gatus/main.go
2022-12-06 01:41:18 -05:00

112 lines
3.1 KiB
Go

package main
import (
"log"
"os"
"os/signal"
"syscall"
"time"
"github.com/TwiN/gatus/v5/config"
"github.com/TwiN/gatus/v5/controller"
"github.com/TwiN/gatus/v5/storage/store"
"github.com/TwiN/gatus/v5/watchdog"
)
func main() {
cfg, err := loadConfiguration()
if err != nil {
panic(err)
}
initializeStorage(cfg)
start(cfg)
// Wait for termination signal
signalChannel := make(chan os.Signal, 1)
done := make(chan bool, 1)
signal.Notify(signalChannel, os.Interrupt, syscall.SIGTERM)
go func() {
<-signalChannel
log.Println("Received termination signal, attempting to gracefully shut down")
stop()
save()
done <- true
}()
<-done
log.Println("Shutting down")
}
func start(cfg *config.Config) {
go controller.Handle(cfg)
watchdog.Monitor(cfg)
go listenToConfigurationFileChanges(cfg)
}
func stop() {
watchdog.Shutdown()
controller.Shutdown()
}
func save() {
if err := store.Get().Save(); err != nil {
log.Println("Failed to save storage provider:", err.Error())
}
}
func loadConfiguration() (cfg *config.Config, err error) {
customConfigFile := os.Getenv("GATUS_CONFIG_FILE")
if len(customConfigFile) > 0 {
cfg, err = config.Load(customConfigFile)
} else {
cfg, err = config.LoadDefaultConfiguration()
}
return
}
// initializeStorage initializes the storage provider
//
// Q: "TwiN, why are you putting this here? Wouldn't it make more sense to have this in the config?!"
// A: Yes. Yes it would make more sense to have it in the config package. But I don't want to import
// the massive SQL dependencies just because I want to import the config, so here we are.
func initializeStorage(cfg *config.Config) {
err := store.Initialize(cfg.Storage)
if err != nil {
panic(err)
}
// Remove all EndpointStatus that represent endpoints which no longer exist in the configuration
var keys []string
for _, endpoint := range cfg.Endpoints {
keys = append(keys, endpoint.Key())
}
numberOfEndpointStatusesDeleted := store.Get().DeleteAllEndpointStatusesNotInKeys(keys)
if numberOfEndpointStatusesDeleted > 0 {
log.Printf("[config][validateStorageConfig] Deleted %d endpoint statuses because their matching endpoints no longer existed", numberOfEndpointStatusesDeleted)
}
}
func listenToConfigurationFileChanges(cfg *config.Config) {
for {
time.Sleep(30 * time.Second)
if cfg.HasLoadedConfigurationFileBeenModified() {
log.Println("[main][listenToConfigurationFileChanges] Configuration file has been modified")
stop()
time.Sleep(time.Second) // Wait a bit to make sure everything is done.
save()
updatedConfig, err := loadConfiguration()
if err != nil {
if cfg.SkipInvalidConfigUpdate {
log.Println("[main][listenToConfigurationFileChanges] Failed to load new configuration:", err.Error())
log.Println("[main][listenToConfigurationFileChanges] The configuration file was updated, but it is not valid. The old configuration will continue being used.")
// Update the last file modification time to avoid trying to process the same invalid configuration again
cfg.UpdateLastFileModTime()
continue
} else {
panic(err)
}
}
initializeStorage(updatedConfig)
start(updatedConfig)
return
}
}
}