minio/pkg/s3select/message.go

415 lines
14 KiB
Go

/*
* Minio Cloud Storage, (C) 2019 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package s3select
import (
"bytes"
"encoding/binary"
"fmt"
"hash/crc32"
"net/http"
"strconv"
"sync/atomic"
"time"
)
// A message is in the format specified in
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-frame-overview.png
// hence the calculation is made accordingly.
func totalByteLength(headerLength, payloadLength int) int {
return 4 + 4 + 4 + headerLength + payloadLength + 4
}
func genMessage(header, payload []byte) []byte {
headerLength := len(header)
payloadLength := len(payload)
totalLength := totalByteLength(headerLength, payloadLength)
buf := new(bytes.Buffer)
binary.Write(buf, binary.BigEndian, uint32(totalLength))
binary.Write(buf, binary.BigEndian, uint32(headerLength))
prelude := buf.Bytes()
binary.Write(buf, binary.BigEndian, crc32.ChecksumIEEE(prelude))
buf.Write(header)
if payload != nil {
buf.Write(payload)
}
message := buf.Bytes()
binary.Write(buf, binary.BigEndian, crc32.ChecksumIEEE(message))
return buf.Bytes()
}
// Refer genRecordsHeader().
var recordsHeader = []byte{
13, ':', 'm', 'e', 's', 's', 'a', 'g', 'e', '-', 't', 'y', 'p', 'e', 7, 0, 5, 'e', 'v', 'e', 'n', 't',
13, ':', 'c', 'o', 'n', 't', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 24, 'a', 'p', 'p', 'l', 'i', 'c', 'a', 't', 'i', 'o', 'n', '/', 'o', 'c', 't', 'e', 't', '-', 's', 't', 'r', 'e', 'a', 'm',
11, ':', 'e', 'v', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 7, 'R', 'e', 'c', 'o', 'r', 'd', 's',
}
// newRecordsMessage - creates new Records Message which can contain a single record, partial records,
// or multiple records. Depending on the size of the result, a response can contain one or more of these messages.
//
// Header specification
// Records messages contain three headers, as follows:
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-record.png
//
// Payload specification
// Records message payloads can contain a single record, partial records, or multiple records.
func newRecordsMessage(payload []byte) []byte {
return genMessage(recordsHeader, payload)
}
// continuationMessage - S3 periodically sends this message to keep the TCP connection open.
// These messages appear in responses at random. The client must detect the message type and process accordingly.
//
// Header specification:
// Continuation messages contain two headers, as follows:
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-cont.png
//
// Payload specification:
// Continuation messages have no payload.
var continuationMessage = []byte{
0, 0, 0, 57, // total byte-length.
0, 0, 0, 41, // headers byte-length.
139, 161, 157, 242, // prelude crc.
13, ':', 'm', 'e', 's', 's', 'a', 'g', 'e', '-', 't', 'y', 'p', 'e', 7, 0, 5, 'e', 'v', 'e', 'n', 't', // headers.
11, ':', 'e', 'v', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 4, 'C', 'o', 'n', 't', // headers.
156, 134, 74, 13, // message crc.
}
// Refer genProgressHeader().
var progressHeader = []byte{
13, ':', 'm', 'e', 's', 's', 'a', 'g', 'e', '-', 't', 'y', 'p', 'e', 7, 0, 5, 'e', 'v', 'e', 'n', 't',
13, ':', 'c', 'o', 'n', 't', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 8, 't', 'e', 'x', 't', '/', 'x', 'm', 'l',
11, ':', 'e', 'v', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 8, 'P', 'r', 'o', 'g', 'r', 'e', 's', 's',
}
// newProgressMessage - creates new Progress Message. S3 periodically sends this message, if requested.
// It contains information about the progress of a query that has started but has not yet completed.
//
// Header specification:
// Progress messages contain three headers, as follows:
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-progress.png
//
// Payload specification:
// Progress message payload is an XML document containing information about the progress of a request.
// * BytesScanned => Number of bytes that have been processed before being uncompressed (if the file is compressed).
// * BytesProcessed => Number of bytes that have been processed after being uncompressed (if the file is compressed).
// * BytesReturned => Current number of bytes of records payload data returned by S3.
//
// For uncompressed files, BytesScanned and BytesProcessed are equal.
//
// Example:
//
// <?xml version="1.0" encoding="UTF-8"?>
// <Progress>
// <BytesScanned>512</BytesScanned>
// <BytesProcessed>1024</BytesProcessed>
// <BytesReturned>1024</BytesReturned>
// </Progress>
//
func newProgressMessage(bytesScanned, bytesProcessed, bytesReturned int64) []byte {
payload := []byte(`<?xml version="1.0" encoding="UTF-8"?><Progress><BytesScanned>` +
strconv.FormatInt(bytesScanned, 10) + `</BytesScanned><BytesProcessed>` +
strconv.FormatInt(bytesProcessed, 10) + `</BytesProcessed><BytesReturned>` +
strconv.FormatInt(bytesReturned, 10) + `</BytesReturned></Stats>`)
return genMessage(progressHeader, payload)
}
// Refer genStatsHeader().
var statsHeader = []byte{
13, ':', 'm', 'e', 's', 's', 'a', 'g', 'e', '-', 't', 'y', 'p', 'e', 7, 0, 5, 'e', 'v', 'e', 'n', 't',
13, ':', 'c', 'o', 'n', 't', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 8, 't', 'e', 'x', 't', '/', 'x', 'm', 'l',
11, ':', 'e', 'v', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 5, 'S', 't', 'a', 't', 's',
}
// newStatsMessage - creates new Stats Message. S3 sends this message at the end of the request.
// It contains statistics about the query.
//
// Header specification:
// Stats messages contain three headers, as follows:
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-stats.png
//
// Payload specification:
// Stats message payload is an XML document containing information about a request's stats when processing is complete.
// * BytesScanned => Number of bytes that have been processed before being uncompressed (if the file is compressed).
// * BytesProcessed => Number of bytes that have been processed after being uncompressed (if the file is compressed).
// * BytesReturned => Total number of bytes of records payload data returned by S3.
//
// For uncompressed files, BytesScanned and BytesProcessed are equal.
//
// Example:
//
// <?xml version="1.0" encoding="UTF-8"?>
// <Stats>
// <BytesScanned>512</BytesScanned>
// <BytesProcessed>1024</BytesProcessed>
// <BytesReturned>1024</BytesReturned>
// </Stats>
func newStatsMessage(bytesScanned, bytesProcessed, bytesReturned int64) []byte {
payload := []byte(`<?xml version="1.0" encoding="UTF-8"?><Stats><BytesScanned>` +
strconv.FormatInt(bytesScanned, 10) + `</BytesScanned><BytesProcessed>` +
strconv.FormatInt(bytesProcessed, 10) + `</BytesProcessed><BytesReturned>` +
strconv.FormatInt(bytesReturned, 10) + `</BytesReturned></Stats>`)
return genMessage(statsHeader, payload)
}
// endMessage - indicates that the request is complete, and no more messages will be sent.
// You should not assume that the request is complete until the client receives an End message.
//
// Header specification:
// End messages contain two headers, as follows:
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-end.png
//
// Payload specification:
// End messages have no payload.
var endMessage = []byte{
0, 0, 0, 56, // total byte-length.
0, 0, 0, 40, // headers byte-length.
193, 198, 132, 212, // prelude crc.
13, ':', 'm', 'e', 's', 's', 'a', 'g', 'e', '-', 't', 'y', 'p', 'e', 7, 0, 5, 'e', 'v', 'e', 'n', 't', // headers.
11, ':', 'e', 'v', 'e', 'n', 't', '-', 't', 'y', 'p', 'e', 7, 0, 3, 'E', 'n', 'd', // headers.
207, 151, 211, 146, // message crc.
}
// newErrorMessage - creates new Request Level Error Message. S3 sends this message if the request failed for any reason.
// It contains the error code and error message for the failure. If S3 sends a RequestLevelError message,
// it doesn't send an End message.
//
// Header specification:
// Request-level error messages contain three headers, as follows:
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-error.png
//
// Payload specification:
// Request-level error messages have no payload.
func newErrorMessage(errorCode, errorMessage []byte) []byte {
buf := new(bytes.Buffer)
buf.Write([]byte{13, ':', 'm', 'e', 's', 's', 'a', 'g', 'e', '-', 't', 'y', 'p', 'e', 7, 0, 5, 'e', 'r', 'r', 'o', 'r'})
buf.Write([]byte{14, ':', 'e', 'r', 'r', 'o', 'r', '-', 'm', 'e', 's', 's', 'a', 'g', 'e', 7})
binary.Write(buf, binary.BigEndian, uint16(len(errorMessage)))
buf.Write(errorMessage)
buf.Write([]byte{11, ':', 'e', 'r', 'r', 'o', 'r', '-', 'c', 'o', 'd', 'e', 7})
binary.Write(buf, binary.BigEndian, uint16(len(errorCode)))
buf.Write(errorCode)
return genMessage(buf.Bytes(), nil)
}
// NewErrorMessage - creates new Request Level Error Message specified in
// https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectSELECTContent.html.
func NewErrorMessage(errorCode, errorMessage string) []byte {
return newErrorMessage([]byte(errorCode), []byte(errorMessage))
}
type messageWriter struct {
writer http.ResponseWriter
getProgressFunc func() (int64, int64)
bytesReturned int64
payloadBuffer []byte
payloadBufferIndex int
dataCh chan []byte
doneCh chan struct{}
closeCh chan struct{}
stopped uint32
closed uint32
}
func (writer *messageWriter) write(data []byte) bool {
if _, err := writer.writer.Write(data); err != nil {
return false
}
writer.writer.(http.Flusher).Flush()
return true
}
func (writer *messageWriter) start() {
keepAliveTicker := time.NewTicker(1 * time.Second)
var progressTicker *time.Ticker
if writer.getProgressFunc != nil {
progressTicker = time.NewTicker(1 * time.Minute)
}
go func() {
quitFlag := 0
for quitFlag == 0 {
if progressTicker == nil {
select {
case data, ok := <-writer.dataCh:
if !ok {
quitFlag = 1
break
}
if !writer.write(data) {
quitFlag = 1
}
case <-writer.doneCh:
quitFlag = 2
case <-keepAliveTicker.C:
if !writer.write(continuationMessage) {
quitFlag = 1
}
}
} else {
select {
case data, ok := <-writer.dataCh:
if !ok {
quitFlag = 1
break
}
if !writer.write(data) {
quitFlag = 1
}
case <-writer.doneCh:
quitFlag = 2
case <-keepAliveTicker.C:
if !writer.write(continuationMessage) {
quitFlag = 1
}
case <-progressTicker.C:
bytesScanned, bytesProcessed := writer.getProgressFunc()
bytesReturned := atomic.LoadInt64(&writer.bytesReturned)
if !writer.write(newProgressMessage(bytesScanned, bytesProcessed, bytesReturned)) {
quitFlag = 1
}
}
}
}
atomic.StoreUint32(&writer.stopped, 1)
close(writer.closeCh)
keepAliveTicker.Stop()
if progressTicker != nil {
progressTicker.Stop()
}
if quitFlag == 2 {
for data := range writer.dataCh {
if _, err := writer.writer.Write(data); err != nil {
break
}
}
}
}()
}
func (writer *messageWriter) close() {
if atomic.SwapUint32(&writer.closed, 1) == 0 {
close(writer.doneCh)
for range writer.closeCh {
close(writer.dataCh)
}
}
}
const (
bufLength = maxRecordSize
)
// collectRecord - collects records into a buffer, and when it is
// full, sends a message with the collected payload.
func (writer *messageWriter) collectRecord(data []byte) (err error) {
freeSpace := bufLength - writer.payloadBufferIndex
if len(data) > freeSpace {
err = writer.FlushRecords()
if err != nil {
return err
}
}
copy(writer.payloadBuffer[writer.payloadBufferIndex:], data)
writer.payloadBufferIndex += len(data)
return nil
}
func (writer *messageWriter) send(data []byte) error {
err := func() error {
if atomic.LoadUint32(&writer.stopped) == 1 {
return fmt.Errorf("writer already closed")
}
select {
case writer.dataCh <- data:
case <-writer.doneCh:
return fmt.Errorf("closed writer")
}
return nil
}()
if err != nil {
writer.close()
}
return err
}
func (writer *messageWriter) SendRecords(payload []byte) error {
return writer.collectRecord(payload)
}
func (writer *messageWriter) FlushRecords() (err error) {
err = writer.send(newRecordsMessage(writer.payloadBuffer[0:writer.payloadBufferIndex]))
if err != nil {
return err
}
atomic.AddInt64(&writer.bytesReturned, int64(writer.payloadBufferIndex))
writer.payloadBufferIndex = 0
return nil
}
func (writer *messageWriter) SendStats(bytesScanned, bytesProcessed int64) error {
bytesReturned := atomic.LoadInt64(&writer.bytesReturned)
err := writer.send(newStatsMessage(bytesScanned, bytesProcessed, bytesReturned))
if err != nil {
return err
}
err = writer.send(endMessage)
writer.close()
return err
}
func (writer *messageWriter) SendError(errorCode, errorMessage string) error {
err := writer.send(newErrorMessage([]byte(errorCode), []byte(errorMessage)))
if err == nil {
writer.close()
}
return err
}
func newMessageWriter(w http.ResponseWriter, getProgressFunc func() (bytesScanned, bytesProcessed int64)) *messageWriter {
writer := &messageWriter{
writer: w,
getProgressFunc: getProgressFunc,
payloadBuffer: make([]byte, bufLength),
dataCh: make(chan []byte),
doneCh: make(chan struct{}),
closeCh: make(chan struct{}),
}
writer.start()
return writer
}