Pull request 253: 324 refactor upstream

Merge in GO/dnsproxy from 324-refactor-upstream to master

Closes #324.

Squashed commit of the following:

commit cceed0b
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 18 15:48:15 2023 +0300

    proxy: fix check

commit 3b0a231
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 18 13:55:34 2023 +0300

    all: imp tests again

commit eba1be6
Merge: c4e73af 5864a87
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Apr 17 19:20:29 2023 +0300

    Merge branch 'master' into 324-refactor-upstream

commit c4e73af
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Apr 17 15:00:58 2023 +0300

    upstream: fix tests

commit 1bc8d36
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Apr 17 14:46:16 2023 +0300

    all: imp code, docs

commit c9ec31f
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 14 19:48:33 2023 +0300

    upstream: imp logging, field alignment

commit 418df4c
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 14 19:08:15 2023 +0300

    upstream: imp code

commit 92df453
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 14 18:45:54 2023 +0300

    upstream: bootstrap plain dns

commit 44c9e38
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 14 14:07:10 2023 +0300

    upstream: fix tests, imp docs

commit 4c0959d
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 14 12:30:00 2023 +0300

    upstream: imp code, docs

commit 3381917
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Apr 12 21:27:55 2023 +0300

    upstream: refactor doq

commit 0bd11e1
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Apr 12 21:01:30 2023 +0300

    upstream: refactor doh

commit 29ce52f
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 19:34:37 2023 +0300

    all: refactor dot

commit 6c9d87e
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 01:34:41 2023 +0300

    upstream: refactor dnscrypt, imp code

commit f111729
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Apr 11 19:53:16 2023 +0300

    all: imp code, docs

commit 726d937
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Apr 10 17:06:35 2023 +0300

    all: imp code, add tests

commit 550f1ab
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 7 19:42:20 2023 +0300

    all: imp docs

commit 6698663
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Apr 7 19:28:54 2023 +0300

    all: introduce bootstrap pkg

internal/bootstrap/bootstrap.go

@@ -23,8 +23,6 @@ type DialHandler func(ctx context.Context, network, addr string) (conn net.Conn,
 
 // ResolveDialContext returns a DialHandler that uses addresses resolved from
 // u using resolvers.  u must not be nil.
-//
-// TODO(e.burkov):  Use in the [upstream] package.
 func ResolveDialContext(
 	u *url.URL,
 	timeout time.Duration,
@@ -68,9 +66,7 @@ func ResolveDialContext(
 }
 
 // NewDialContext returns a DialHandler that dials addrs and returns the first
-// successful connection.
-//
-// TODO(e.burkov):  Use in the [upstream] package.
+// successful connection.  At least a single addr should be specified.
 func NewDialContext(timeout time.Duration, addrs ...string) (h DialHandler) {
 	dialer := &net.Dialer{
 		Timeout: timeout,
@@ -80,7 +76,7 @@ func NewDialContext(timeout time.Duration, addrs ...string) (h DialHandler) {
 	if l == 0 {
 		log.Debug("bootstrap: no addresses to dial")
 
-		return func(ctx context.Context, _, _ string) (conn net.Conn, err error) {
+		return func(_ context.Context, _, _ string) (conn net.Conn, err error) {
 			return nil, errors.Error("no addresses")
 		}
 	}

internal/bootstrap/resolver.go

@@ -48,7 +48,7 @@ func LookupParallel(
 	}
 
 	var errs []error
-	for n := 0; n < resolversNum; n++ {
+	for range resolvers {
 		result := <-ch
 		if result.err == nil {
 			return result.addrs, nil

proxy/lookup_test.go

@@ -14,11 +14,12 @@ func TestLookupIPAddr(t *testing.T) {
 	p := Proxy{}
 	upstreams := make([]upstream.Upstream, 0)
 	// Use AdGuard DNS here
-	opts := &upstream.Options{Timeout: defaultTimeout}
-	dnsUpstream, err := upstream.AddressToUpstream("94.140.14.14", opts)
-	if err != nil {
-		t.Fatalf("cannot prepare the upstream: %s", err)
-	}
+
+	dnsUpstream, err := upstream.AddressToUpstream("94.140.14.14", &upstream.Options{
+		Timeout: defaultTimeout,
+	})
+	require.NoError(t, err)
+
 	p.UpstreamConfig = &UpstreamConfig{}
 	p.UpstreamConfig.Upstreams = append(upstreams, dnsUpstream)
 
@@ -28,22 +29,13 @@ func TestLookupIPAddr(t *testing.T) {
 
 	// Now let's try doing some lookups
 	addrs, err := p.LookupIPAddr("dns.google")
-	assert.Nil(t, err)
-	assert.True(t, len(addrs) == 2 || len(addrs) == 4)
-	assertContainsIP(t, addrs, "8.8.8.8")
-	assertContainsIP(t, addrs, "8.8.4.4")
-	if len(addrs) == 4 {
-		assertContainsIP(t, addrs, "2001:4860:4860::8888")
-		assertContainsIP(t, addrs, "2001:4860:4860::8844")
-	}
-}
+	require.NoError(t, err)
+	require.NotEmpty(t, addrs)
 
-func assertContainsIP(t *testing.T, addrs []net.IPAddr, ip string) {
-	for _, addr := range addrs {
-		if addr.String() == ip {
-			return
-		}
+	assert.Contains(t, addrs, net.IPAddr{IP: net.IP{8, 8, 8, 8}})
+	assert.Contains(t, addrs, net.IPAddr{IP: net.IP{8, 8, 4, 4}})
+	if len(addrs) > 2 {
+		assert.Contains(t, addrs, net.IPAddr{IP: net.ParseIP("2001:4860:4860::8888")})
+		assert.Contains(t, addrs, net.IPAddr{IP: net.ParseIP("2001:4860:4860::8844")})
 	}
-
-	t.Fatalf("%s not found in %v", ip, addrs)
 }