refactor: move tracex outside of engine/netx (#782)

* refactor: move tracex outside of engine/netx

Consistently with https://github.com/ooni/probe/issues/2121 and
https://github.com/ooni/probe/issues/2115, we can now move tracex
outside of engine/netx. The main reason why this makes sense now
is that the package is now changed significantly from the one
that we imported from ooni/probe-engine.

We have improved its implementation, which had not been touched
significantly for quite some time, and converted it to unit
testing. I will document tomorrow some extra work I'd like to
do with this package but likely could not do $soon.

* go fmt

* regen tutorials

internal/cmd/oohelperd/internal/webconnectivity/dns.go

@@ -5,9 +5,9 @@ import (
 	"sync"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 // newfailure is a convenience shortcut to save typing

internal/cmd/oohelperd/internal/webconnectivity/http.go

@@ -8,8 +8,8 @@ import (
 	"sync"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 // CtrlHTTPResponse is the result of the HTTP check performed by

internal/engine/experiment/dash/dash.go

@@ -15,10 +15,10 @@ import (
 
 	"github.com/montanaflynn/stats"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/humanize"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/dash/dash_test.go

@@ -12,8 +12,8 @@ import (
 	"github.com/apex/log"
 	"github.com/montanaflynn/stats"
 	"github.com/ooni/probe-cli/v3/internal/engine/mockable"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestRunnerLoopLocateFailure(t *testing.T) {

internal/engine/experiment/dnscheck/dnscheck.go

@@ -16,9 +16,9 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/atomicx"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/urlgetter"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/fbmessenger/fbmessenger_test.go

@@ -10,9 +10,9 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/fbmessenger"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/urlgetter"
 	"github.com/ooni/probe-cli/v3/internal/engine/mockable"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestNewExperimentMeasurer(t *testing.T) {

internal/engine/experiment/hhfm/hhfm.go

@@ -15,10 +15,10 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/urlgetter"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 	"github.com/ooni/probe-cli/v3/internal/randx"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/hhfm/hhfm_test.go

@@ -16,9 +16,9 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/hhfm"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/urlgetter"
 	"github.com/ooni/probe-cli/v3/internal/engine/mockable"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestNewExperimentMeasurer(t *testing.T) {

internal/engine/experiment/hirl/hirl.go

@@ -12,10 +12,10 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 	"github.com/ooni/probe-cli/v3/internal/randx"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/hirl/hirl_test.go

@@ -10,9 +10,9 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/hirl"
 	"github.com/ooni/probe-cli/v3/internal/engine/mockable"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestNewExperimentMeasurer(t *testing.T) {

internal/engine/experiment/quicping/quicping.go

@@ -17,9 +17,9 @@ import (
 
 	_ "crypto/sha256"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 // A connectionID in QUIC

internal/engine/experiment/riseupvpn/riseupvpn.go

@@ -10,9 +10,9 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/urlgetter"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/riseupvpn/riseupvpn_test.go

@@ -15,9 +15,9 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/riseupvpn"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/urlgetter"
 	"github.com/ooni/probe-cli/v3/internal/engine/mockable"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/stunreachability/stunreachability.go

@@ -12,9 +12,9 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 	"github.com/pion/stun"
 )
 

internal/engine/experiment/tlstool/tlstool.go

@@ -17,9 +17,9 @@ import (
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/tlstool/internal"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/tor/tor.go

@@ -13,12 +13,12 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/atomicx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/measurex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 	"github.com/ooni/probe-cli/v3/internal/scrubber"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/torsf/torsf.go

@@ -11,11 +11,11 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/bytecounter"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/ptx"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 	"github.com/ooni/probe-cli/v3/internal/torlogs"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 	"github.com/ooni/probe-cli/v3/internal/tunnel"
 )
 

internal/engine/experiment/urlgetter/configurer.go

@@ -9,9 +9,9 @@ import (
 	"strings"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 // The Configurer job is to construct a Configuration that can

internal/engine/experiment/urlgetter/configurer_test.go

@@ -9,8 +9,8 @@ import (
 
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/urlgetter"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestConfigurerNewConfigurationVanilla(t *testing.T) {

internal/engine/experiment/urlgetter/getter.go

@@ -6,9 +6,9 @@ import (
 	"net/url"
 	"time"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 	"github.com/ooni/probe-cli/v3/internal/tunnel"
 )
 

internal/engine/experiment/urlgetter/urlgetter.go

@@ -8,8 +8,8 @@ import (
 	"crypto/x509"
 	"time"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/vanillator/vanillator.go

@@ -10,10 +10,10 @@ import (
 	"path"
 	"time"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 	"github.com/ooni/probe-cli/v3/internal/torlogs"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 	"github.com/ooni/probe-cli/v3/internal/tunnel"
 )
 

internal/engine/experiment/webconnectivity/httpanalysis_test.go

@@ -6,8 +6,8 @@ import (
 	"github.com/google/go-cmp/cmp"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/urlgetter"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/randx"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestHTTPBodyLengthChecks(t *testing.T) {

internal/engine/experiment/webconnectivity/summary_test.go

@@ -6,8 +6,8 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestSummarize(t *testing.T) {

internal/engine/experiment/webconnectivity/webconnectivity.go

@@ -9,8 +9,8 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity/internal"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 const (

internal/engine/experiment/webconnectivity/webconnectivity_test.go

@@ -11,9 +11,9 @@ import (
 	"github.com/google/go-cmp/cmp"
 	engine "github.com/ooni/probe-cli/v3/internal/engine"
 	"github.com/ooni/probe-cli/v3/internal/engine/experiment/webconnectivity"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestNewExperimentMeasurer(t *testing.T) {

internal/engine/netx/dialer/dialer.go

@@ -7,9 +7,9 @@ import (
 	"net/url"
 
 	"github.com/ooni/probe-cli/v3/internal/bytecounter"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 // Config contains the settings for New.

internal/engine/netx/dialer/dialer_test.go

@@ -7,8 +7,8 @@ import (
 
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/internal/bytecounter"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestNewCreatesTheExpectedChain(t *testing.T) {

internal/engine/netx/integration_test.go

@@ -9,8 +9,8 @@ import (
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/internal/bytecounter"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestSuccess(t *testing.T) {

internal/engine/netx/netx.go

@@ -34,9 +34,9 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/engine/netx/dialer"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx/httptransport"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx/resolver"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 // Config contains configuration for creating a new transport. When any

internal/engine/netx/netx_test.go

@@ -13,9 +13,9 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/bytecounter"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx/resolver"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
 	"github.com/ooni/probe-cli/v3/internal/model/mocks"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 func TestNewResolverVanilla(t *testing.T) {

internal/tutorial/experiment/torsf/chapter04/README.md

@@ -38,7 +38,7 @@ The `tracex` package contains code used to format internal
 measurements representations to the OONI data format.
 
 ```Go
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 
 ```
 

internal/tutorial/experiment/torsf/chapter04/torsf.go

@@ -41,7 +41,7 @@ import (
 	// measurements representations to the OONI data format.
 	//
 	// ```Go
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/tracex"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 
 	// ```
 	//

internal/tutorial/netxlite/chapter06/README.md

@@ -53,7 +53,7 @@ creating a system resolver, except that we also need to specify the
 UDP endpoint address at which the server is listening.
 
 ```Go
-	reso := netxlite.NewResolverUDP(log.Log, dialer, *serverAddr)
+	reso := netxlite.NewParallelResolverUDP(log.Log, dialer, *serverAddr)
 ```
 
 The API we invoke is the same as in the previous chapter, though,