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conn_process.go
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conn_process.go
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// Licensed to ClickHouse, Inc. under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. ClickHouse, Inc. licenses this file to you 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 clickhouse
import (
"context"
"fmt"
"io"
"github.com/ClickHouse/clickhouse-go/v2/lib/proto"
"github.com/pkg/errors"
)
type onProcess struct {
data func(*proto.Block)
logs func([]Log)
progress func(*Progress)
profileInfo func(*ProfileInfo)
profileEvents func([]ProfileEvent)
}
func (c *connect) firstBlock(ctx context.Context, on *onProcess) (*proto.Block, error) {
// if context is already timedout/cancelled — we're done
select {
case <-ctx.Done():
c.cancel()
return nil, ctx.Err()
default:
}
// do reads in background
resultCh := make(chan *proto.Block, 1)
errCh := make(chan error, 1)
go func() {
block, err := c.firstBlockImpl(ctx, on)
if err != nil {
errCh <- err
return
}
resultCh <- block
}()
// select on context or read channels (results/errors)
select {
case <-ctx.Done():
c.cancel()
return nil, ctx.Err()
case err := <-errCh:
return nil, err
case block := <-resultCh:
return block, nil
}
}
func (c *connect) firstBlockImpl(ctx context.Context, on *onProcess) (*proto.Block, error) {
c.readerMutex.Lock()
defer c.readerMutex.Unlock()
for {
if c.reader == nil {
return nil, errors.New("unexpected state: c.reader is nil")
}
packet, err := c.reader.ReadByte()
if err != nil {
return nil, err
}
switch packet {
case proto.ServerData:
return c.readData(ctx, packet, true)
case proto.ServerEndOfStream:
c.debugf("[end of stream]")
return nil, io.EOF
default:
if err := c.handle(ctx, packet, on); err != nil {
// handling error, return
return nil, err
}
// handled okay, read next byte
}
}
}
func (c *connect) process(ctx context.Context, on *onProcess) error {
// if context is already timedout/cancelled — we're done
select {
case <-ctx.Done():
c.cancel()
return ctx.Err()
default:
}
// do reads in background
errCh := make(chan error, 1)
doneCh := make(chan bool, 1)
go func() {
err := c.processImpl(ctx, on)
if err != nil {
errCh <- err
return
}
doneCh <- true
}()
// select on context or read channel (errors)
select {
case <-ctx.Done():
c.cancel()
return ctx.Err()
case err := <-errCh:
return err
case <-doneCh:
return nil
}
}
func (c *connect) processImpl(ctx context.Context, on *onProcess) error {
c.readerMutex.Lock()
defer c.readerMutex.Unlock()
for {
if c.reader == nil {
return errors.New("unexpected state: c.reader is nil")
}
packet, err := c.reader.ReadByte()
if err != nil {
return err
}
switch packet {
case proto.ServerEndOfStream:
c.debugf("[end of stream]")
return nil
}
if err := c.handle(ctx, packet, on); err != nil {
// handling error, return
return err
}
// handled okay, read next byte
}
}
func (c *connect) handle(ctx context.Context, packet byte, on *onProcess) error {
switch packet {
case proto.ServerData, proto.ServerTotals, proto.ServerExtremes:
block, err := c.readData(ctx, packet, true)
if err != nil {
return err
}
if block.Rows() != 0 && on.data != nil {
on.data(block)
}
case proto.ServerException:
return c.exception()
case proto.ServerProfileInfo:
var info proto.ProfileInfo
if err := info.Decode(c.reader, c.revision); err != nil {
return err
}
c.debugf("[profile info] %s", &info)
on.profileInfo(&info)
case proto.ServerTableColumns:
var info proto.TableColumns
if err := info.Decode(c.reader, c.revision); err != nil {
return err
}
c.debugf("[table columns]")
case proto.ServerProfileEvents:
events, err := c.profileEvents(ctx)
if err != nil {
return err
}
on.profileEvents(events)
case proto.ServerLog:
logs, err := c.logs(ctx)
if err != nil {
return err
}
on.logs(logs)
case proto.ServerProgress:
progress, err := c.progress()
if err != nil {
return err
}
c.debugf("[progress] %s", progress)
on.progress(progress)
default:
return &OpError{
Op: "process",
Err: fmt.Errorf("unexpected packet %d", packet),
}
}
return nil
}
func (c *connect) cancel() error {
c.debugf("[cancel]")
c.buffer.PutUVarInt(proto.ClientCancel)
wErr := c.flush()
// don't reuse a cancelled query as we don't drain the connection
if cErr := c.close(); cErr != nil {
return cErr
}
return wErr
}