refactor: only use shaping dialer for ndt7 and dash (#754)

See https://github.com/ooni/probe/issues/2112 for context.

While there, run `go fix -fix buildtag ./...`

internal/engine/experiment/dash/dash.go

@@ -259,8 +259,14 @@ func (m Measurer) Run(
 	httpClient := &http.Client{
 		Transport: netx.NewHTTPTransport(netx.Config{
 			ContextByteCounting: true,
-			DialSaver:           saver,
-			Logger:              sess.Logger(),
+			// Implements shaping if the user builds using `-tags shaping`
+			// See https://github.com/ooni/probe/issues/2112
+			Dialer: netxlite.NewMaybeShapingDialer(netx.NewDialer(netx.Config{
+				ContextByteCounting: true,
+				DialSaver:           saver,
+				Logger:              sess.Logger(),
+			})),
+			Logger: sess.Logger(),
 		}),
 	}
 	defer httpClient.CloseIdleConnections()

internal/engine/experiment/ndt7/dial.go

@@ -42,6 +42,9 @@ func (mgr dialManager) dialWithTestName(ctx context.Context, testName string) (*
 		Logger:              mgr.logger,
 		ProxyURL:            mgr.proxyURL,
 	}, reso)
+	// Implements shaping if the user builds using `-tags shaping`
+	// See https://github.com/ooni/probe/issues/2112
+	dlr = netxlite.NewMaybeShapingDialer(dlr)
 	// We force using our bundled CA pool, which should fix
 	// https://github.com/ooni/probe/issues/2031
 	tlsConfig := &tls.Config{

internal/engine/netx/dialer/dialer.go

@@ -67,6 +67,5 @@ func New(config *Config, resolver model.Resolver) model.Dialer {
 	if config.ContextByteCounting {
 		d = &byteCounterDialer{Dialer: d}
 	}
-	d = &shapingDialer{Dialer: d}
 	return d
 }

internal/engine/netx/dialer/dialer_test.go

@@ -18,11 +18,7 @@ func TestNewCreatesTheExpectedChain(t *testing.T) {
 		ProxyURL:            &url.URL{},
 		ReadWriteSaver:      saver,
 	}, netxlite.DefaultResolver)
-	shd, ok := dlr.(*shapingDialer)
-	if !ok {
-		t.Fatal("not a shapingDialer")
-	}
-	bcd, ok := shd.Dialer.(*byteCounterDialer)
+	bcd, ok := dlr.(*byteCounterDialer)
 	if !ok {
 		t.Fatal("not a byteCounterDialer")
 	}

internal/engine/netx/dialer/shaping_disabled.go

@@ -1,24 +0,0 @@
-//go:build !shaping
-// +build !shaping
-
-package dialer
-
-import (
-	"context"
-	"net"
-
-	"github.com/ooni/probe-cli/v3/internal/model"
-)
-
-// shapingDialer ensures we don't use too much bandwidth
-// when using integration tests at GitHub. To select
-// the implementation with shaping use `-tags shaping`.
-type shapingDialer struct {
-	model.Dialer
-}
-
-// DialContext implements Dialer.DialContext
-func (d *shapingDialer) DialContext(
-	ctx context.Context, network, address string) (net.Conn, error) {
-	return d.Dialer.DialContext(ctx, network, address)
-}

internal/engine/netx/dialer/shaping_enabled.go

@@ -1,43 +0,0 @@
-//go:build shaping
-// +build shaping
-
-package dialer
-
-import (
-	"context"
-	"net"
-	"time"
-
-	"github.com/ooni/probe-cli/v3/internal/model"
-)
-
-// shapingDialer ensures we don't use too much bandwidth
-// when using integration tests at GitHub. To select
-// the implementation with shaping use `-tags shaping`.
-type shapingDialer struct {
-	model.Dialer
-}
-
-// DialContext implements Dialer.DialContext
-func (d *shapingDialer) DialContext(
-	ctx context.Context, network, address string) (net.Conn, error) {
-	conn, err := d.Dialer.DialContext(ctx, network, address)
-	if err != nil {
-		return nil, err
-	}
-	return &shapingConn{Conn: conn}, nil
-}
-
-type shapingConn struct {
-	net.Conn
-}
-
-func (c *shapingConn) Read(p []byte) (int, error) {
-	time.Sleep(100 * time.Millisecond)
-	return c.Conn.Read(p)
-}
-
-func (c *shapingConn) Write(p []byte) (int, error) {
-	time.Sleep(100 * time.Millisecond)
-	return c.Conn.Write(p)
-}

internal/engine/netx/dialer/shaping_test.go

@@ -1,22 +0,0 @@
-package dialer
-
-import (
-	"net/http"
-	"testing"
-
-	"github.com/ooni/probe-cli/v3/internal/netxlite"
-)
-
-func TestShapingDialerGood(t *testing.T) {
-	d := &shapingDialer{Dialer: netxlite.DefaultDialer}
-	txp := &http.Transport{DialContext: d.DialContext}
-	client := &http.Client{Transport: txp}
-	resp, err := client.Get("https://www.google.com/")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if resp == nil {
-		t.Fatal("expected nil response here")
-	}
-	resp.Body.Close()
-}

internal/engine/session_nopsiphon.go

@@ -1,5 +1,4 @@
 //go:build !ooni_psiphon_config
-// +build !ooni_psiphon_config
 
 package engine
 

internal/engine/session_nopsiphon_test.go

@@ -1,5 +1,4 @@
 //go:build !ooni_psiphon_config
-// +build !ooni_psiphon_config
 
 package engine
 

internal/engine/session_psiphon.go

@@ -1,5 +1,4 @@
 //go:build ooni_psiphon_config
-// +build ooni_psiphon_config
 
 package engine
 

internal/engine/session_psiphon_test.go

@@ -1,5 +1,4 @@
 //go:build ooni_psiphon_config
-// +build ooni_psiphon_config
 
 package engine