transport/ssh: allow global *ssh.ClientConfig override

A global *ssh.ClientConfig override can be set. It will be
use to override values of each SSH session.

1 files changed, 31 insertions, 14 deletions

diff --git a/plumbing/transport/ssh/common.go b/plumbing/transport/ssh/common.go
index 6ab0835..6d1c51b 100644
--- a/plumbing/transport/ssh/common.go
+++ b/plumbing/transport/ssh/common.go
@@ -3,6 +3,7 @@ package ssh
 
 import (
 	"fmt"
+	"reflect"
 
 	"gopkg.in/src-d/go-git.v4/plumbing/transport"
 	"gopkg.in/src-d/go-git.v4/plumbing/transport/internal/common"
@@ -11,17 +12,13 @@ import (
 )
 
 // DefaultClient is the default SSH client.
-var DefaultClient = NewClient()
+var DefaultClient = NewClient(nil)
 
-// NewClient creates a new SSH client with the given options.
-func NewClient(opts ...ClientOption) transport.Transport {
-	return common.NewClient(&runner{options: opts})
+// NewClient creates a new SSH client with an optional *ssh.ClientConfig.
+func NewClient(config *ssh.ClientConfig) transport.Transport {
+	return common.NewClient(&runner{config: config})
 }
 
-// ClientOption is a function that gets a standard ssh.ClientConfig and modifies
-// it.
-type ClientOption func(config *ssh.ClientConfig)
-
 // DefaultAuthBuilder is the function used to create a default AuthMethod, when
 // the user doesn't provide any.
 var DefaultAuthBuilder = func(user string) (AuthMethod, error) {
@@ -31,11 +28,11 @@ var DefaultAuthBuilder = func(user string) (AuthMethod, error) {
 const DefaultPort = 22
 
 type runner struct {
-	options []ClientOption
+	config *ssh.ClientConfig
 }
 
 func (r *runner) Command(cmd string, ep transport.Endpoint, auth transport.AuthMethod) (common.Command, error) {
-	c := &command{command: cmd, endpoint: ep, options: r.options}
+	c := &command{command: cmd, endpoint: ep, config: r.config}
 	if auth != nil {
 		c.setAuth(auth)
 	}
@@ -53,7 +50,7 @@ type command struct {
 	endpoint  transport.Endpoint
 	client    *ssh.Client
 	auth      AuthMethod
-	options   []ClientOption
+	config    *ssh.ClientConfig
 }
 
 func (c *command) setAuth(auth transport.AuthMethod) error {
@@ -107,9 +104,7 @@ func (c *command) connect() error {
 		return err
 	}
 
-	for _, opt := range c.options {
-		opt(config)
-	}
+	overrideConfig(c.config, config)
 
 	c.client, err = ssh.Dial("tcp", c.getHostWithPort(), config)
 	if err != nil {
@@ -145,3 +140,25 @@ func (c *command) setAuthFromEndpoint() error {
 func endpointToCommand(cmd string, ep transport.Endpoint) string {
 	return fmt.Sprintf("%s '%s'", cmd, ep.Path())
 }
+
+func overrideConfig(overrides *ssh.ClientConfig, c *ssh.ClientConfig) {
+	if overrides == nil {
+		return
+	}
+
+	vo := reflect.ValueOf(*overrides)
+	vc := reflect.ValueOf(*c)
+	for i := 0; i < vc.Type().NumField(); i++ {
+		vcf := vc.Field(i)
+		vof := vo.Field(i)
+		if isZeroValue(vcf) {
+			vcf.Set(vof)
+		}
+	}
+
+	*c = vc.Interface().(ssh.ClientConfig)
+}
+
+func isZeroValue(v reflect.Value) bool {
+	return reflect.DeepEqual(v.Interface(), reflect.Zero(v.Type()).Interface())
+}