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
75 lines
2.0 KiB
Go
75 lines
2.0 KiB
Go
package dash
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import (
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"context"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"time"
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)
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type downloadDeps interface {
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HTTPClient() *http.Client
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NewHTTPRequest(method string, url string, body io.Reader) (*http.Request, error)
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ReadAllContext(ctx context.Context, r io.Reader) ([]byte, error)
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Scheme() string
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UserAgent() string
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}
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type downloadConfig struct {
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authorization string
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begin time.Time
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currentRate int64
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deps downloadDeps
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elapsedTarget int64
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fqdn string
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}
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type downloadResult struct {
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elapsed float64
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received int64
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requestTicks float64
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serverURL string
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timestamp int64
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}
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func download(ctx context.Context, config downloadConfig) (downloadResult, error) {
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nbytes := (config.currentRate * 1000 * config.elapsedTarget) >> 3
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var URL url.URL
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URL.Scheme = config.deps.Scheme()
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URL.Host = config.fqdn
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URL.Path = fmt.Sprintf("%s%d", downloadPath, nbytes)
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req, err := config.deps.NewHTTPRequest("GET", URL.String(), nil)
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var result downloadResult
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if err != nil {
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return result, err
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}
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result.serverURL = URL.String()
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req.Header.Set("User-Agent", config.deps.UserAgent())
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req.Header.Set("Authorization", config.authorization)
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savedTicks := time.Now()
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resp, err := config.deps.HTTPClient().Do(req.WithContext(ctx))
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if err != nil {
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return result, err
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}
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if resp.StatusCode != 200 {
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return result, errHTTPRequestFailed
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}
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defer resp.Body.Close()
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data, err := config.deps.ReadAllContext(ctx, resp.Body)
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if err != nil {
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return result, err
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}
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// Implementation note: MK contains a comment that says that Neubot uses
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// the elapsed time since when we start receiving the response but it
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// turns out that Neubot and MK do the same. So, we do what they do. At
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// the same time, we are currently not able to include the overhead that
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// is caused by HTTP headers etc. So, we're a bit less precise.
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result.elapsed = time.Since(savedTicks).Seconds()
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result.received = int64(len(data))
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result.requestTicks = savedTicks.Sub(config.begin).Seconds()
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result.timestamp = time.Now().Unix()
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return result, nil
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}
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