0fdc9cafb5
* fix(all): introduce and use iox.ReadAllContext This improvement over the ioutil.ReadAll utility returns early if the context expires. This enables us to unblock stuck code in case there's censorship confounding the TCP stack. See https://github.com/ooni/probe/issues/1417. Compared to the functionality postulated in the above mentioned issue, I choose to be more generic and separate limiting the maximum body size (not implemented here) from using the context to return early when reading a body (or any other reader). After implementing iox.ReadAllContext, I made sure we always use it everywhere in the tree instead of ioutil.ReadAll. This includes many parts of the codebase where in theory we don't need iox.ReadAllContext. Though, changing all the places makes checking whether we're not using ioutil.ReadAll where we should not be using it easy: `git grep` should return no lines. * Update internal/iox/iox_test.go * fix(ndt7): treat context errors as non-errors The rationale is explained by the comment documenting reduceErr. * Update internal/engine/experiment/ndt7/download.go
48 lines
1.1 KiB
Go
48 lines
1.1 KiB
Go
// Package iox contains io extensions.
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package iox
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import (
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"context"
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"io"
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)
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// ReadAllContext reads the whole reader r in a
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// background goroutine. This function will return
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// earlier if the context is cancelled. In which case
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// we will continue reading from r in the background
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// goroutine, and we will discard the result. To stop
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// the long-running goroutine, you need to close the
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// connection bound to the r reader, if possible.
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func ReadAllContext(ctx context.Context, r io.Reader) ([]byte, error) {
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datach, errch := make(chan []byte, 1), make(chan error, 1) // buffers
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go func() {
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data, err := io.ReadAll(r)
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if err != nil {
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errch <- err
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return
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}
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datach <- data
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}()
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select {
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case data := <-datach:
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return data, nil
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case <-ctx.Done():
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return nil, ctx.Err()
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case err := <-errch:
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return nil, err
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}
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}
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// MockableReader allows to mock any io.Reader.
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type MockableReader struct {
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MockRead func(b []byte) (int, error)
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}
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// MockableReader implements an io.Reader.
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var _ io.Reader = &MockableReader{}
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// Read implements io.Reader.Read.
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func (r *MockableReader) Read(b []byte) (int, error) {
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return r.MockRead(b)
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}
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