lnd.xprv/lncfg/db.go
Andras Banki-Horvath 9992e5c0b5
etcd: decouple embedded etcd instance startup
This refactor changes how we instantiate the etcd based Backend to allow
separate initialization and startup for the embedded instance.
2021-05-04 17:33:05 +02:00

135 lines
3.6 KiB
Go

package lncfg
import (
"context"
"fmt"
"time"
"github.com/lightningnetwork/lnd/channeldb/kvdb"
"github.com/lightningnetwork/lnd/channeldb/kvdb/etcd"
)
const (
dbName = "channel.db"
BoltBackend = "bolt"
EtcdBackend = "etcd"
DefaultBatchCommitInterval = 500 * time.Millisecond
)
// DB holds database configuration for LND.
type DB struct {
Backend string `long:"backend" description:"The selected database backend."`
BatchCommitInterval time.Duration `long:"batch-commit-interval" description:"The maximum duration the channel graph batch schedulers will wait before attempting to commit a batch of pending updates. This can be tradeoff database contenion for commit latency."`
Etcd *etcd.Config `group:"etcd" namespace:"etcd" description:"Etcd settings."`
Bolt *kvdb.BoltConfig `group:"bolt" namespace:"bolt" description:"Bolt settings."`
}
// NewDB creates and returns a new default DB config.
func DefaultDB() *DB {
return &DB{
Backend: BoltBackend,
BatchCommitInterval: DefaultBatchCommitInterval,
Bolt: &kvdb.BoltConfig{
AutoCompactMinAge: kvdb.DefaultBoltAutoCompactMinAge,
DBTimeout: kvdb.DefaultDBTimeout,
},
}
}
// Validate validates the DB config.
func (db *DB) Validate() error {
switch db.Backend {
case BoltBackend:
case EtcdBackend:
if !db.Etcd.Embedded && db.Etcd.Host == "" {
return fmt.Errorf("etcd host must be set")
}
default:
return fmt.Errorf("unknown backend, must be either \"%v\" or \"%v\"",
BoltBackend, EtcdBackend)
}
return nil
}
// Init should be called upon start to pre-initialize database access dependent
// on configuration.
func (db *DB) Init(ctx context.Context, dbPath string) error {
// Start embedded etcd server if requested.
if db.Backend == EtcdBackend && db.Etcd.Embedded {
cfg, _, err := kvdb.StartEtcdTestBackend(
dbPath, db.Etcd.EmbeddedClientPort,
db.Etcd.EmbeddedPeerPort,
)
if err != nil {
return err
}
// Override the original config with the config for
// the embedded instance.
db.Etcd = cfg
}
return nil
}
// DatabaseBackends is a two-tuple that holds the set of active database
// backends for the daemon. The two backends we expose are the local database
// backend, and the remote backend. The LocalDB attribute will always be
// populated. However, the remote DB will only be set if a replicated database
// is active.
type DatabaseBackends struct {
// LocalDB points to the local non-replicated backend.
LocalDB kvdb.Backend
// RemoteDB points to a possibly networked replicated backend. If no
// replicated backend is active, then this pointer will be nil.
RemoteDB kvdb.Backend
}
// GetBackends returns a set of kvdb.Backends as set in the DB config. The
// local database will ALWAYS be non-nil, while the remote database will only
// be populated if etcd is specified.
func (db *DB) GetBackends(ctx context.Context, dbPath string) (
*DatabaseBackends, error) {
var (
localDB, remoteDB kvdb.Backend
err error
)
if db.Backend == EtcdBackend {
remoteDB, err = kvdb.Open(
kvdb.EtcdBackendName, ctx, db.Etcd,
)
if err != nil {
return nil, err
}
}
localDB, err = kvdb.GetBoltBackend(&kvdb.BoltBackendConfig{
DBPath: dbPath,
DBFileName: dbName,
DBTimeout: db.Bolt.DBTimeout,
NoFreelistSync: !db.Bolt.SyncFreelist,
AutoCompact: db.Bolt.AutoCompact,
AutoCompactMinAge: db.Bolt.AutoCompactMinAge,
})
if err != nil {
return nil, err
}
return &DatabaseBackends{
LocalDB: localDB,
RemoteDB: remoteDB,
}, nil
}
// Compile-time constraint to ensure Workers implements the Validator interface.
var _ Validator = (*DB)(nil)