open-consul/agent/consul/state/autopilot.go
Daniel Nephin 7cb2255838 state: use ReadTxn and WriteTxn interface
Instead of *txn, so that we can replace the txn implementation with others, and so
that the function is easily documented as a read or write function.
2021-03-29 18:52:16 -04:00

133 lines
3.4 KiB
Go

package state
import (
"fmt"
"github.com/hashicorp/go-memdb"
"github.com/hashicorp/consul/agent/structs"
)
// autopilotConfigTableSchema returns a new table schema used for storing
// the autopilot configuration
func autopilotConfigTableSchema() *memdb.TableSchema {
return &memdb.TableSchema{
Name: "autopilot-config",
Indexes: map[string]*memdb.IndexSchema{
"id": {
Name: "id",
AllowMissing: true,
Unique: true,
Indexer: &memdb.ConditionalIndex{
Conditional: func(obj interface{}) (bool, error) { return true, nil },
},
},
},
}
}
// Autopilot is used to pull the autopilot config from the snapshot.
func (s *Snapshot) Autopilot() (*structs.AutopilotConfig, error) {
c, err := s.tx.First("autopilot-config", "id")
if err != nil {
return nil, err
}
config, ok := c.(*structs.AutopilotConfig)
if !ok {
return nil, nil
}
return config, nil
}
// Autopilot is used when restoring from a snapshot.
func (s *Restore) Autopilot(config *structs.AutopilotConfig) error {
if err := s.tx.Insert("autopilot-config", config); err != nil {
return fmt.Errorf("failed restoring autopilot config: %s", err)
}
return nil
}
// AutopilotConfig is used to get the current Autopilot configuration.
func (s *Store) AutopilotConfig() (uint64, *structs.AutopilotConfig, error) {
tx := s.db.Txn(false)
defer tx.Abort()
// Get the autopilot config
c, err := tx.First("autopilot-config", "id")
if err != nil {
return 0, nil, fmt.Errorf("failed autopilot config lookup: %s", err)
}
config, ok := c.(*structs.AutopilotConfig)
if !ok {
return 0, nil, nil
}
return config.ModifyIndex, config, nil
}
// AutopilotSetConfig is used to set the current Autopilot configuration.
func (s *Store) AutopilotSetConfig(idx uint64, config *structs.AutopilotConfig) error {
tx := s.db.WriteTxn(idx)
defer tx.Abort()
if err := autopilotSetConfigTxn(tx, idx, config); err != nil {
return err
}
return tx.Commit()
}
// AutopilotCASConfig is used to try updating the Autopilot configuration with a
// given Raft index. If the CAS index specified is not equal to the last observed index
// for the config, then the call is a noop,
func (s *Store) AutopilotCASConfig(idx, cidx uint64, config *structs.AutopilotConfig) (bool, error) {
tx := s.db.WriteTxn(idx)
defer tx.Abort()
// Check for an existing config
existing, err := tx.First("autopilot-config", "id")
if err != nil {
return false, fmt.Errorf("failed autopilot config lookup: %s", err)
}
// If the existing index does not match the provided CAS
// index arg, then we shouldn't update anything and can safely
// return early here.
e, ok := existing.(*structs.AutopilotConfig)
if !ok || e.ModifyIndex != cidx {
return false, nil
}
if err := autopilotSetConfigTxn(tx, idx, config); err != nil {
return false, err
}
err = tx.Commit()
return err == nil, err
}
func autopilotSetConfigTxn(tx WriteTxn, idx uint64, config *structs.AutopilotConfig) error {
// Check for an existing config
existing, err := tx.First("autopilot-config", "id")
if err != nil {
return fmt.Errorf("failed autopilot config lookup: %s", err)
}
// Set the indexes.
if existing != nil {
config.CreateIndex = existing.(*structs.AutopilotConfig).CreateIndex
} else {
config.CreateIndex = idx
}
config.ModifyIndex = idx
if err := tx.Insert("autopilot-config", config); err != nil {
return fmt.Errorf("failed updating autopilot config: %s", err)
}
return nil
}