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- package guerrilla
- import (
- "encoding/json"
- "errors"
- "fmt"
- "github.com/flashmob/go-guerrilla/backends"
- "github.com/flashmob/go-guerrilla/log"
- "io/ioutil"
- "time"
- )
- // Daemon provides a convenient API when using go-guerrilla as a package in your Go project.
- // Is's facade for Guerrilla, AppConfig, backends.Backend and log.Logger
- type Daemon struct {
- Config *AppConfig
- Logger log.Logger
- Backend backends.Backend
- // Guerrilla will be managed through the API
- g Guerrilla
- configLoadTime time.Time
- subs []deferredSub
- }
- type deferredSub struct {
- topic Event
- fn interface{}
- }
- // AddProcessor adds a processor constructor to the backend.
- // name is the identifier to be used in the config. See backends docs for more info.
- func (d *Daemon) AddProcessor(name string, pc backends.ProcessorConstructor) {
- backends.Svc.AddProcessor(name, pc)
- }
- // Starts the daemon, initializing d.Config, d.Logger and d.Backend with defaults
- // can only be called once through the lifetime of the program
- func (d *Daemon) Start() (err error) {
- if d.g == nil {
- if d.Config == nil {
- d.Config = &AppConfig{}
- }
- if err = d.configureDefaults(); err != nil {
- return err
- }
- if d.Logger == nil {
- d.Logger, err = log.GetLogger(d.Config.LogFile, d.Config.LogLevel)
- if err != nil {
- return err
- }
- }
- if d.Backend == nil {
- d.Backend, err = backends.New(d.Config.BackendConfig, d.Logger)
- if err != nil {
- return err
- }
- }
- d.g, err = New(d.Config, d.Backend, d.Logger)
- if err != nil {
- return err
- }
- for i := range d.subs {
- _ = d.Subscribe(d.subs[i].topic, d.subs[i].fn)
- }
- d.subs = make([]deferredSub, 0)
- }
- err = d.g.Start()
- if err == nil {
- if err := d.resetLogger(); err == nil {
- d.Log().Infof("main log configured to %s", d.Config.LogFile)
- }
- }
- return err
- }
- // Shuts down the daemon, including servers and backend.
- // Do not call Start on it again, use a new server.
- func (d *Daemon) Shutdown() {
- if d.g != nil {
- d.g.Shutdown()
- }
- }
- // LoadConfig reads in the config from a JSON file.
- // Note: if d.Config is nil, the sets d.Config with the unmarshalled AppConfig which will be returned
- func (d *Daemon) LoadConfig(path string) (AppConfig, error) {
- var ac AppConfig
- data, err := ioutil.ReadFile(path)
- if err != nil {
- return ac, fmt.Errorf("could not read config file: %s", err.Error())
- }
- err = ac.Load(data)
- if err != nil {
- return ac, err
- }
- if d.Config == nil {
- d.Config = &ac
- }
- return ac, nil
- }
- // SetConfig is same as LoadConfig, except you can pass AppConfig directly
- // does not emit any change events, instead use ReloadConfig after daemon has started
- func (d *Daemon) SetConfig(c AppConfig) error {
- // need to call c.Load, thus need to convert the config
- // d.load takes json bytes, marshal it
- data, err := json.Marshal(&c)
- if err != nil {
- return err
- }
- err = c.Load(data)
- if err != nil {
- return err
- }
- d.Config = &c
- return nil
- }
- // Reload a config using the passed in AppConfig and emit config change events
- func (d *Daemon) ReloadConfig(c AppConfig) error {
- oldConfig := *d.Config
- err := d.SetConfig(c)
- if err != nil {
- d.Log().WithError(err).Error("Error while reloading config")
- return err
- }
- d.Log().Infof("Configuration was reloaded at %s", d.configLoadTime)
- d.Config.EmitChangeEvents(&oldConfig, d.g)
- return nil
- }
- // Reload a config from a file and emit config change events
- func (d *Daemon) ReloadConfigFile(path string) error {
- ac, err := d.LoadConfig(path)
- if err != nil {
- d.Log().WithError(err).Error("Error while reloading config from file")
- return err
- } else if d.Config != nil {
- oldConfig := *d.Config
- d.Config = &ac
- d.Log().Infof("Configuration was reloaded at %s", d.configLoadTime)
- d.Config.EmitChangeEvents(&oldConfig, d.g)
- }
- return nil
- }
- // ReopenLogs send events to re-opens all log files.
- // Typically, one would call this after rotating logs
- func (d *Daemon) ReopenLogs() error {
- if d.Config == nil {
- return errors.New("d.Config nil")
- }
- d.Config.EmitLogReopenEvents(d.g)
- return nil
- }
- // Subscribe for subscribing to config change events
- func (d *Daemon) Subscribe(topic Event, fn interface{}) error {
- if d.g == nil {
- // defer the subscription until the daemon is started
- d.subs = append(d.subs, deferredSub{topic, fn})
- return nil
- }
- return d.g.Subscribe(topic, fn)
- }
- // for publishing config change events
- func (d *Daemon) Publish(topic Event, args ...interface{}) {
- if d.g == nil {
- return
- }
- d.g.Publish(topic, args...)
- }
- // for unsubscribing from config change events
- func (d *Daemon) Unsubscribe(topic Event, handler interface{}) error {
- if d.g == nil {
- for i := range d.subs {
- if d.subs[i].topic == topic && d.subs[i].fn == handler {
- d.subs = append(d.subs[:i], d.subs[i+1:]...)
- }
- }
- return nil
- }
- return d.g.Unsubscribe(topic, handler)
- }
- // log returns a logger that implements our log.Logger interface.
- // level is set to "info" by default
- func (d *Daemon) Log() log.Logger {
- if d.Logger != nil {
- return d.Logger
- }
- out := log.OutputStderr.String()
- level := log.InfoLevel.String()
- if d.Config != nil {
- if len(d.Config.LogFile) > 0 {
- out = d.Config.LogFile
- }
- if len(d.Config.LogLevel) > 0 {
- level = d.Config.LogLevel
- }
- }
- l, _ := log.GetLogger(out, level)
- return l
- }
- // set the default values for the servers and backend config options
- func (d *Daemon) configureDefaults() error {
- err := d.Config.setDefaults()
- if err != nil {
- return err
- }
- if d.Backend == nil {
- err = d.Config.setBackendDefaults()
- if err != nil {
- return err
- }
- }
- return err
- }
- // resetLogger sets the logger to the one specified in the config.
- // This is because at the start, the daemon may be logging to stderr,
- // then attaches to the logs once the config is loaded.
- // This will propagate down to the servers / backend too.
- func (d *Daemon) resetLogger() error {
- l, err := log.GetLogger(d.Config.LogFile, d.Config.LogLevel)
- if err != nil {
- return err
- }
- d.Logger = l
- d.g.SetLogger(d.Logger)
- return nil
- }
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