ooni-probe-cli/internal/engine/experiment/ndt7/download.go
Simone Basso 3265bc670a
refactor(ndt7): use netxlite rather than netx (#768)
This diff required us to move some code around, but no major
change actually happened, except better tests.

While there, I also slightly refactored ndt7's implementation and
removed the ProxyURL setting, which was actually unused.

See https://github.com/ooni/probe/issues/2121
2022-05-30 23:14:07 +02:00

99 lines
2.4 KiB
Go

package ndt7
import (
"context"
"errors"
"io"
"time"
"github.com/gorilla/websocket"
"github.com/ooni/probe-cli/v3/internal/netxlite"
)
type downloadManager struct {
conn wsConn
maxMessageSize int64
maxRuntime time.Duration
measureInterval time.Duration
onJSON callbackJSON
onPerformance callbackPerformance
}
func newDownloadManager(
conn wsConn, onPerformance callbackPerformance,
onJSON callbackJSON,
) downloadManager {
return downloadManager{
conn: conn,
maxMessageSize: paramMaxMessageSize,
maxRuntime: paramMaxRuntime,
measureInterval: paramMeasureInterval,
onJSON: onJSON,
onPerformance: onPerformance,
}
}
func (mgr downloadManager) run(ctx context.Context) error {
return mgr.reduceErr(mgr.doRun(ctx))
}
// reduceErr treats as non-errors the errors caused by the context
// so that we can focus instead on network errors.
//
// This function was introduced by https://github.com/ooni/probe-cli/pull/379
// since before such a PR we did not see context interrupting
// errors when we were reading messages. Since before such a PR
// we used to return `nil` on context errors, this function is
// here to keep the previous behavior by filtering the error
// returned when reading messages, given that now reading messages
// can fail midway because we use netxlite.ReadAllContext.
func (mgr downloadManager) reduceErr(err error) error {
if errors.Is(err, context.Canceled) {
return nil
}
if errors.Is(err, context.DeadlineExceeded) {
return nil
}
return err
}
func (mgr downloadManager) doRun(ctx context.Context) error {
var total int64
start := time.Now()
if err := mgr.conn.SetReadDeadline(start.Add(mgr.maxRuntime)); err != nil {
return err
}
mgr.conn.SetReadLimit(mgr.maxMessageSize)
ticker := time.NewTicker(mgr.measureInterval)
defer ticker.Stop()
for ctx.Err() == nil {
kind, reader, err := mgr.conn.NextReader()
if err != nil {
return err
}
if kind == websocket.TextMessage {
data, err := netxlite.ReadAllContext(ctx, reader)
if err != nil {
return err
}
total += int64(len(data))
if err := mgr.onJSON(data); err != nil {
return err
}
continue
}
n, err := netxlite.CopyContext(ctx, io.Discard, reader)
if err != nil {
return err
}
total += int64(n)
select {
case now := <-ticker.C:
mgr.onPerformance(now.Sub(start), total)
default:
// NOTHING
}
}
return nil
}