feat: clearly indicate which resolver we're using (#885)

See what we documented at https://github.com/ooni/spec/pull/257

Reference issue: https://github.com/ooni/probe/issues/2238

See also the related ooni/spec PR: https://github.com/ooni/spec/pull/257

See also https://github.com/ooni/probe/issues/2237

While there, bump webconnectivity@v0.5 version because this change
has an impact onto the generated data format.

The drop in coverage is unavoidable because we've written some
tests for `measurex` to ensure we deal with DNS resolvers and transport
names correctly depending on the splitting policy we use.

(However, `measurex` is only used for the `tor` experiment and, per
the step-by-step design document, new experiments should use
`measurexlite` instead, so this is hopefully fine(TM).)

While there, fix a broken integration test that does not run in `-short` mode.

internal/measurex/dnsx.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/model"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 // WrapDNSXRoundTripper creates a new DNSXRoundTripper that
@@ -42,7 +43,7 @@ func (txp *dnsxRoundTripperDB) RoundTrip(
 	response, err := txp.DNSTransport.RoundTrip(ctx, query)
 	finished := time.Since(txp.begin).Seconds()
 	txp.db.InsertIntoDNSRoundTrip(&DNSRoundTripEvent{
-		Network:  txp.DNSTransport.Network(),
+		Network:  tracex.ResolverNetworkAdaptNames(txp.DNSTransport.Network()),
 		Address:  txp.DNSTransport.Address(),
 		Query:    txp.maybeQueryBytes(query),
 		Started:  started,

internal/measurex/dnsx_test.go

@@ -0,0 +1,47 @@
+package measurex
+
+import (
+	"context"
+	"testing"
+
+	"github.com/miekg/dns"
+	"github.com/ooni/probe-cli/v3/internal/model/mocks"
+	"github.com/ooni/probe-cli/v3/internal/netxlite"
+)
+
+func TestDNSXModifiesStdlibTransportName(t *testing.T) {
+	// See https://github.com/ooni/spec/pull/257 for more information.
+	child := netxlite.NewDNSOverGetaddrinfoTransport()
+	mx := NewMeasurerWithDefaultSettings()
+	dbout := &MeasurementDB{}
+	txp := mx.WrapDNSXRoundTripper(dbout, child)
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // we want to fail immediately
+	query := &mocks.DNSQuery{
+		MockDomain: func() string {
+			return "dns.google"
+		},
+		MockType: func() uint16 {
+			return dns.TypeANY
+		},
+		MockBytes: func() ([]byte, error) {
+			return []byte{}, nil
+		},
+		MockID: func() uint16 {
+			return 1453
+		},
+	}
+	_, _ = txp.RoundTrip(ctx, query)
+	measurement := dbout.AsMeasurement()
+	var good int
+	for _, rtinfo := range measurement.DNSRoundTrip {
+		network := rtinfo.Network
+		if network != netxlite.StdlibResolverSystem {
+			t.Fatal("unexpected network", network)
+		}
+		good++
+	}
+	if good < 1 {
+		t.Fatal("no good entry seen")
+	}
+}

internal/measurex/resolver.go

@@ -13,6 +13,7 @@ import (
 
 	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
+	"github.com/ooni/probe-cli/v3/internal/tracex"
 )
 
 // WrapResolver creates a new Resolver that saves events into the WritableDB.
@@ -105,7 +106,7 @@ func (r *resolverDB) LookupHost(ctx context.Context, domain string) ([]string, e
 func (r *resolverDB) saveLookupResults(domain string, started, finished float64,
 	err error, addrs []string, qtype string) {
 	ev := &DNSLookupEvent{
-		Network:   r.Resolver.Network(),
+		Network:   tracex.ResolverNetworkAdaptNames(r.Resolver.Network()),
 		Address:   r.Resolver.Address(),
 		Failure:   NewFailure(err),
 		Domain:    domain,
@@ -158,7 +159,7 @@ func (r *resolverDB) LookupHTTPS(ctx context.Context, domain string) (*model.HTT
 	https, err := r.Resolver.LookupHTTPS(ctx, domain)
 	finished := time.Since(r.begin).Seconds()
 	ev := &DNSLookupEvent{
-		Network:   r.Resolver.Network(),
+		Network:   tracex.ResolverNetworkAdaptNames(r.Resolver.Network()),
 		Address:   r.Resolver.Address(),
 		Domain:    domain,
 		QueryType: "HTTPS",

internal/measurex/resolver_test.go

@@ -0,0 +1,58 @@
+package measurex
+
+import (
+	"context"
+	"testing"
+
+	"github.com/ooni/probe-cli/v3/internal/model"
+	"github.com/ooni/probe-cli/v3/internal/netxlite"
+)
+
+func TestResolverModifiesStdlibResolverName(t *testing.T) {
+	// See https://github.com/ooni/spec/pull/257 for more information.
+
+	t.Run("for LookupHost", func(t *testing.T) {
+		child := netxlite.NewStdlibResolver(model.DiscardLogger)
+		mx := NewMeasurerWithDefaultSettings()
+		dbout := &MeasurementDB{}
+		txp := mx.WrapResolver(dbout, child)
+		ctx, cancel := context.WithCancel(context.Background())
+		cancel() // we want to fail immediately
+		_, _ = txp.LookupHost(ctx, "dns.google")
+		measurement := dbout.AsMeasurement()
+		var good int
+		for _, rtinfo := range measurement.LookupHost {
+			network := rtinfo.Network
+			if network != netxlite.StdlibResolverSystem {
+				t.Fatal("unexpected network", network)
+			}
+			good++
+		}
+		if good < 1 {
+			t.Fatal("no good entry seen")
+		}
+	})
+
+	t.Run("for LookupHTTPS", func(t *testing.T) {
+		child := netxlite.NewStdlibResolver(model.DiscardLogger)
+		mx := NewMeasurerWithDefaultSettings()
+		dbout := &MeasurementDB{}
+		txp := mx.WrapResolver(dbout, child)
+		ctx, cancel := context.WithCancel(context.Background())
+		cancel() // we want to fail immediately
+		_, _ = txp.LookupHTTPS(ctx, "dns.google")
+		measurement := dbout.AsMeasurement()
+		var good int
+		for _, rtinfo := range measurement.LookupHTTPSSvc {
+			network := rtinfo.Network
+			if network != netxlite.StdlibResolverSystem {
+				t.Fatal("unexpected network", network)
+			}
+			good++
+		}
+		if good < 1 {
+			t.Fatal("no good entry seen")
+		}
+	})
+
+}