lnd.xprv/lncfg/cluster.go
Andras Banki-Horvath d161b34ee5
lnd: integrate leader elector to lnd main
This commit also changes the order of DB init to be run after the RPC
server is up. This will allow us to later add an RPC endpoint to be used
to query leadership status.
2021-05-04 17:33:08 +02:00

75 lines
2.1 KiB
Go

package lncfg
import (
"context"
"fmt"
"os"
"github.com/lightningnetwork/lnd/cluster"
)
const (
// DefaultEtcdElectionPrefix is used as election prefix if none is provided
// through the config.
DefaultEtcdElectionPrefix = "/leader/"
)
// Cluster holds configuration for clustered LND.
type Cluster struct {
EnableLeaderElection bool `long:"enable-leader-election" description:"Enables leader election if set."`
LeaderElector string `long:"leader-elector" choice:"etcd" description:"Leader elector to use. Valid values: \"etcd\"."`
EtcdElectionPrefix string `long:"etcd-election-prefix" description:"Election key prefix when using etcd leader elector. Defaults to \"/leader/\"."`
ID string `long:"id" description:"Identifier for this node inside the cluster (used in leader election). Defaults to the hostname."`
}
// DefaultCluster creates and returns a new default DB config.
func DefaultCluster() *Cluster {
hostname, _ := os.Hostname()
return &Cluster{
LeaderElector: cluster.EtcdLeaderElector,
EtcdElectionPrefix: DefaultEtcdElectionPrefix,
ID: hostname,
}
}
// MakeLeaderElector is a helper method to construct the concrete leader elector
// based on the current configuration.
func (c *Cluster) MakeLeaderElector(electionCtx context.Context, db *DB) (
cluster.LeaderElector, error) {
if c.LeaderElector == cluster.EtcdLeaderElector {
return cluster.MakeLeaderElector(
electionCtx, c.LeaderElector, c.ID,
c.EtcdElectionPrefix, db.Etcd,
)
}
return nil, fmt.Errorf("unsupported leader elector")
}
// Validate validates the Cluster config.
func (c *Cluster) Validate() error {
if !c.EnableLeaderElection {
return nil
}
switch c.LeaderElector {
case cluster.EtcdLeaderElector:
if c.EtcdElectionPrefix == "" {
return fmt.Errorf("etcd-election-prefix must be set")
}
return nil
default:
return fmt.Errorf("unknown leader elector, valid values are: "+
"\"%v\"", cluster.EtcdLeaderElector)
}
}
// Compile-time constraint to ensure Workers implements the Validator interface.
var _ Validator = (*Cluster)(nil)