func (s *Server) execute(tx bool, stmts []string) ([]FailedSqlStmt, error) {
var failures = make([]FailedSqlStmt, 0)
if tx {
log.Trace("Transaction requested")
s.metrics.executeTxReceived.Inc(1)
_, err := s.raftServer.Do(command.NewTransactionExecuteCommandSet(stmts))
if err != nil {
log.Tracef("Transaction failed: %s", err.Error())
s.metrics.executeFail.Inc(1)
failures = append(failures, FailedSqlStmt{stmts[0], err.Error()})
} else {
s.metrics.executeSuccess.Inc(1)
}
} else {
log.Trace("No transaction requested")
for i := range stmts {
_, err := s.raftServer.Do(command.NewExecuteCommand(stmts[i]))
if err != nil {
log.Tracef("Execute statement %s failed: %s", stmts[i], err.Error())
s.metrics.executeFail.Inc(1)
failures = append(failures, FailedSqlStmt{stmts[i], err.Error()})
} else {
s.metrics.executeSuccess.Inc(1)
}
}
}
return failures, nil
}
// Recovery restores the state of the database using the given data.
func (d *DbStateMachine) Recovery(b []byte) error {
log.Tracef("Restoring database state to path: %s", d.dbpath)
err := ioutil.WriteFile(d.dbpath, b, os.ModePerm)
if err != nil {
log.Errorf("Failed to recover state: %s", err.Error())
return err
}
log.Tracef("Database restored successfully to %s", d.dbpath)
return nil
}
// Save captures the state of the database. The caller must ensure that
// no transaction is taking place during this call.
//
// http://sqlite.org/howtocorrupt.html states it is safe to do this
// as long as no transaction is in progress.
func (d *DbStateMachine) Save() ([]byte, error) {
log.Tracef("Capturing database state from path: %s", d.dbpath)
b, err := ioutil.ReadFile(d.dbpath)
if err != nil {
log.Errorf("Failed to save state: %s", err.Error())
return nil, err
}
log.Tracef("Database state successfully saved to %s", d.dbpath)
return b, nil
}
func (s *Server) readHandler(w http.ResponseWriter, req *http.Request) {
log.Tracef("readHandler for URL: %s", req.URL)
s.metrics.queryReceived.Inc(1)
var failures = make([]FailedSqlStmt, 0)
// Get the query statement
stmt, err := stmtParam(req)
if err != nil {
log.Tracef("Bad HTTP request: %s", err.Error())
w.WriteHeader(http.StatusBadRequest)
s.metrics.queryFail.Inc(1)
return
}
startTime := time.Now()
r, err := s.db.Query(stmt)
if err != nil {
log.Tracef("Bad SQL statement: %s", err.Error())
s.metrics.queryFail.Inc(1)
failures = append(failures, FailedSqlStmt{stmt, err.Error()})
} else {
s.metrics.querySuccess.Inc(1)
}
duration := time.Since(startTime)
rr := QueryResponse{Failures: failures, Rows: r}
if e, _ := isExplain(req); e {
rr.Time = duration.String()
}
pretty, _ := isPretty(req)
var b []byte
if pretty {
b, err = json.MarshalIndent(rr, "", " ")
} else {
b, err = json.Marshal(rr)
}
if err != nil {
log.Tracef("Failed to marshal JSON data: %s", err.Error())
http.Error(w, err.Error(), http.StatusBadRequest) // Internal error actually
} else {
_, err = w.Write([]byte(b))
if err != nil {
log.Errorf("Error writting JSON data: %s", err.Error())
}
}
}
// NewDbStateMachine returns a StateMachine for capturing and restoring
// the state of an sqlite database.
func NewDbStateMachine(path string) *DbStateMachine {
d := &DbStateMachine{
dbpath: path,
}
log.Tracef("New DB state machine created with path: %s", path)
return d
}
// Open an existing database, creating it if it does not exist.
func Open(dbPath string) *DB {
log.Tracef("Opening SQLite database path at %s", dbPath)
dbc, err := sql.Open("sqlite3", dbPath)
if err != nil {
log.Error(err.Error())
return nil
}
return &DB{
dbConn: dbc,
}
}
// Apply executes a set of sqlite statements, within a transaction. All statements
// will take effect, or none.
func (c *TransactionExecuteCommandSet) Apply(server raft.Server) (interface{}, error) {
log.Tracef("Applying TransactionExecuteCommandSet of size %d", len(c.Stmts))
commitSuccess := false
db := server.Context().(*db.DB)
defer func() {
if !commitSuccess {
err := db.RollbackTransaction()
if err != nil {
log.Errorf("Failed to rollback transaction: %s", err.Error())
}
}
}()
err := db.StartTransaction()
if err != nil {
log.Errorf("Failed to start transaction: %s", err.Error())
return nil, err
}
for i := range c.Stmts {
err = db.Execute(c.Stmts[i])
if err != nil {
log.Errorf("Failed to execute statement within transaction: %s", err.Error())
return nil, err
}
}
if err = db.CommitTransaction(); err != nil {
log.Errorf("Failed to commit transaction: %s", err.Error())
return nil, err
}
commitSuccess = true
return nil, nil
}
// New creates a new database. Deletes any existing database.
func New(dbPath string) *DB {
log.Tracef("Removing any existing SQLite database at %s", dbPath)
_ = os.Remove(dbPath)
return Open(dbPath)
}
func (s *Server) writeHandler(w http.ResponseWriter, req *http.Request) {
s.mutex.Lock()
defer s.mutex.Unlock()
if s.raftServer.State() != "leader" {
s.leaderRedirect(w, req)
return
}
log.Tracef("writeHandler for URL: %s", req.URL)
s.metrics.executeReceived.Inc(1)
currentIndex := s.raftServer.CommitIndex()
count := currentIndex - s.snapConf.lastIndex
if uint64(count) > s.snapConf.snapshotAfter {
log.Info("Committed log entries snapshot threshold reached, starting snapshot")
err := s.raftServer.TakeSnapshot()
s.logSnapshot(err, currentIndex, count)
s.snapConf.lastIndex = currentIndex
s.metrics.snapshotCreated.Inc(1)
}
// Read the value from the POST body.
b, err := ioutil.ReadAll(req.Body)
if err != nil {
log.Tracef("Bad HTTP request: %s", err.Error())
s.metrics.executeFail.Inc(1)
w.WriteHeader(http.StatusBadRequest)
return
}
stmts := strings.Split(string(b), ";")
if stmts[len(stmts)-1] == "" {
stmts = stmts[:len(stmts)-1]
}
log.Tracef("Execute statement contains %d commands", len(stmts))
if len(stmts) == 0 {
log.Trace("No database execute commands supplied")
s.metrics.executeFail.Inc(1)
w.WriteHeader(http.StatusBadRequest)
return
}
transaction, _ := isTransaction(req)
startTime := time.Now()
failures, err := s.execute(transaction, stmts)
if err != nil {
log.Errorf("Database mutation failed: %s", err.Error())
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
duration := time.Since(startTime)
wr := StmtResponse{Failures: failures}
if e, _ := isExplain(req); e {
wr.Time = duration.String()
}
pretty, _ := isPretty(req)
if pretty {
b, err = json.MarshalIndent(wr, "", " ")
} else {
b, err = json.Marshal(wr)
}
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
} else {
_, err = w.Write([]byte(b))
if err != nil {
log.Errorf("Error writting JSON data: %s", err.Error())
}
}
}
// Apply executes an sqlite statement.
func (c *ExecuteCommand) Apply(server raft.Server) (interface{}, error) {
log.Tracef("Applying ExecuteCommand: '%s'", c.Stmt)
db := server.Context().(*db.DB)
return nil, db.Execute(c.Stmt)
}
