Merge pull request #3779 from jgold-stripe/unix

Add ability to dial API via unix socket

internal/config/config_type.go

@@ -50,6 +50,11 @@ var configOptions = []ConfigOption{
 		Description:  "the terminal pager program to send standard output to",
 		DefaultValue: "",
 	},
+	{
+		Key:          "http_unix_socket",
+		Description:  "the path to a unix socket through which to make HTTP connection",
+		DefaultValue: "",
+	},
 }
 
 func ConfigOptions() []ConfigOption {
@@ -179,6 +184,15 @@ func NewBlankRoot() *yaml.Node {
 							},
 						},
 					},
+					{
+						HeadComment: "The path to a unix socket through which send HTTP connections. If blank, HTTP traffic will be handled by net/http.DefaultTransport.",
+						Kind:        yaml.ScalarNode,
+						Value:       "http_unix_socket",
+					},
+					{
+						Kind:  yaml.ScalarNode,
+						Value: "",
+					},
 				},
 			},
 		},

internal/config/config_type_test.go

@@ -50,6 +50,8 @@ func Test_defaultConfig(t *testing.T) {
 		# Aliases allow you to create nicknames for gh commands
 		aliases:
 		    co: pr checkout
+		# The path to a unix socket through which send HTTP connections. If blank, HTTP traffic will be handled by net/http.DefaultTransport.
+		http_unix_socket:
 	`)
 	assert.Equal(t, expected, mainBuf.String())
 	assert.Equal(t, "", hostsBuf.String())
@@ -81,6 +83,9 @@ func Test_ValidateValue(t *testing.T) {
 
 	err = ValidateValue("got", "123")
 	assert.NoError(t, err)
+
+	err = ValidateValue("http_unix_socket", "really_anything/is/allowed/and/net.Dial\\(...\\)/will/ultimately/validate")
+	assert.NoError(t, err)
 }
 
 func Test_ValidateKey(t *testing.T) {
@@ -98,4 +103,7 @@ func Test_ValidateKey(t *testing.T) {
 
 	err = ValidateKey("pager")
 	assert.NoError(t, err)
+
+	err = ValidateKey("http_unix_socket")
+	assert.NoError(t, err)
 }

internal/httpunix/transport.go

@@ -0,0 +1,21 @@
+// package httpunix provides an http.RoundTripper which dials a server via a unix socket.
+package httpunix
+
+import (
+	"net"
+	"net/http"
+)
+
+// NewRoundTripper returns an http.RoundTripper which sends requests via a unix
+// socket at socketPath.
+func NewRoundTripper(socketPath string) http.RoundTripper {
+	dial := func(network, addr string) (net.Conn, error) {
+		return net.Dial("unix", socketPath)
+	}
+
+	return &http.Transport{
+		Dial:              dial,
+		DialTLS:           dial,
+		DisableKeepAlives: true,
+	}
+}

pkg/cmd/factory/default.go

@@ -85,7 +85,7 @@ func httpClientFunc(f *cmdutil.Factory, appVersion string) func() (*http.Client,
 		if err != nil {
 			return nil, err
 		}
-		return NewHTTPClient(io, cfg, appVersion, true), nil
+		return NewHTTPClient(io, cfg, appVersion, true)
 	}
 }
 

pkg/cmd/factory/http.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/cli/cli/api"
 	"github.com/cli/cli/internal/ghinstance"
+	"github.com/cli/cli/internal/httpunix"
 	"github.com/cli/cli/pkg/iostreams"
 )
 
@@ -57,8 +58,31 @@ type configGetter interface {
 }
 
 // generic authenticated HTTP client for commands
-func NewHTTPClient(io *iostreams.IOStreams, cfg configGetter, appVersion string, setAccept bool) *http.Client {
+func NewHTTPClient(io *iostreams.IOStreams, cfg configGetter, appVersion string, setAccept bool) (*http.Client, error) {
 	var opts []api.ClientOption
+
+	// We need to check and potentially add the unix socket roundtripper option
+	// before adding any other options, since if we are going to use the unix
+	// socket transport, it needs to form the base of the transport chain
+	// represented by invocations of opts...
+	//
+	// Another approach might be to change the signature of api.NewHTTPClient to
+	// take an explicit base http.RoundTripper as its first parameter (it
+	// currently defaults internally to http.DefaultTransport), or add another
+	// variant like api.NewHTTPClientWithBaseRoundTripper. But, the only caller
+	// which would use that non-default behavior is right here, and it doesn't
+	// seem worth the cognitive overhead everywhere else just to serve this one
+	// use case.
+	unixSocket, err := cfg.Get("", "http_unix_socket")
+	if err != nil {
+		return nil, err
+	}
+	if unixSocket != "" {
+		opts = append(opts, api.ClientOption(func(http.RoundTripper) http.RoundTripper {
+			return httpunix.NewRoundTripper(unixSocket)
+		}))
+	}
+
 	if verbose := os.Getenv("DEBUG"); verbose != "" {
 		logTraffic := strings.Contains(verbose, "api")
 		opts = append(opts, api.VerboseLog(io.ErrOut, logTraffic, io.IsStderrTTY()))
@@ -98,7 +122,7 @@ func NewHTTPClient(io *iostreams.IOStreams, cfg configGetter, appVersion string,
 		)
 	}
 
-	return api.NewHTTPClient(opts...)
+	return api.NewHTTPClient(opts...), nil
 }
 
 func getHost(r *http.Request) string {

pkg/cmd/factory/http_test.go

@@ -135,7 +135,8 @@ func TestNewHTTPClient(t *testing.T) {
 			})
 
 			io, _, _, stderr := iostreams.Test()
-			client := NewHTTPClient(io, tt.args.config, tt.args.appVersion, tt.args.setAccept)
+			client, err := NewHTTPClient(io, tt.args.config, tt.args.appVersion, tt.args.setAccept)
+			require.NoError(t, err)
 
 			req, err := http.NewRequest("GET", ts.URL, nil)
 			req.Host = tt.host

pkg/cmd/root/root.go

@@ -118,6 +118,6 @@ func bareHTTPClient(f *cmdutil.Factory, version string) func() (*http.Client, er
 		if err != nil {
 			return nil, err
 		}
-		return factory.NewHTTPClient(f.IOStreams, cfg, version, false), nil
+		return factory.NewHTTPClient(f.IOStreams, cfg, version, false)
 	}
 }