/
reader.go
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/
reader.go
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/*
* Tencent is pleased to support the open source community by making TKEStack
* available.
*
* Copyright (C) 2012-2019 Tencent. All Rights Reserved.
*
* 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
*
* https://opensource.org/licenses/Apache-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 OF ANY KIND, either express or implied. See the License for the
* specific language governing permissions and limitations under the License.
*/
package webtty
import (
"io"
)
// readerWrapper delegates to an io.Reader so that only the io.Reader interface is implemented,
// to keep io.Copy from doing things we don't want when copying from the reader to the data stream.
//
// If the Stdin io.Reader provided to remotecommand implements a WriteTo function (like bytes.Buffer does[1]),
// io.Copy calls that method[2] to attempt to write the entire buffer to the stream in one call.
// That results in an oversized call to spdystream.Stream#Write [3],
// which results in a single oversized data frame[4] that is too large.
//
// [1] https://golang.org/pkg/bytes/#Buffer.WriteTo
// [2] https://golang.org/pkg/io/#Copy
// [3] https://github.com/kubernetes/kubernetes/blob/90295640ef87db9daa0144c5617afe889e7992b2/vendor/github.com/docker/spdystream/stream.go#L66-L73
// [4] https://github.com/kubernetes/kubernetes/blob/90295640ef87db9daa0144c5617afe889e7992b2/vendor/github.com/docker/spdystream/spdy/write.go#L302-L304
type readerWrapper struct {
reader io.Reader
}
func (r readerWrapper) Read(p []byte) (int, error) {
return r.reader.Read(p)
}