update transport Command interface to support SetAuth after creation

options.go

@@ -22,7 +22,7 @@ var (
 type CloneOptions struct {
 	// The (possibly remote) repository URL to clone from
 	URL string
-	// Auth credentials, if required, to uses with the remote repository
+	// Auth credentials, if required, to use with the remote repository
 	Auth transport.AuthMethod
 	// Name of the remote to be added, by default `origin`
 	RemoteName string
@@ -61,6 +61,8 @@ type PullOptions struct {
 	SingleBranch bool
 	// Limit fetching to the specified number of commits.
 	Depth int
+	// Auth credentials, if required, to use with the remote repository
+	Auth transport.AuthMethod
 }
 
 // Validate validate the fields and set the default values.
@@ -84,6 +86,8 @@ type FetchOptions struct {
 	// Depth limit fetching to the specified number of commits from the tip of
 	// each remote branch history.
 	Depth int
+	// Auth credentials, if required, to use with the remote repository
+	Auth transport.AuthMethod
 }
 
 // Validate validate the fields and set the default values

plumbing/transport/common.go

@@ -30,6 +30,7 @@ var (
 	ErrAuthorizationRequired  = errors.New("authorization required")
 	ErrEmptyUploadPackRequest = errors.New("empty git-upload-pack given")
 	ErrInvalidAuthMethod      = errors.New("invalid auth method")
+	ErrAlreadyConnected       = errors.New("session already established")
 )
 
 const (

plumbing/transport/file/client.go

@@ -35,6 +35,11 @@ func (r *runner) Command(cmd string, ep transport.Endpoint) (common.Command, err
 	case transport.ReceivePackServiceName:
 		cmd = r.ReceivePackBin
 	}
+
+	if _, err := exec.LookPath(cmd); err != nil {
+		return nil, err
+	}
+
 	return &command{cmd: exec.Command(cmd, ep.Path)}, nil
 }
 
@@ -51,6 +56,11 @@ func (c *command) SetAuth(auth transport.AuthMethod) error {
 	return nil
 }
 
+func (c *command) Connect() error {
+	// the file transport requires no network connectivity
+	return nil
+}
+
 func (c *command) Start() error {
 	return c.cmd.Start()
 }

plumbing/transport/git/common.go

@@ -1,7 +1,6 @@
 package git
 
 import (
-	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -13,23 +12,14 @@ import (
 	"gopkg.in/src-d/go-git.v4/utils/ioutil"
 )
 
-var (
-	errAlreadyConnected = errors.New("tcp connection already connected")
-)
-
 // DefaultClient is the default git client.
 var DefaultClient = common.NewClient(&runner{})
 
 type runner struct{}
 
 // Command returns a new Command for the given cmd in the given Endpoint
 func (r *runner) Command(cmd string, ep transport.Endpoint) (common.Command, error) {
-	c := &command{command: cmd, endpoint: ep}
-	if err := c.connect(); err != nil {
-		return nil, err
-	}
-
-	return c, nil
+	return &command{command: cmd, endpoint: ep}, nil
 }
 
 type command struct {
@@ -52,9 +42,9 @@ func (c *command) Start() error {
 	return e.Encode([]byte(cmd))
 }
 
-func (c *command) connect() error {
+func (c *command) Connect() error {
 	if c.connected {
-		return errAlreadyConnected
+		return transport.ErrAlreadyConnected
 	}
 
 	var err error

plumbing/transport/internal/common/common.go

@@ -46,6 +46,8 @@ type Commander interface {
 type Command interface {
 	// SetAuth sets the authentication method.
 	SetAuth(transport.AuthMethod) error
+	// Perform the actual network connection.
+	Connect() error
 	// StderrPipe returns a pipe that will be connected to the command's
 	// standard error when the command starts. It should not be called after
 	// Start.
@@ -100,6 +102,7 @@ type session struct {
 	Stdout  io.Reader
 	Command Command
 
+	connected     bool
 	isReceivePack bool
 	advRefs       *packp.AdvRefs
 	packRun       bool
@@ -113,35 +116,13 @@ func (c *client) newSession(s string, ep transport.Endpoint) (*session, error) {
 		return nil, err
 	}
 
-	stdin, err := cmd.StdinPipe()
-	if err != nil {
-		return nil, err
-	}
-
-	stdout, err := cmd.StdoutPipe()
-	if err != nil {
-		return nil, err
-	}
-
-	stderr, err := cmd.StderrPipe()
-	if err != nil {
-		return nil, err
-	}
-
-	if err := cmd.Start(); err != nil {
-		return nil, err
-	}
-
 	return &session{
-		Stdin:         stdin,
-		Stdout:        stdout,
 		Command:       cmd,
-		errLines:      c.listenErrors(stderr),
 		isReceivePack: s == transport.ReceivePackServiceName,
 	}, nil
 }
 
-func (c *client) listenErrors(r io.Reader) chan string {
+func (s *session) listenErrors(r io.Reader) chan string {
 	if r == nil {
 		return nil
 	}
@@ -158,13 +139,55 @@ func (c *client) listenErrors(r io.Reader) chan string {
 	return errLines
 }
 
+func (s *session) connect() error {
+	if s.connected {
+		return nil
+	}
+
+	err := s.Command.Connect()
+	if err != nil {
+		return err
+	}
+
+	stdin, err := s.Command.StdinPipe()
+	if err != nil {
+		return err
+	}
+
+	stdout, err := s.Command.StdoutPipe()
+	if err != nil {
+		return err
+	}
+
+	stderr, err := s.Command.StderrPipe()
+	if err != nil {
+		return err
+	}
+
+	if err := s.Command.Start(); err != nil {
+		return err
+	}
+
+	s.Stdin = stdin
+	s.Stdout = stdout
+	s.errLines = s.listenErrors(stderr)
+	s.connected = true
+
+	return nil
+}
+
 // SetAuth delegates to the command's SetAuth.
 func (s *session) SetAuth(auth transport.AuthMethod) error {
 	return s.Command.SetAuth(auth)
 }
 
 // AdvertisedReferences retrieves the advertised references from the server.
 func (s *session) AdvertisedReferences() (*packp.AdvRefs, error) {
+	// connect to the remote, allow ErrAlreadyConnected as we might re-use connections
+	if err := s.connect(); err != nil {
+		return nil, err
+	}
+
 	if s.advRefs != nil {
 		return s.advRefs, nil
 	}
@@ -222,6 +245,11 @@ func (s *session) handleAdvRefDecodeError(err error) error {
 // UploadPack performs a request to the server to fetch a packfile. A reader is
 // returned with the packfile content. The reader must be closed after reading.
 func (s *session) UploadPack(req *packp.UploadPackRequest) (*packp.UploadPackResponse, error) {
+	// connect to the remote, allow ErrAlreadyConnected as we might re-use connections
+	if err := s.connect(); err != nil {
+		return nil, err
+	}
+
 	if req.IsEmpty() {
 		return nil, transport.ErrEmptyUploadPackRequest
 	}
@@ -260,6 +288,11 @@ func (s *session) UploadPack(req *packp.UploadPackRequest) (*packp.UploadPackRes
 }
 
 func (s *session) ReceivePack(req *packp.ReferenceUpdateRequest) (*packp.ReportStatus, error) {
+	// connect to the remote, allow ErrAlreadyConnected as we might re-use connections
+	if err := s.connect(); err != nil {
+		return nil, err
+	}
+
 	if _, err := s.AdvertisedReferences(); err != nil {
 		return nil, err
 	}
@@ -307,6 +340,10 @@ func (s *session) finish() error {
 }
 
 func (s *session) Close() error {
+	if !s.connected {
+		return nil
+	}
+
 	if err := s.finish(); err != nil {
 		_ = s.Command.Close()
 		return nil

plumbing/transport/ssh/common.go

@@ -1,7 +1,6 @@
 package ssh
 
 import (
-	"errors"
 	"fmt"
 	"strings"
 
@@ -11,22 +10,13 @@ import (
 	"golang.org/x/crypto/ssh"
 )
 
-var (
-	errAlreadyConnected = errors.New("ssh session already created")
-)
-
 // DefaultClient is the default SSH client.
 var DefaultClient = common.NewClient(&runner{})
 
 type runner struct{}
 
 func (r *runner) Command(cmd string, ep transport.Endpoint) (common.Command, error) {
-	c := &command{command: cmd, endpoint: ep}
-	if err := c.connect(); err != nil {
-		return nil, err
-	}
-
-	return c, nil
+	return &command{command: cmd, endpoint: ep}, nil
 }
 
 type command struct {
@@ -71,13 +61,15 @@ func (c *command) Close() error {
 // SetAuth method, by default uses an auth method based on PublicKeysCallback,
 // it connects to a SSH agent, using the address stored in the SSH_AUTH_SOCK
 // environment var.
-func (c *command) connect() error {
+func (c *command) Connect() error {
 	if c.connected {
-		return errAlreadyConnected
+		return transport.ErrAlreadyConnected
 	}
 
-	if err := c.setAuthFromEndpoint(); err != nil {
-		return err
+	if c.auth == nil {
+		if err := c.setAuthFromEndpoint(); err != nil {
+			return err
+		}
 	}
 
 	var err error

remote.go

@@ -137,6 +137,10 @@ func (r *Remote) fetch(o *FetchOptions) (refs storer.ReferenceStorer, err error)
 		return nil, err
 	}
 
+	if o.Auth != nil {
+		s.SetAuth(o.Auth)
+	}
+
 	defer ioutil.CheckClose(s, &err)
 
 	ar, err := s.AdvertisedReferences()

repository.go

@@ -168,6 +168,7 @@ func (r *Repository) Clone(o *CloneOptions) error {
 	remoteRefs, err := remote.fetch(&FetchOptions{
 		RefSpecs: r.cloneRefSpec(o, c),
 		Depth:    o.Depth,
+		Auth:     o.Auth,
 	})
 	if err != nil {
 		return err
@@ -321,6 +322,7 @@ func (r *Repository) Pull(o *PullOptions) error {
 
 	remoteRefs, err := remote.fetch(&FetchOptions{
 		Depth: o.Depth,
+		Auth:  o.Auth,
 	})
 	if err != nil {
 		return err