open-consul/agent/consul/state/system_metadata.go

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package state
import (
"fmt"
"github.com/hashicorp/consul/agent/structs"
memdb "github.com/hashicorp/go-memdb"
)
const systemMetadataTableName = "system-metadata"
func systemMetadataTableSchema() *memdb.TableSchema {
return &memdb.TableSchema{
Name: systemMetadataTableName,
Indexes: map[string]*memdb.IndexSchema{
"id": {
Name: "id",
AllowMissing: false,
Unique: true,
Indexer: &memdb.StringFieldIndex{
Field: "Key",
Lowercase: true,
},
},
},
}
}
func init() {
registerSchema(systemMetadataTableSchema)
}
// SystemMetadataEntries used to pull all the system metadata entries for the snapshot.
func (s *Snapshot) SystemMetadataEntries() ([]*structs.SystemMetadataEntry, error) {
entries, err := s.tx.Get(systemMetadataTableName, "id")
if err != nil {
return nil, err
}
var ret []*structs.SystemMetadataEntry
for wrapped := entries.Next(); wrapped != nil; wrapped = entries.Next() {
ret = append(ret, wrapped.(*structs.SystemMetadataEntry))
}
return ret, nil
}
// SystemMetadataEntry is used when restoring from a snapshot.
func (s *Restore) SystemMetadataEntry(entry *structs.SystemMetadataEntry) error {
// Insert
if err := s.tx.Insert(systemMetadataTableName, entry); err != nil {
return fmt.Errorf("failed restoring system metadata object: %s", err)
}
if err := indexUpdateMaxTxn(s.tx, entry.ModifyIndex, systemMetadataTableName); err != nil {
return fmt.Errorf("failed updating index: %s", err)
}
return nil
}
// SystemMetadataSet is called to do an upsert of a set of system metadata entries.
func (s *Store) SystemMetadataSet(idx uint64, entry *structs.SystemMetadataEntry) error {
tx := s.db.WriteTxn(idx)
defer tx.Abort()
if err := systemMetadataSetTxn(tx, idx, entry); err != nil {
return err
}
return tx.Commit()
}
// systemMetadataSetTxn upserts a system metadata inside of a transaction.
func systemMetadataSetTxn(tx *txn, idx uint64, entry *structs.SystemMetadataEntry) error {
// The only validation we care about is non-empty keys.
if entry.Key == "" {
return fmt.Errorf("missing key on system metadata")
}
// Check for existing.
var existing *structs.SystemMetadataEntry
existingRaw, err := tx.First(systemMetadataTableName, "id", entry.Key)
if err != nil {
return fmt.Errorf("failed system metadata lookup: %s", err)
}
if existingRaw != nil {
existing = existingRaw.(*structs.SystemMetadataEntry)
}
// Set the indexes
if existing != nil {
entry.CreateIndex = existing.CreateIndex
entry.ModifyIndex = idx
} else {
entry.CreateIndex = idx
entry.ModifyIndex = idx
}
// Insert the system metadata and update the index
if err := tx.Insert(systemMetadataTableName, entry); err != nil {
return fmt.Errorf("failed inserting system metadata: %s", err)
}
if err := tx.Insert("index", &IndexEntry{systemMetadataTableName, idx}); err != nil {
return fmt.Errorf("failed updating index: %v", err)
}
return nil
}
// SystemMetadataGet is called to get a system metadata.
func (s *Store) SystemMetadataGet(ws memdb.WatchSet, key string) (uint64, *structs.SystemMetadataEntry, error) {
tx := s.db.ReadTxn()
defer tx.Abort()
return systemMetadataGetTxn(tx, ws, key)
}
func systemMetadataGetTxn(tx ReadTxn, ws memdb.WatchSet, key string) (uint64, *structs.SystemMetadataEntry, error) {
// Get the index
idx := maxIndexTxn(tx, systemMetadataTableName)
// Get the existing contents.
watchCh, existing, err := tx.FirstWatch(systemMetadataTableName, "id", key)
if err != nil {
return 0, nil, fmt.Errorf("failed system metadata lookup: %s", err)
}
ws.Add(watchCh)
if existing == nil {
return idx, nil, nil
}
entry, ok := existing.(*structs.SystemMetadataEntry)
if !ok {
return 0, nil, fmt.Errorf("system metadata %q is an invalid type: %T", key, existing)
}
return idx, entry, nil
}
// SystemMetadataList is called to get all system metadata objects.
func (s *Store) SystemMetadataList(ws memdb.WatchSet) (uint64, []*structs.SystemMetadataEntry, error) {
tx := s.db.ReadTxn()
defer tx.Abort()
return systemMetadataListTxn(tx, ws)
}
func systemMetadataListTxn(tx ReadTxn, ws memdb.WatchSet) (uint64, []*structs.SystemMetadataEntry, error) {
// Get the index
idx := maxIndexTxn(tx, systemMetadataTableName)
iter, err := tx.Get(systemMetadataTableName, "id")
if err != nil {
return 0, nil, fmt.Errorf("failed system metadata lookup: %s", err)
}
ws.Add(iter.WatchCh())
var results []*structs.SystemMetadataEntry
for v := iter.Next(); v != nil; v = iter.Next() {
results = append(results, v.(*structs.SystemMetadataEntry))
}
return idx, results, nil
}
func (s *Store) SystemMetadataDelete(idx uint64, entry *structs.SystemMetadataEntry) error {
tx := s.db.WriteTxn(idx)
defer tx.Abort()
if err := systemMetadataDeleteTxn(tx, idx, entry.Key); err != nil {
return err
}
return tx.Commit()
}
func systemMetadataDeleteTxn(tx *txn, idx uint64, key string) error {
// Try to retrieve the existing system metadata.
existing, err := tx.First(systemMetadataTableName, "id", key)
if err != nil {
return fmt.Errorf("failed system metadata lookup: %s", err)
}
if existing == nil {
return nil
}
// Delete the system metadata from the DB and update the index.
if err := tx.Delete(systemMetadataTableName, existing); err != nil {
return fmt.Errorf("failed removing system metadata: %s", err)
}
if err := tx.Insert("index", &IndexEntry{systemMetadataTableName, idx}); err != nil {
return fmt.Errorf("failed updating index: %s", err)
}
return nil
}