cyberark/secretless-broker

package protocol

import (
    "fmt"
)

/* MySQL Error Codes */
const (
    CRUnknownError  = 2000
    malformedPacket = 2027
    // CRSSLConnectionError is CR_SSL_CONNECTION_ERROR
    CRSSLConnectionError = 2026
)

const (
    // ErrorCodeInternalError indicates an unspecified internal error.
    ErrorCodeInternalError = "HY000"
)

// ErrorContainer interface makes it possible
// to have Go errors that can contain rich protocol specific information
// and have the smarts to encode themselves into a MYSQL error packet
type ErrorContainer interface {
    GetPacket() []byte
}

// Error is a MySQL processing error.
type Error struct {
    Code     uint16
    SQLState string
    Message  string
}

// NewGenericError returns a MySQL protocol specific error, to handle cases
// that don't fit neatly into the MySQL code categories.  This makes sense,
// since a Go error, eg, is not a true "protocol" error but instead something
// resulting from Secretless's role as a proxy, which MySQL is unaware of.
//
// That said, we should try to use MySQL specific error codes wherever we
// can, so that client error messages will be more meaningful.
//
// TODO: Replace instances of generic error with specific MySQL error codes.
func NewGenericError(goErr error) Error {
    return Error{
        Code:     CRUnknownError,
        SQLState: ErrorCodeInternalError,
        Message:  goErr.Error(),
    }
}

// ErrNoTLS is a MySQL protocol error raised when SSL is required but the
// server doesn't support it.
var ErrNoTLS = Error{
    Code:     CRSSLConnectionError,
    SQLState: ErrorCodeInternalError,
    Message:  "SSL connection error: SSL is required but the server doesn't support it",
}

func (e Error) Error() string {
    return fmt.Sprintf("ERROR: %v (%s): %s", e.Code, e.SQLState, e.Message)
}

// GetPacket formats an Error into a protocol message.
// https://dev.mysql.com/doc/dev/mysql-server/latest/page_protocol_basic_err_packet.html
func (e Error) GetPacket() []byte {
    data := make([]byte, 4, 4+1+2+1+5+len(e.Message))
    data = append(data, 0xff)
    data = append(data, byte(e.Code), byte(e.Code>>8))

    // TODO: for client41
    data = append(data, '#')
    data = append(data, e.SQLState...)
    data = append(data, e.Message...)

    // prepare message
    length := len(data) - 4
    data[0] = byte(length)
    data[1] = byte(length >> 8)
    data[2] = byte(length >> 16)
    //sequenceID defaults to 0
    //expected to be overwritten by writer
    data[3] = byte(0)

    return data
}