wings/server/state.go
Matthew Penner de51fd1c51
Error handling improvements (#71)
* Remove `emperror.dev/errors`, remove all `errors#Wrap` and `errors#WithStack` calls
* Improve logging in `server/backup.go`
2020-11-28 16:57:10 -07:00

139 lines
4.2 KiB
Go

package server
import (
"encoding/json"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/environment"
"io"
"io/ioutil"
"os"
"sync"
)
var stateMutex sync.Mutex
// Returns the state of the servers.
func CachedServerStates() (map[string]string, error) {
// Request a lock after we check if the file exists.
stateMutex.Lock()
defer stateMutex.Unlock()
// Open the states file.
f, err := os.OpenFile(config.Get().System.GetStatesPath(), os.O_RDONLY|os.O_CREATE, 0644)
if err != nil {
return nil, err
}
defer f.Close()
// Convert the json object to a map.
states := map[string]string{}
if err := json.NewDecoder(f).Decode(&states); err != nil && err != io.EOF {
return nil, err
}
return states, nil
}
// saveServerStates .
func saveServerStates() error {
// Get the states of all servers on the daemon.
states := map[string]string{}
for _, s := range GetServers().All() {
states[s.Id()] = s.Environment.State()
}
// Convert the map to a json object.
data, err := json.Marshal(states)
if err != nil {
return err
}
stateMutex.Lock()
defer stateMutex.Unlock()
// Write the data to the file
if err := ioutil.WriteFile(config.Get().System.GetStatesPath(), data, 0644); err != nil {
return err
}
return nil
}
// Sets the state of the server internally. This function handles crash detection as
// well as reporting to event listeners for the server.
func (s *Server) OnStateChange() {
prevState := s.Proc().State.Load()
st := s.Environment.State()
// Update the currently tracked state for the server.
s.Proc().State.Store(st)
// Emit the event to any listeners that are currently registered.
if prevState != s.Environment.State() {
s.Log().WithField("status", st).Debug("saw server status change event")
s.Events().Publish(StatusEvent, st)
}
// Persist this change to the disk immediately so that should the Daemon be stopped or
// crash we can immediately restore the server state.
//
// This really only makes a difference if all of the Docker containers are also stopped,
// but this was a highly requested feature and isn't hard to work with, so lets do it.
//
// We also get the benefit of server status changes always propagating corrected configurations
// to the disk should we forget to do it elsewhere.
go func() {
if err := saveServerStates(); err != nil {
s.Log().WithField("error", err).Warn("failed to write server states to disk")
}
}()
// Reset the resource usage to 0 when the process fully stops so that all of the UI
// views in the Panel correctly display 0.
if st == environment.ProcessOfflineState {
s.resources.mu.Lock()
s.resources.Empty()
s.resources.mu.Unlock()
s.emitProcUsage()
}
// If server was in an online state, and is now in an offline state we should handle
// that as a crash event. In that scenario, check the last crash time, and the crash
// counter.
//
// In the event that we have passed the thresholds, don't do anything, otherwise
// automatically attempt to start the process back up for the user. This is done in a
// separate thread as to not block any actions currently taking place in the flow
// that called this function.
if (prevState == environment.ProcessStartingState || prevState == environment.ProcessRunningState) && s.Environment.State() == environment.ProcessOfflineState {
s.Log().Info("detected server as entering a crashed state; running crash handler")
go func(server *Server) {
if err := server.handleServerCrash(); err != nil {
if IsTooFrequentCrashError(err) {
server.Log().Info("did not restart server after crash; occurred too soon after the last")
} else {
server.Log().WithField("error", err).Error("failed to handle server crash")
}
}
}(s)
}
}
// Returns the current state of the server in a race-safe manner.
// Deprecated
// use Environment.State()
func (s *Server) GetState() string {
return s.Environment.State()
}
// Determines if the server state is running or not. This is different than the
// environment state, it is simply the tracked state from this daemon instance, and
// not the response from Docker.
func (s *Server) IsRunning() bool {
st := s.Environment.State()
return st == environment.ProcessRunningState || st == environment.ProcessStartingState
}