check .ssh/config for host and port overrides; fixes #629

plumbing/transport/ssh/common.go

@@ -4,16 +4,26 @@ package ssh
 import (
 	"fmt"
 	"reflect"
+	"strconv"
 
 	"gopkg.in/src-d/go-git.v4/plumbing/transport"
 	"gopkg.in/src-d/go-git.v4/plumbing/transport/internal/common"
 
+	"github.com/kevinburke/ssh_config"
 	"golang.org/x/crypto/ssh"
 )
 
 // DefaultClient is the default SSH client.
 var DefaultClient = NewClient(nil)
 
+// DefaultSSHConfig is the reader used to access parameters stored in the
+// system's ssh_config files. If nil all the ssh_config are ignored.
+var DefaultSSHConfig sshConfig = ssh_config.DefaultUserSettings
+
+type sshConfig interface {
+	Get(alias, key string) string
+}
+
 // NewClient creates a new SSH client with an optional *ssh.ClientConfig.
 func NewClient(config *ssh.ClientConfig) transport.Transport {
 	return common.NewClient(&runner{config: config})
@@ -121,6 +131,10 @@ func (c *command) connect() error {
 }
 
 func (c *command) getHostWithPort() string {
+	if addr, found := c.doGetHostWithPortFromSSHConfig(); found {
+		return addr
+	}
+
 	host := c.endpoint.Host
 	port := c.endpoint.Port
 	if port <= 0 {
@@ -130,6 +144,35 @@ func (c *command) getHostWithPort() string {
 	return fmt.Sprintf("%s:%d", host, port)
 }
 
+func (c *command) doGetHostWithPortFromSSHConfig() (addr string, found bool) {
+	if DefaultSSHConfig == nil {
+		return
+	}
+
+	host := c.endpoint.Host
+	port := c.endpoint.Port
+
+	configHost := DefaultSSHConfig.Get(c.endpoint.Host, "Hostname")
+	if configHost != "" {
+		host = configHost
+		found = true
+	}
+
+	if !found {
+		return
+	}
+
+	configPort := DefaultSSHConfig.Get(c.endpoint.Host, "Port")
+	if configPort != "" {
+		if i, err := strconv.Atoi(configPort); err == nil {
+			port = i
+		}
+	}
+
+	addr = fmt.Sprintf("%s:%d", host, port)
+	return
+}
+
 func (c *command) setAuthFromEndpoint() error {
 	var err error
 	c.auth, err = DefaultAuthBuilder(c.endpoint.User)

plumbing/transport/ssh/common_test.go

@@ -3,9 +3,12 @@ package ssh
 import (
 	"testing"
 
+	"github.com/kevinburke/ssh_config"
+
 	"golang.org/x/crypto/ssh"
 
 	. "gopkg.in/check.v1"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport"
 )
 
 func Test(t *testing.T) { TestingT(t) }
@@ -39,3 +42,67 @@ func (s *SuiteCommon) TestOverrideConfigKeep(c *C) {
 	overrideConfig(config, target)
 	c.Assert(target.User, Equals, "foo")
 }
+
+func (s *SuiteCommon) TestDefaultSSHConfig(c *C) {
+	defer func() {
+		DefaultSSHConfig = ssh_config.DefaultUserSettings
+	}()
+
+	DefaultSSHConfig = &mockSSHConfig{map[string]map[string]string{
+		"github.com": map[string]string{
+			"Hostname": "foo.local",
+			"Port":     "42",
+		},
+	}}
+
+	ep, err := transport.NewEndpoint("[email protected]:foo/bar.git")
+	c.Assert(err, IsNil)
+
+	cmd := &command{endpoint: ep}
+	c.Assert(cmd.getHostWithPort(), Equals, "foo.local:42")
+}
+
+func (s *SuiteCommon) TestDefaultSSHConfigNil(c *C) {
+	defer func() {
+		DefaultSSHConfig = ssh_config.DefaultUserSettings
+	}()
+
+	DefaultSSHConfig = nil
+
+	ep, err := transport.NewEndpoint("[email protected]:foo/bar.git")
+	c.Assert(err, IsNil)
+
+	cmd := &command{endpoint: ep}
+	c.Assert(cmd.getHostWithPort(), Equals, "github.com:22")
+}
+
+func (s *SuiteCommon) TestDefaultSSHConfigWildcard(c *C) {
+	defer func() {
+		DefaultSSHConfig = ssh_config.DefaultUserSettings
+	}()
+
+	DefaultSSHConfig = &mockSSHConfig{Values: map[string]map[string]string{
+		"*": map[string]string{
+			"Port": "42",
+		},
+	}}
+
+	ep, err := transport.NewEndpoint("[email protected]:foo/bar.git")
+	c.Assert(err, IsNil)
+
+	cmd := &command{endpoint: ep}
+	c.Assert(cmd.getHostWithPort(), Equals, "github.com:22")
+}
+
+type mockSSHConfig struct {
+	Values map[string]map[string]string
+}
+
+func (c *mockSSHConfig) Get(alias, key string) string {
+	a, ok := c.Values[alias]
+	if !ok {
+		return c.Values["*"][key]
+	}
+
+	return a[key]
+}