mirror of https://github.com/knative/func.git
96 lines
2.5 KiB
Go
96 lines
2.5 KiB
Go
// Copyright 2018 Netflix, Inc.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package expect
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import (
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"io"
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"os"
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"time"
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)
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// PassthroughPipe is pipes data from a io.Reader and allows setting a read
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// deadline. If a timeout is reached the error is returned, otherwise the error
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// from the provided io.Reader is returned is passed through instead.
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type PassthroughPipe struct {
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reader *os.File
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errC chan error
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}
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// NewPassthroughPipe returns a new pipe for a io.Reader that passes through
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// non-timeout errors.
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func NewPassthroughPipe(reader io.Reader) (*PassthroughPipe, error) {
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pipeReader, pipeWriter, err := os.Pipe()
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if err != nil {
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return nil, err
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}
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errC := make(chan error, 1)
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go func() {
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defer close(errC)
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_, readerErr := io.Copy(pipeWriter, reader)
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if readerErr == nil {
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// io.Copy reads from reader until EOF, and a successful Copy returns
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// err == nil. We set it back to io.EOF to surface the error to Expect.
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readerErr = io.EOF
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}
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// Closing the pipeWriter will unblock the pipeReader.Read.
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err = pipeWriter.Close()
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if err != nil {
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// If we are unable to close the pipe, and the pipe isn't already closed,
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// the caller will hang indefinitely.
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panic(err)
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return
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}
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// When an error is read from reader, we need it to passthrough the err to
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// callers of (*PassthroughPipe).Read.
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errC <- readerErr
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}()
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return &PassthroughPipe{
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reader: pipeReader,
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errC: errC,
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}, nil
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}
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func (pp *PassthroughPipe) Read(p []byte) (n int, err error) {
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n, err = pp.reader.Read(p)
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if err != nil {
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if os.IsTimeout(err) {
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return n, err
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}
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// If the pipe is closed, this is the second time calling Read on
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// PassthroughPipe, so just return the error from the os.Pipe io.Reader.
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perr, ok := <-pp.errC
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if !ok {
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return n, err
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}
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return n, perr
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}
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return n, nil
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}
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func (pp *PassthroughPipe) Close() error {
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return pp.reader.Close()
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}
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func (pp *PassthroughPipe) SetReadDeadline(t time.Time) error {
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return pp.reader.SetReadDeadline(t)
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}
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