further refactor of building and copying pilosactl

cmd/pilosactl/main.go

@@ -13,7 +13,6 @@ import (
 	"log"
 	"math/rand"
 	"os"
-	"os/exec"
 	"os/signal"
 	"path"
 	"path/filepath"
@@ -1374,10 +1373,6 @@ func (cmd *BspawnCommand) ParseFlags(args []string) error {
 	if err != nil {
 		return err
 	}
-
-	// handle pilosa creation
-	// handle agent creation
-
 	return nil
 }
 
@@ -1432,43 +1427,22 @@ func (cmd *BspawnCommand) Run(ctx context.Context) error {
 	}
 }
 
-func copyBinary(agentConnections []*pilosactl.SSH, pkg, goos, goarch string) error {
-	binName := path.Base(pkg)
-	binLoc := path.Join(os.TempDir(), binName)
-	com := exec.Command("go", "build", "-o", binLoc, pkg)
-	com.Env = append([]string{"GOOS=" + goos, "GOARCH=" + goarch}, os.Environ()...)
-
-	err := com.Run()
+func copyBinary(fleet pilosactl.SSHFleet, pkg, goos, goarch string) error {
+	bin, err := pilosactl.BuildBinary(pkg, goos, goarch)
 	if err != nil {
 		return err
 	}
 
-	agentWriters := make([]io.Writer, len(agentConnections))
-	for i, conn := range agentConnections {
-		agentWriters[i], err = conn.OpenFile(binName, "+x")
-		if err != nil {
-			return err
-		}
-	}
-
-	f, err := os.Open(binLoc)
-	if err != nil {
-		return err
-	}
-	_, err = io.Copy(io.MultiWriter(agentWriters...), f)
+	wc, err := fleet.OpenFile(path.Base(pkg), "+x")
 	if err != nil {
 		return err
 	}
 
-	for _, w := range agentWriters {
-		if wc, ok := w.(io.WriteCloser); ok {
-			err = wc.Close()
-			if err != nil {
-				return err
-			}
-		}
+	_, err = io.Copy(wc, bin)
+	if err != nil {
+		return err
 	}
-	return nil
+	return wc.Close()
 }
 
 func (cmd *BspawnCommand) spawnRemote(ctx context.Context, runUUID uuid.UUID) error {

pilosactl/build.go

@@ -0,0 +1,29 @@
+package pilosactl
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+)
+
+func BuildBinary(pkg, goos, goarch string) (io.Reader, error) {
+	binFile, err := ioutil.TempFile("", "pilosactl")
+	if err != nil {
+		return nil, fmt.Errorf("build binary: %v", err)
+	}
+	com := exec.Command("go", "build", "-o", binFile.Name(), pkg)
+	com.Env = append([]string{"GOOS=" + goos, "GOARCH=" + goarch}, os.Environ()...)
+
+	err = com.Run()
+	if err != nil {
+		return nil, err
+	}
+
+	f, err := os.Open(binFile.Name())
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}

pilosactl/ssh.go

@@ -8,6 +8,8 @@ import (
 	"os/user"
 	"strings"
 
+	"errors"
+
 	"golang.org/x/crypto/ssh"
 	"golang.org/x/crypto/ssh/agent"
 )
@@ -57,7 +59,9 @@ func NewSSH(host, username, keyfile string, stderr io.Writer) (*SSH, error) {
 	return &SSH{client: client, Stderr: stderr}, nil
 }
 
-func SSHClients(hosts []string, username, keyfile string, stderr io.Writer) ([]*SSH, error) {
+type SSHFleet []*SSH
+
+func SSHClients(hosts []string, username, keyfile string, stderr io.Writer) (SSHFleet, error) {
 	clients := make([]*SSH, len(hosts))
 	for i, host := range hosts {
 		client, err := NewSSH(host, username, keyfile, stderr)
@@ -96,7 +100,7 @@ func (r *remoteFile) Close() error {
 // will be passed directly to chmod to set the file permissions. rm, touch,
 // chmod, cat and support for semicolons, double ampersand, and output
 // redirection (>>) must be available in the remote shell.
-func (s *SSH) OpenFile(name string, perm string) (io.WriteCloser, error) {
+func (s *SSH) OpenFile(name, perm string) (io.WriteCloser, error) {
 	sess, err := s.NewSession()
 	if err != nil {
 		return nil, err
@@ -115,3 +119,51 @@ func (s *SSH) OpenFile(name string, perm string) (io.WriteCloser, error) {
 
 	return &remoteFile{w: w, sess: sess}, nil
 }
+
+type multiWriteCloser struct {
+	wcs []io.WriteCloser
+	ws  []io.Writer
+}
+
+func newMultiWriteCloser() *multiWriteCloser {
+	return &multiWriteCloser{
+		wcs: make([]io.WriteCloser, 0),
+		ws:  make([]io.Writer, 0),
+	}
+}
+
+func (mwc *multiWriteCloser) add(wc io.WriteCloser) {
+	mwc.wcs = append(mwc.wcs, wc)
+	mwc.ws = append(mwc.ws, wc)
+}
+
+func (mwc *multiWriteCloser) Write(p []byte) (n int, err error) {
+	mw := io.MultiWriter(mwc.ws...)
+	return mw.Write(p)
+}
+
+func (mwc *multiWriteCloser) Close() error {
+	errStr := ""
+	for _, wc := range mwc.wcs {
+		err := wc.Close()
+		if err != nil {
+			errStr = errStr + "; " + err.Error()
+		}
+	}
+	if errStr != "" {
+		return errors.New(errStr)
+	}
+	return nil
+}
+
+func (sf SSHFleet) OpenFile(name, perm string) (io.WriteCloser, error) {
+	writers := newMultiWriteCloser()
+	for _, cli := range sf {
+		wc, err := cli.OpenFile(name, "+x")
+		if err != nil {
+			return nil, err
+		}
+		writers.add(wc)
+	}
+	return writers, nil
+}