(fix) reuse ssh client (#17)

* (fix) reuse ssh client
donot create multiple clients if client already exists
this is to not kill the remote server with a lot of ssh open agents

* (feat) auto recover a client

* (feat) minor UI improvement

frontend/src/components/partials/viewer/Inputs.astro

@@ -14,7 +14,7 @@
         type="text"
         x-model="input.query"
         @keyup="submit"
-        class="block font-mono w-full p-3 ps-32 text-sm text-slate-300 hover:text-slate-200 border border-gray-600 hover:border-green-500 focus:border-green-500 rounded-lg bg-gray-900 focus:outline-none"
+        class="block font-mono w-full p-3 ps-32 text-sm text-slate-300 hover:text-slate-200 border-2 border-gray-600 hover:border-green-700 focus:border-green-500 rounded-lg bg-gray-900 focus:outline-none"
         placeholder=".*"
       />
       <span
@@ -45,7 +45,7 @@
         type="text"
         x-model="input.ignore"
         @keyup="submit"
-        class="block font-mono w-full p-3 ps-32 text-sm text-slate-300 hover:text-slate-100 border border-gray-600 hover:border-rose-500 focus:border-rose-500 rounded-lg bg-gray-900 focus:outline-none"
+        class="block font-mono w-full p-3 ps-32 text-sm text-slate-300 hover:text-slate-100 border-2 border-gray-600 hover:border-rose-700 focus:border-rose-500 rounded-lg bg-gray-900 focus:outline-none"
         placeholder=""
       />
     </div>

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/gookit/color v1.5.4
 	github.com/gravwell/gravwell/v3 v3.8.32
 	github.com/k0kubun/pp v3.0.1+incompatible
+	github.com/k0kubun/pp/v3 v3.2.0
 	github.com/kevincobain2000/go-human-uuid v0.0.0-20240321072653-0174cf7003de
 	github.com/labstack/echo/v4 v4.12.0
 	github.com/mcuadros/go-defaults v1.2.0

go.sum

@@ -97,6 +97,8 @@ github.com/k0kubun/colorstring v0.0.0-20150214042306-9440f1994b88 h1:uC1QfSlInpQ
 github.com/k0kubun/colorstring v0.0.0-20150214042306-9440f1994b88/go.mod h1:3w7q1U84EfirKl04SVQ/s7nPm1ZPhiXd34z40TNz36k=
 github.com/k0kubun/pp v3.0.1+incompatible h1:3tqvf7QgUnZ5tXO6pNAZlrvHgl6DvifjDrd9g2S9Z40=
 github.com/k0kubun/pp v3.0.1+incompatible/go.mod h1:GWse8YhT0p8pT4ir3ZgBbfZild3tgzSScAn6HmfYukg=
+github.com/k0kubun/pp/v3 v3.2.0 h1:h33hNTZ9nVFNP3u2Fsgz8JXiF5JINoZfFq4SvKJwNcs=
+github.com/k0kubun/pp/v3 v3.2.0/go.mod h1:ODtJQbQcIRfAD3N+theGCV1m/CBxweERz2dapdz1EwA=
 github.com/kevincobain2000/go-human-uuid v0.0.0-20240321072653-0174cf7003de h1:KZUjqJeNpkuyfo8g5g/5DuaMtA0NRf0uDUg1cb+TyWQ=
 github.com/kevincobain2000/go-human-uuid v0.0.0-20240321072653-0174cf7003de/go.mod h1:pwoguytL8YNxXpKQRE7XrnAstOJlDf7WFO8EUEAYtLI=
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=

pkg/api_handler.go

@@ -20,10 +20,6 @@ type FileInfo struct {
 	Host       string `json:"host"`
 }
 
-var GlobalFilePaths []FileInfo
-var GlobalPipeTmpFilePath string
-var GlobalPathSSHConfig []SSHPathConfig
-
 func NewAPIHandler() *APIHandler {
 	return &APIHandler{
 		API: NewAPI(),

pkg/files.go

@@ -166,6 +166,7 @@ func GetFileInfos(pattern string, limit int, isRemote bool, sshConfig *SSHConfig
 		color.Warn.Printf("limiting to %d files\n", limit)
 		filePaths = filePaths[:limit]
 	}
+
 	for _, filePath := range filePaths {
 		isText, err := IsReadableFile(filePath, isRemote, sshConfig, false)
 		if err != nil {
@@ -317,11 +318,7 @@ func sshConnect(config *SSHConfig) (*ssh.Client, error) {
 }
 
 func sshOpenFile(filename string, config *SSHConfig) (*os.File, error) {
-	client, err := sshConnect(config)
-	if err != nil {
-		return nil, err
-	}
-	session, err := client.NewSession()
+	session, err := NewSession(config)
 	if err != nil {
 		return nil, err
 	}
@@ -336,7 +333,9 @@ func sshOpenFile(filename string, config *SSHConfig) (*os.File, error) {
 	var stdout bytes.Buffer
 	session.Stdout = &stdout
 	if err := session.Run("cat " + filename); err != nil {
-		return nil, err
+		if err.Error() != ErrorMsgSessionAlreadyStarted {
+			return nil, err
+		}
 	}
 
 	// Write the remote file content to the temporary file
@@ -353,11 +352,8 @@ func sshOpenFile(filename string, config *SSHConfig) (*os.File, error) {
 }
 
 func sshFilesByPattern(pattern string, config *SSHConfig) ([]string, error) {
-	client, err := sshConnect(config)
-	if err != nil {
-		return nil, err
-	}
-	session, err := client.NewSession()
+	session, err := NewSession(config)
+
 	if err != nil {
 		return nil, err
 	}
@@ -368,7 +364,9 @@ func sshFilesByPattern(pattern string, config *SSHConfig) ([]string, error) {
 
 	// Execute the ls command to list files matching the pattern
 	if err := session.Run("ls " + pattern); err != nil {
-		return nil, err
+		if err.Error() != ErrorMsgSessionAlreadyStarted {
+			return nil, err
+		}
 	}
 
 	filePaths := buf.String()

pkg/globals.go

@@ -0,0 +1,10 @@
+package pkg
+
+import (
+	"golang.org/x/crypto/ssh"
+)
+
+var GlobalFilePaths []FileInfo
+var GlobalPipeTmpFilePath string
+var GlobalPathSSHConfig []SSHPathConfig
+var GlobalSSHClients = make(map[string]*ssh.Client)

pkg/ssh.go

@@ -0,0 +1,53 @@
+package pkg
+
+import (
+	"sync"
+
+	"golang.org/x/crypto/ssh"
+)
+
+var (
+	clientMutex = &sync.Mutex{}
+)
+
+func NewSession(config *SSHConfig) (*ssh.Session, error) {
+	client, err := NewOrReusableClient(config)
+	if err != nil {
+		return nil, err
+	}
+	session, err := client.NewSession()
+	if err != nil {
+		return nil, err
+	}
+	return session, nil
+}
+
+func NewOrReusableClient(config *SSHConfig) (*ssh.Client, error) {
+	key := config.Host + ":" + config.Port
+
+	clientMutex.Lock()
+	client := GlobalSSHClients[key]
+	clientMutex.Unlock()
+
+	if client == nil {
+		c, err := sshConnect(config)
+		if err != nil {
+			return nil, err
+		}
+		clientMutex.Lock()
+		GlobalSSHClients[key] = c
+		clientMutex.Unlock()
+		client = c
+	}
+
+	// check if client is still connected
+	_, _, err := client.SendRequest("", true, nil)
+	if err != nil {
+		clientMutex.Lock()
+		delete(GlobalSSHClients, key)
+		clientMutex.Unlock()
+		return NewOrReusableClient(config)
+	}
+
+	return client, nil
+}

pkg/types.go

@@ -7,4 +7,6 @@ const (
 	TypeDocker       = "docker"
 	TmpStdinPath     = "/tmp/GOL-STDIN-"
 	TmpContainerPath = "/tmp/GOL-CONTAINER-"
+
+	ErrorMsgSessionAlreadyStarted = "ssh: session already started"
 )

pkg/watcher.go

@@ -156,26 +156,24 @@ func (w *Watcher) initializeScanner() (*os.File, *bufio.Scanner, error) {
 }
 
 func (w *Watcher) initializeRemoteScanner() (*os.File, *bufio.Scanner, error) {
-	client, err := ssh.Dial("tcp", fmt.Sprintf("%s:%s", w.sshHost, w.sshPort), w.sshConfig)
-	if err != nil {
-		return nil, nil, tracerr.New(err.Error())
+	sshConfig := SSHConfig{
+		Host: w.sshHost,
+		Port: w.sshPort,
 	}
-
-	session, err := client.NewSession()
+	session, err := NewSession(&sshConfig)
 	if err != nil {
 		return nil, nil, tracerr.New(err.Error())
 	}
+	defer session.Close()
 
 	var b bytes.Buffer
 	session.Stdout = &b
-	err = session.Run(fmt.Sprintf("cat %s", w.filePath))
-	if err != nil {
-		return nil, nil, tracerr.New(err.Error())
+	if err := session.Run(fmt.Sprintf("cat %s", w.filePath)); err != nil {
+		if err.Error() != ErrorMsgSessionAlreadyStarted {
+			return nil, nil, tracerr.New(err.Error())
+		}
 	}
 
-	session.Close()
-	client.Close()
-
 	scanner := bufio.NewScanner(strings.NewReader(b.String()))
 
 	return nil, scanner, nil