363b616908
Not all clients and systems can support SPDY protocols. This commit adds support for two new websocket protocols, one to handle streaming of pod logs from a pod, and the other to allow exec to be tunneled over websocket. Browser support for chunked encoding is still poor, and web consoles that wish to show pod logs may need to make compromises to display the output. The /pods/<name>/log endpoint now supports websocket upgrade to the 'binary.k8s.io' subprotocol, which sends chunks of logs as binary to the client. Messages are written as logs are streamed from the container daemon, so flushing should be unaffected. Browser support for raw communication over SDPY is not possible, and some languages lack libraries for it and HTTP/2. The Kubelet supports upgrade to WebSocket instead of SPDY, and will multiplex STDOUT/IN/ERR over websockets by prepending each binary message with a single byte representing the channel (0 for IN, 1 for OUT, and 2 for ERR). Because framing on WebSockets suffers from head-of-line blocking, clients and other server code should ensure that no particular stream blocks. An alternative subprotocol 'base64.channel.k8s.io' base64 encodes the body and uses '0'-'9' to represent the channel for ease of use in browsers.
22 lines
884 B
Go
22 lines
884 B
Go
/*
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Copyright 2015 The Kubernetes Authors All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Package wsstream contains utilities for streaming content over WebSockets.
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// The Conn type allows callers to multiplex multiple read/write channels over
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// a single websocket. The Reader type allows an io.Reader to be copied over
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// a websocket channel as binary content.
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package wsstream
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