lnd.xprv/lncfg/cluster.go

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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)