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guerrilla.go
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package guerrilla
import (
"errors"
"fmt"
"os"
"sync"
"sync/atomic"
"github.com/flashmob/go-guerrilla/backends"
"github.com/flashmob/go-guerrilla/log"
)
const (
// all configured servers were just been created
daemonStateNew = iota
// ... been started and running
daemonStateStarted
// ... been stopped
daemonStateStopped
)
type Errors []error
// implement the Error interface
func (e Errors) Error() string {
if len(e) == 1 {
return e[0].Error()
}
// multiple errors
msg := ""
for _, err := range e {
msg += "\n" + err.Error()
}
return msg
}
type Guerrilla interface {
Start() error
Shutdown()
Subscribe(topic Event, fn interface{}) error
Publish(topic Event, args ...interface{})
Unsubscribe(topic Event, handler interface{}) error
SetLogger(log.Logger)
}
type guerrilla struct {
Config AppConfig
servers map[string]*server
// guard controls access to g.servers
guard sync.Mutex
state int8
EventHandler
logStore
backendStore
}
type logStore struct {
atomic.Value
}
type backendStore struct {
atomic.Value
}
type daemonEvent func(c *AppConfig)
type serverEvent func(sc *ServerConfig)
// Get loads the log.logger in an atomic operation. Returns a stderr logger if not able to load
func (ls *logStore) mainlog() log.Logger {
if v, ok := ls.Load().(log.Logger); ok {
return v
}
l, _ := log.GetLogger(log.OutputStderr.String(), log.InfoLevel.String())
return l
}
// setMainlog stores the log value in an atomic operation
func (ls *logStore) setMainlog(log log.Logger) {
ls.Store(log)
}
// Returns a new instance of Guerrilla with the given config, not yet running. Backend started.
func New(ac *AppConfig, b backends.Backend, l log.Logger) (Guerrilla, error) {
g := &guerrilla{
Config: *ac, // take a local copy
servers: make(map[string]*server, len(ac.Servers)),
}
g.backendStore.Store(b)
g.setMainlog(l)
if ac.LogLevel != "" {
if h, ok := l.(*log.HookedLogger); ok {
if h, err := log.GetLogger(h.GetLogDest(), ac.LogLevel); err == nil {
g.setMainlog(h)
}
}
}
// Write the process id (pid) to a file
// we should still be able to continue even if we can't write the pid, error will be logged by writePid()
_ = g.writePid()
g.state = daemonStateNew
err := g.makeServers()
if err != nil {
return g, err
}
// start backend for processing email
err = g.backend().Start()
if err != nil {
return g, err
}
// subscribe for any events that may come in while running
g.subscribeEvents()
return g, err
}
// Instantiate servers
func (g *guerrilla) makeServers() error {
g.mainlog().Debug("making servers")
var errs Errors
for _, sc := range g.Config.Servers {
if _, ok := g.servers[sc.ListenInterface]; ok {
// server already instantiated
continue
}
if err := sc.Validate(); err != nil {
g.mainlog().WithError(errs).Errorf("Failed to create server [%s]", sc.ListenInterface)
errs = append(errs, err)
continue
} else {
sc := sc // pin!
server, err := newServer(&sc, g.backend(), g.mainlog())
if err != nil {
g.mainlog().WithError(err).Errorf("Failed to create server [%s]", sc.ListenInterface)
errs = append(errs, err)
}
if server != nil {
g.servers[sc.ListenInterface] = server
server.setAllowedHosts(g.Config.AllowedHosts)
}
}
}
if len(g.servers) == 0 {
errs = append(errs, errors.New("there are no servers that can start, please check your config"))
}
if len(errs) == 0 {
return nil
}
return errs
}
// findServer finds a server by iface (interface), retuning the server or err
func (g *guerrilla) findServer(iface string) (*server, error) {
g.guard.Lock()
defer g.guard.Unlock()
if server, ok := g.servers[iface]; ok {
return server, nil
}
return nil, errors.New("server not found in g.servers")
}
// removeServer removes a server from the list of servers
func (g *guerrilla) removeServer(iface string) {
g.guard.Lock()
defer g.guard.Unlock()
delete(g.servers, iface)
}
// setConfig sets the app config
func (g *guerrilla) setConfig(c *AppConfig) {
g.guard.Lock()
defer g.guard.Unlock()
g.Config = *c
}
// setServerConfig config updates the server's config, which will update for the next connected client
func (g *guerrilla) setServerConfig(sc *ServerConfig) {
g.guard.Lock()
defer g.guard.Unlock()
if _, ok := g.servers[sc.ListenInterface]; ok {
g.servers[sc.ListenInterface].setConfig(sc)
}
}
// mapServers calls a callback on each server in g.servers map
// It locks the g.servers map before mapping
func (g *guerrilla) mapServers(callback func(*server)) map[string]*server {
defer g.guard.Unlock()
g.guard.Lock()
for _, server := range g.servers {
callback(server)
}
return g.servers
}
// subscribeEvents subscribes event handlers for configuration change events
func (g *guerrilla) subscribeEvents() {
events := map[Event]interface{}{}
// main config changed
events[EventConfigNewConfig] = daemonEvent(func(c *AppConfig) {
g.setConfig(c)
})
// allowed_hosts changed, set for all servers
events[EventConfigAllowedHosts] = daemonEvent(func(c *AppConfig) {
g.mapServers(func(server *server) {
server.setAllowedHosts(c.AllowedHosts)
})
g.mainlog().Infof("allowed_hosts config changed, a new list was set")
})
// the main log file changed
events[EventConfigLogFile] = daemonEvent(func(c *AppConfig) {
var err error
var l log.Logger
if l, err = log.GetLogger(c.LogFile, c.LogLevel); err == nil {
g.setMainlog(l)
g.mapServers(func(server *server) {
// it will change server's logger when the next client gets accepted
server.mainlogStore.Store(l)
})
g.mainlog().Infof("main log for new clients changed to [%s]", c.LogFile)
} else {
g.mainlog().WithError(err).Errorf("main logging change failed [%s]", c.LogFile)
}
})
// re-open the main log file (file not changed)
events[EventConfigLogReopen] = daemonEvent(func(c *AppConfig) {
err := g.mainlog().Reopen()
if err != nil {
g.mainlog().WithError(err).Errorf("main log file [%s] failed to re-open", c.LogFile)
return
}
g.mainlog().Infof("re-opened main log file [%s]", c.LogFile)
})
// when log level changes, apply to mainlog and server logs
events[EventConfigLogLevel] = daemonEvent(func(c *AppConfig) {
l, err := log.GetLogger(g.mainlog().GetLogDest(), c.LogLevel)
if err == nil {
g.logStore.Store(l)
g.mapServers(func(server *server) {
server.logStore.Store(l)
})
g.mainlog().Infof("log level changed to [%s]", c.LogLevel)
}
})
// write out our pid whenever the file name changes in the config
events[EventConfigPidFile] = daemonEvent(func(ac *AppConfig) {
_ = g.writePid()
})
// server config was updated
events[EventConfigServerConfig] = serverEvent(func(sc *ServerConfig) {
g.setServerConfig(sc)
g.mainlog().Infof("server %s config change event, a new config has been saved", sc.ListenInterface)
})
// add a new server to the config & start
events[EventConfigServerNew] = serverEvent(func(sc *ServerConfig) {
g.mainlog().Debugf("event fired [%s] %s", EventConfigServerNew, sc.ListenInterface)
if _, err := g.findServer(sc.ListenInterface); err != nil {
// not found, lets add it
//
if err := g.makeServers(); err != nil {
g.mainlog().WithError(err).Errorf("cannot add server [%s]", sc.ListenInterface)
return
}
g.mainlog().Infof("New server added [%s]", sc.ListenInterface)
if g.state == daemonStateStarted {
err := g.Start()
if err != nil {
g.mainlog().WithError(err).Info("Event server_change:new_server returned errors when starting")
}
}
} else {
g.mainlog().Debugf("new event, but server already fund")
}
})
// start a server that already exists in the config and has been enabled
events[EventConfigServerStart] = serverEvent(func(sc *ServerConfig) {
if server, err := g.findServer(sc.ListenInterface); err == nil {
if server.state == ServerStateStopped || server.state == ServerStateNew {
g.mainlog().Infof("Starting server [%s]", server.listenInterface)
err := g.Start()
if err != nil {
g.mainlog().WithError(err).Info("Event server_change:start_server returned errors when starting")
}
}
}
})
// stop running a server
events[EventConfigServerStop] = serverEvent(func(sc *ServerConfig) {
if server, err := g.findServer(sc.ListenInterface); err == nil {
if server.state == ServerStateRunning {
server.Shutdown()
g.mainlog().Infof("Server [%s] stopped.", sc.ListenInterface)
}
}
})
// server was removed from config
events[EventConfigServerRemove] = serverEvent(func(sc *ServerConfig) {
if server, err := g.findServer(sc.ListenInterface); err == nil {
server.Shutdown()
g.removeServer(sc.ListenInterface)
g.mainlog().Infof("Server [%s] removed from config, stopped it.", sc.ListenInterface)
}
})
// TLS changes
events[EventConfigServerTLSConfig] = serverEvent(func(sc *ServerConfig) {
if server, err := g.findServer(sc.ListenInterface); err == nil {
if err := server.configureTLS(); err == nil {
g.mainlog().Infof("Server [%s] new TLS configuration loaded", sc.ListenInterface)
} else {
g.mainlog().WithError(err).Errorf("Server [%s] failed to load the new TLS configuration", sc.ListenInterface)
}
}
})
// when server's timeout change.
events[EventConfigServerTimeout] = serverEvent(func(sc *ServerConfig) {
g.mapServers(func(server *server) {
server.setTimeout(sc.Timeout)
})
})
// when server's max clients change.
events[EventConfigServerMaxClients] = serverEvent(func(sc *ServerConfig) {
g.mapServers(func(server *server) {
// TODO resize the pool somehow
})
})
// when a server's log file changes
events[EventConfigServerLogFile] = serverEvent(func(sc *ServerConfig) {
if server, err := g.findServer(sc.ListenInterface); err == nil {
var err error
var l log.Logger
level := g.mainlog().GetLevel()
if l, err = log.GetLogger(sc.LogFile, level); err == nil {
g.setMainlog(l)
backends.Svc.SetMainlog(l)
// it will change to the new logger on the next accepted client
server.logStore.Store(l)
g.mainlog().Infof("Server [%s] changed, new clients will log to: [%s]",
sc.ListenInterface,
sc.LogFile,
)
} else {
g.mainlog().WithError(err).Errorf(
"Server [%s] log change failed to: [%s]",
sc.ListenInterface,
sc.LogFile,
)
}
}
})
// when the daemon caught a sighup, event for individual server
events[EventConfigServerLogReopen] = serverEvent(func(sc *ServerConfig) {
if server, err := g.findServer(sc.ListenInterface); err == nil {
if err = server.log().Reopen(); err != nil {
g.mainlog().WithError(err).Errorf("server [%s] log file [%s] failed to re-open", sc.ListenInterface, sc.LogFile)
return
}
g.mainlog().Infof("Server [%s] re-opened log file [%s]", sc.ListenInterface, sc.LogFile)
}
})
// when the backend changes
events[EventConfigBackendConfig] = daemonEvent(func(appConfig *AppConfig) {
logger, _ := log.GetLogger(appConfig.LogFile, appConfig.LogLevel)
// shutdown the backend first.
var err error
if err = g.backend().Shutdown(); err != nil {
logger.WithError(err).Warn("Backend failed to shutdown")
return
}
// init a new backend, Revert to old backend config if it fails
if newBackend, newErr := backends.New(appConfig.BackendConfig, logger); newErr != nil {
logger.WithError(newErr).Error("Error while loading the backend")
err = g.backend().Reinitialize()
if err != nil {
logger.WithError(err).Fatal("failed to revert to old backend config")
return
}
err = g.backend().Start()
if err != nil {
logger.WithError(err).Fatal("failed to start backend with old config")
return
}
logger.Info("reverted to old backend config")
} else {
// swap to the bew backend (assuming old backend was shutdown so it can be safely swapped)
if err := newBackend.Start(); err != nil {
logger.WithError(err).Error("backend could not start")
}
logger.Info("new backend started")
g.storeBackend(newBackend)
}
})
var err error
for topic, fn := range events {
switch f := fn.(type) {
case daemonEvent:
err = g.Subscribe(topic, f)
case serverEvent:
err = g.Subscribe(topic, f)
}
if err != nil {
g.mainlog().WithError(err).Errorf("failed to subscribe on topic [%s]", topic)
break
}
}
}
func (g *guerrilla) storeBackend(b backends.Backend) {
g.backendStore.Store(b)
g.mapServers(func(server *server) {
server.setBackend(b)
})
}
func (g *guerrilla) backend() backends.Backend {
if b, ok := g.backendStore.Load().(backends.Backend); ok {
return b
}
return nil
}
// Entry point for the application. Starts all servers.
func (g *guerrilla) Start() error {
var startErrors Errors
g.guard.Lock()
defer func() {
g.state = daemonStateStarted
g.guard.Unlock()
}()
if len(g.servers) == 0 {
return append(startErrors, errors.New("no servers to start, please check the config"))
}
if g.state == daemonStateStopped {
// when a backend is shutdown, we need to re-initialize before it can be started again
if err := g.backend().Reinitialize(); err != nil {
startErrors = append(startErrors, err)
}
if err := g.backend().Start(); err != nil {
startErrors = append(startErrors, err)
}
}
// channel for reading errors
errs := make(chan error, len(g.servers))
var startWG sync.WaitGroup
// start servers, send any errors back to errs channel
for ListenInterface := range g.servers {
if !g.servers[ListenInterface].isEnabled() {
// not enabled
continue
}
if g.servers[ListenInterface].state != ServerStateNew &&
g.servers[ListenInterface].state != ServerStateStopped {
continue
}
startWG.Add(1)
go func(s *server) {
g.mainlog().Infof("Starting: %s", s.listenInterface)
if err := s.Start(&startWG); err != nil {
errs <- err
}
}(g.servers[ListenInterface])
}
// wait for all servers to start (or fail)
startWG.Wait()
// close, then read any errors
close(errs)
for err := range errs {
if err != nil {
startErrors = append(startErrors, err)
}
}
if len(startErrors) > 0 {
return startErrors
}
return nil
}
func (g *guerrilla) Shutdown() {
// shut down the servers first
g.mapServers(func(s *server) {
if s.state == ServerStateRunning {
s.Shutdown()
g.mainlog().Infof("shutdown completed for [%s]", s.listenInterface)
}
})
g.guard.Lock()
defer func() {
g.state = daemonStateStopped
defer g.guard.Unlock()
}()
if err := g.backend().Shutdown(); err != nil {
g.mainlog().WithError(err).Warn("Backend failed to shutdown")
} else {
g.mainlog().Infof("Backend shutdown completed")
}
}
// SetLogger sets the logger for the app and propagates it to sub-packages (eg.
func (g *guerrilla) SetLogger(l log.Logger) {
g.setMainlog(l)
backends.Svc.SetMainlog(l)
}
// writePid writes the pid (process id) to the file specified in the config.
// Won't write anything if no file specified
func (g *guerrilla) writePid() (err error) {
var f *os.File
defer func() {
if f != nil {
if closeErr := f.Close(); closeErr != nil {
err = closeErr
}
}
if err != nil {
g.mainlog().WithError(err).Errorf("error while writing pidFile (%s)", g.Config.PidFile)
}
}()
if len(g.Config.PidFile) > 0 {
if f, err = os.Create(g.Config.PidFile); err != nil {
return err
}
pid := os.Getpid()
if _, err := f.WriteString(fmt.Sprintf("%d", pid)); err != nil {
return err
}
if err = f.Sync(); err != nil {
return err
}
g.mainlog().Infof("pid_file (%s) written with pid:%v", g.Config.PidFile, pid)
}
return nil
}
// CheckFileLimit checks the number of files we can open (works on OS'es that support the ulimit command)
func CheckFileLimit(c *AppConfig) (bool, int, uint64) {
fileLimit, err := getFileLimit()
maxClients := 0
if err != nil {
// since we can't get the limit, return true to indicate the check passed
return true, maxClients, fileLimit
}
if c.Servers == nil {
// no servers have been configured, assuming default
maxClients = defaultMaxClients
} else {
for _, s := range c.Servers {
maxClients += s.MaxClients
}
}
if uint64(maxClients) > fileLimit {
return false, maxClients, fileLimit
}
return true, maxClients, fileLimit
}