socket: restore deprecated Transport.Dial (for now)

This restores the deprecated Transport.Dial, which were removed in commits:

- 61039d0 (Replace deprecated Transport.Dial with Transport.DialContext)
- fb772cf (Fix problems introduced by 61039d0)

While we should still look at removing these, the moby code currently looks to
be depending on their behavior. Removing them caused CI to fail, which blocked
us from updating to the current version of this package.

With those changes, Windows clients in CI were connecting with the wrong daemon,
causing CI failures:

    Failed
    failed to get info from daemon: Error response from daemon: client version 1.41 is too new. Maximum supported API version is 1.40
    exit status 1
    FAIL	github.com/docker/docker/integration/build	0.219s

More details on moby/moby#41042 and moby/moby#41084

This patch restores the deprecated parts, but keeps the new variants as well,
so that we can perform the migration in Moby when possible (after which they
can be removed again)

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

go.mod

@@ -5,4 +5,5 @@ go 1.13
 require (
 	github.com/Microsoft/go-winio v0.4.14
 	github.com/pkg/errors v0.9.1
+	golang.org/x/net v0.0.0-20210716203947-853a461950ff
 )

go.sum

@@ -1,16 +1,21 @@
 github.com/Microsoft/go-winio v0.4.14 h1:+hMXMk01us9KgxGb7ftKQt2Xpf5hH/yky+TDA+qxleU=
 github.com/Microsoft/go-winio v0.4.14/go.mod h1:qXqCSQ3Xa7+6tgxaGTIe4Kpcdsi+P8jBhyzoq1bpyYA=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/sirupsen/logrus v1.4.1/go.mod h1:ni0Sbl8bgC9z8RoU9G6nDWqqs/fq4eDPysMBDgk/93Q=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/net v0.0.0-20210716203947-853a461950ff h1:j2EK/QoxYNBsXI4R7fQkkRUk8y6wnOBI+6hgPdP/6Ds=
+golang.org/x/net v0.0.0-20210716203947-853a461950ff/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190507160741-ecd444e8653b h1:ag/x1USPSsqHud38I9BAC88qdNLDHHtQ4mlgQIZPPNA=
 golang.org/x/sys v0.0.0-20190507160741-ecd444e8653b/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da h1:b3NXsE2LusjYGGjL5bxEVZZORm/YEFFrWFjR8eFrw/c=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

sockets/proxy.go

@@ -2,8 +2,11 @@ package sockets
 
 import (
 	"net"
+	"net/url"
 	"os"
 	"strings"
+
+	"golang.org/x/net/proxy"
 )
 
 // GetProxyEnv allows access to the uppercase and the lowercase forms of
@@ -17,12 +20,36 @@ func GetProxyEnv(key string) string {
 	return proxyValue
 }
 
-// DialerFromEnvironment was previously used to configure a net.Dialer to route
+// DialerFromEnvironment is used to configure a net.Dialer to route
 // connections through a SOCKS proxy.
+//
 // DEPRECATED: SOCKS proxies are now supported by configuring only
 // http.Transport.Proxy, and no longer require changing http.Transport.Dial.
 // Therefore, only sockets.ConfigureTransport() needs to be called, and any
 // sockets.DialerFromEnvironment() calls can be dropped.
-func DialerFromEnvironment(direct *net.Dialer) (*net.Dialer, error) {
-	return direct, nil
+func DialerFromEnvironment(direct *net.Dialer) (proxy.Dialer, error) {
+	allProxy := GetProxyEnv("all_proxy")
+	if len(allProxy) == 0 {
+		return direct, nil
+	}
+
+	proxyURL, err := url.Parse(allProxy)
+	if err != nil {
+		return direct, err
+	}
+
+	proxyFromURL, err := proxy.FromURL(proxyURL, direct)
+	if err != nil {
+		return direct, err
+	}
+
+	noProxy := GetProxyEnv("no_proxy")
+	if len(noProxy) == 0 {
+		return proxyFromURL, nil
+	}
+
+	perHost := proxy.NewPerHost(proxyFromURL, direct)
+	perHost.AddFromString(noProxy)
+
+	return perHost, nil
 }

sockets/sockets.go

@@ -3,6 +3,7 @@ package sockets
 
 import (
 	"errors"
+	"net"
 	"net/http"
 	"time"
 )
@@ -24,6 +25,13 @@ func ConfigureTransport(tr *http.Transport, proto, addr string) error {
 		return configureNpipeTransport(tr, proto, addr)
 	default:
 		tr.Proxy = http.ProxyFromEnvironment
+		dialer, err := DialerFromEnvironment(&net.Dialer{
+			Timeout: defaultTimeout,
+		})
+		if err != nil {
+			return err
+		}
+		tr.Dial = dialer.Dial //nolint: staticcheck // SA1019: tr.Dial is deprecated: Use DialContext instead
 	}
 	return nil
 }

sockets/sockets_unix.go

@@ -19,6 +19,9 @@ func configureUnixTransport(tr *http.Transport, proto, addr string) error {
 	}
 	// No need for compression in local communications.
 	tr.DisableCompression = true
+	tr.Dial = func(_, _ string) (net.Conn, error) { //nolint: staticcheck // SA1019: tr.Dial is deprecated: Use DialContext instead
+		return net.DialTimeout(proto, addr, defaultTimeout)
+	}
 	dialer := &net.Dialer{
 		Timeout: defaultTimeout,
 	}

sockets/sockets_windows.go

@@ -24,6 +24,9 @@ func configureNpipeTransport(tr *http.Transport, proto, addr string) error {
 		//return winio.DialPipeContext(ctx, addr)
 		return DialPipe(addr, defaultTimeout)
 	}
+	tr.Dial = func(_, _ string) (net.Conn, error) { //nolint: staticcheck // SA1019: tr.Dial is deprecated: Use DialContext instead
+		return DialPipe(addr, defaultTimeout)
+	}
 	return nil
 }