
	Name        string
	EnvVariable string
	Service     func() error
}

Options for running the Daemonizer.