daemon

README

Daemon Module

A service lifecycle management module integrated with Uber Fx, providing ready state and health status tracking for your application.

Features

• Uber Fx dependency injection integration
• Ready state tracking
• Health status management
• Automatic lifecycle management

Installation

go get github.com/weedbox/common-modules/daemon

Quick Start

Basic Usage

Important: The daemon module should be placed at the end of all other modules. When OnStart is called, it sets isReady to true. Placing it last ensures that all other modules have completed their initialization before the service is marked as ready.

package main

import (
    "github.com/weedbox/common-modules/daemon"
    "github.com/weedbox/common-modules/http_server"
    "github.com/weedbox/common-modules/logger"
    "github.com/weedbox/common-modules/postgres_connector"
    "go.uber.org/fx"
)

func main() {
    fx.New(
        // Infrastructure modules
        logger.Module(),
        postgres_connector.Module("database"),
        http_server.Module("http_server"),

        // Application modules
        // ...

        // Daemon should be last - marks service as ready after all modules are initialized
        daemon.Module("daemon"),
    ).Run()
}

Checking Service Status

package myservice

import (
    "github.com/weedbox/common-modules/daemon"
    "go.uber.org/fx"
)

type Params struct {
    fx.In

    Daemon *daemon.Daemon
}

func (s *Service) CheckStatus(p Params) {
    // Check if service is ready
    if p.Daemon.Ready() {
        // Service is ready to accept requests
    }

    // Check health status
    status := p.Daemon.GetHealthStatus()
    if status == daemon.HealthStatus_Healthy {
        // Service is healthy
    }
}

API Reference

Daemon

Module(scope string) fx.Option

Creates a Daemon module and returns an Fx Option.

• scope: Module namespace for logger naming

Ready() bool

Returns true if the daemon has started and is ready to serve requests.

GetHealthStatus() HealthStatus

Returns the current health status of the daemon.

HealthStatus

const (
    HealthStatus_Healthy   HealthStatus = iota  // Service is healthy
    HealthStatus_Unhealthy                       // Service is unhealthy
)

Integration with Health Check APIs

The daemon module is designed to work with the healthcheck_apis module:

package main

import (
    "github.com/weedbox/common-modules/daemon"
    "github.com/weedbox/common-modules/healthcheck_apis"
    "github.com/weedbox/common-modules/http_server"
    "github.com/weedbox/common-modules/logger"
    "go.uber.org/fx"
)

func main() {
    fx.New(
        logger.Module(),
        http_server.Module("http_server"),
        healthcheck_apis.Module("healthcheck_apis"),

        // Other application modules...

        // Daemon must be last
        daemon.Module("daemon"),
    ).Run()
}

This exposes:

• GET /healthz - Returns health status
• GET /ready - Returns ready state (only true after all modules are initialized)

License

Apache License 2.0

Documentation

Index

• func Module(scope string) fx.Option
• type Daemon
  • func (d *Daemon) GetHealthStatus() HealthStatus
  • func (d *Daemon) Ready() bool
• type HealthStatus
• type Params

Functions

func Module

func Module(scope string) fx.Option

Types

type Daemon

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

func (*Daemon) GetHealthStatus

func (d *Daemon) GetHealthStatus() HealthStatus

func (*Daemon) Ready

func (d *Daemon) Ready() bool

type HealthStatus

type HealthStatus int32

const (
	HealthStatus_Healthy HealthStatus = iota
	HealthStatus_Unhealthy
)

type Params

type Params struct {
	fx.In

	Lifecycle fx.Lifecycle
	Logger    *zap.Logger
}