ipfs-cluster/cmd/ipfs-cluster-service/lock.go
Hector Sanjuan 063c5f1b78 Service: Select consensus on "init" (not on "daemon")
Fixes #865.

This makes the necessary changes so that consensu is selected on "init" with a
flag set, by default, to "crdt". This generates only a "crdt" or a "raft"
section, not both.

If the configuration file has a "raft" section, "raft" will be used to start
the daemon. If it has a "crdt" section, "crdt" will be used. If it has none or
both sections, an error will happen.

This also affects "state *" commands, which will now autoselect how to work
from the existing configuration.
2019-08-09 19:20:53 +02:00

72 lines
1.6 KiB
Go

package main
import (
"errors"
"fmt"
"io"
"path"
fslock "github.com/ipfs/go-fs-lock"
"github.com/ipfs/ipfs-cluster/cmdutils"
)
// lock logic heavily inspired by go-ipfs/repo/fsrepo/lock/lock.go
// The name of the file used for locking
const lockFileName = "cluster.lock"
var locker *lock
// lock helps to coordinate procees via a lock file
type lock struct {
lockCloser io.Closer
path string
}
func (l *lock) lock() {
if l.lockCloser != nil {
checkErr("", errors.New("cannot acquire lock twice"))
}
// we should have a config folder whenever we try to lock
cfgHelper := cmdutils.NewConfigHelper(configPath, identityPath, "")
cfgHelper.MakeConfigFolder()
// set the lock file within this function
logger.Debug("checking lock")
lk, err := fslock.Lock(l.path, lockFileName)
if err != nil {
logger.Debug(err)
l.lockCloser = nil
errStr := "%s. If no other "
errStr += "%s process is running, remove %s, or make sure "
errStr += "that the config folder is writable for the user "
errStr += "running %s."
errStr = fmt.Sprintf(
errStr,
err,
programName,
path.Join(l.path, lockFileName),
programName,
)
checkErr("obtaining execution lock", errors.New(errStr))
}
logger.Debugf("%s execution lock acquired", programName)
l.lockCloser = lk
}
func (l *lock) tryUnlock() error {
// Noop in the uninitialized case
if l.lockCloser == nil {
logger.Debug("locking not initialized, unlock is noop")
return nil
}
err := l.lockCloser.Close()
if err != nil {
return err
}
logger.Debug("successfully released execution lock")
l.lockCloser = nil
return nil
}