ipld-eth-beacon-indexer/pkg/gracefulshutdown/gracefulshutdown.go
2022-06-22 12:06:52 -04:00

91 lines
2.4 KiB
Go

// VulcanizeDB
// Copyright © 2022 Vulcanize
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package gracefulshutdown
import (
"context"
"fmt"
"os"
"os/signal"
"sync"
"syscall"
"time"
log "github.com/sirupsen/logrus"
"github.com/vulcanize/ipld-eth-beacon-indexer/pkg/loghelper"
)
// operation is a clean up function on shutting down
type Operation func(ctx context.Context) error
var (
TimeoutErr = func(timeout string) error {
return fmt.Errorf("The Timeout %s, has been elapsed, the application will forcefully exit", timeout)
}
)
// gracefulShutdown waits for termination syscalls and doing clean up operations after received it
func Shutdown(ctx context.Context, notifierCh chan os.Signal, timeout time.Duration, ops map[string]Operation) (<-chan struct{}, <-chan error) {
waitCh := make(chan struct{})
errCh := make(chan error)
go func() {
// add any other syscalls that you want to be notified with
signal.Notify(notifierCh, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
// Wait for one or the other...
select {
case <-notifierCh:
case <-ctx.Done():
}
log.Info("Shutting Down your application")
// set timeout for the ops to be done to prevent system hang
timeoutFunc := time.AfterFunc(timeout, func() {
log.Warnf(TimeoutErr(timeout.String()).Error())
errCh <- TimeoutErr(timeout.String())
})
defer timeoutFunc.Stop()
var wg sync.WaitGroup
// Do the operations asynchronously to save time
for key, op := range ops {
wg.Add(1)
innerOp := op
innerKey := key
go func() {
defer wg.Done()
log.Infof("cleaning up: %s", innerKey)
if err := innerOp(ctx); err != nil {
loghelper.LogError(err).Errorf("%s: clean up failed: %s", innerKey, err.Error())
return
}
log.Infof("%s was shutdown gracefully", innerKey)
}()
}
wg.Wait()
close(waitCh)
}()
return waitCh, errCh
}