docs: improve clarity of Usage message in main.go

- Modify the `Usage` message in main.go

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

.hadolint.yaml

@@ -1,2 +0,0 @@
-ignored:
-  - DL3018

DOCS.md

@@ -130,18 +130,19 @@ Example configuration for exporting custom secrets:
   - name: ssh commands
     image: ghcr.io/appleboy/drone-ssh
     environment:
-      commit: ${DRONE_BUILD_NUMBER}
+      # MUST BE in UPPERCASE
+      COMMIT:
+        from_secret: commit
     settings:
       host: foo.com
       username: root
       password: 1234
       port: 22
 +     envs:
-        - aws_access_key_id
+        # can be in lowercase (uppercased in code)
         - commit
       script:
-        - export AWS_ACCESS_KEY_ID=$AWS_ACCESS_KEY_ID
-        - echo $commit
+        - echo $COMMIT
 ```
 
 Example configuration for stoping script after first failure:

docker/Dockerfile

@@ -8,7 +8,11 @@ LABEL maintainer="Bo-Yi Wu <appleboy.tw@gmail.com>" \
   org.label-schema.vendor="Bo-Yi Wu" \
   org.label-schema.schema-version="1.0"
 
-RUN apk add --no-cache ca-certificates && \
+LABEL org.opencontainers.image.source=https://github.com/appleboy/drone-ssh
+LABEL org.opencontainers.image.description="Execute commands on a remote host through SSH"
+LABEL org.opencontainers.image.licenses=MIT
+
+RUN apk add --no-cache ca-certificates=20220614-r4 && \
   rm -rf /var/cache/apk/*
 
 COPY release/${TARGETOS}/${TARGETARCH}/drone-ssh /bin/

go.mod

@@ -3,11 +3,11 @@ module github.com/appleboy/drone-ssh
 go 1.18
 
 require (
-	github.com/appleboy/easyssh-proxy v1.3.9
+	github.com/appleboy/easyssh-proxy v1.3.10
 	github.com/joho/godotenv v1.5.1
-	github.com/stretchr/testify v1.8.1
+	github.com/stretchr/testify v1.8.2
 	github.com/urfave/cli/v2 v2.25.1
-	golang.org/x/crypto v0.7.0
+	golang.org/x/crypto v0.8.0
 )
 
 require (
@@ -18,6 +18,6 @@ require (
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
-	golang.org/x/sys v0.6.0 // indirect
+	golang.org/x/sys v0.7.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,8 +1,7 @@
-github.com/ScaleFT/sshkeys v0.0.0-20200327173127-6142f742bca5/go.mod h1:gxOHeajFfvGQh/fxlC8oOKBe23xnnJTif00IFFbiT+o=
 github.com/ScaleFT/sshkeys v1.2.0 h1:5BRp6rTVIhJzXT3VcUQrKgXR8zWA3sOsNeuyW15WUA8=
 github.com/ScaleFT/sshkeys v1.2.0/go.mod h1:gxOHeajFfvGQh/fxlC8oOKBe23xnnJTif00IFFbiT+o=
-github.com/appleboy/easyssh-proxy v1.3.9 h1:b+sVSTz+cVFvfA23HQywMMpm0s5g3gH7jYdBcQqaCQI=
-github.com/appleboy/easyssh-proxy v1.3.9/go.mod h1:G1eQomBEME7NWKA3hE49s5HsT44S5fn0aBxX7k9Yjug=
+github.com/appleboy/easyssh-proxy v1.3.10 h1:iriF68tlrYoxgWhS7t7Wyr0FA+hJlOem5tMfm+RDlx4=
+github.com/appleboy/easyssh-proxy v1.3.10/go.mod h1:T81pu/Cxx/zf/7YXhFCFiucBa4xeQ81ci5b0PFnMRJc=
 github.com/cpuguy83/go-md2man/v2 v2.0.2 h1:p1EgwI/C7NhT0JmVkwCD2ZBK8j4aeHQX2pMHHBfMQ6w=
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -20,29 +19,25 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
-github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
-github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/urfave/cli/v2 v2.25.1 h1:zw8dSP7ghX0Gmm8vugrs6q9Ku0wzweqPyshy+syu9Gw=
 github.com/urfave/cli/v2 v2.25.1/go.mod h1:GHupkWPMM0M/sj1a2b4wUrWBPzazNrIjouW6fmdJLxc=
 github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 h1:bAn7/zixMGCfxrRTfdpNzjtPYqr8smhKouy9mxVdGPU=
 github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673/go.mod h1:N3UwUGtsrSj3ccvlPHLoLsHnpR27oXr4ZE984MbSER8=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200323165209-0ec3e9974c59/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.0.0-20201208171446-5f87f3452ae9/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
-golang.org/x/crypto v0.7.0 h1:AvwMYaRytfdeVt3u6mLaxYtErKYjxA2OXjJ1HHq6t3A=
-golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU=
+golang.org/x/crypto v0.8.0 h1:pd9TJtTueMTVQXzk8E2XESSMQDj/U7OUu0PqJqPXQjQ=
+golang.org/x/crypto v0.8.0/go.mod h1:mRqEX+O9/h5TFCrQhkgjo2yKi0yYA+9ecGkdQoHrywE=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200219091948-cb0a6d8edb6c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
-golang.org/x/term v0.6.0 h1:clScbb1cHjoCkyRbWwBEUZ5H/tIFu5TAXIqaZD0Gcjw=
+golang.org/x/sys v0.7.0 h1:3jlCCIQZPdOYu1h8BkNvLz8Kgwtae2cagcG/VamtZRU=
+golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.7.0 h1:BEvjmm5fURWqcfbSKTdpkDXYBrUS1c0m8agp14W48vQ=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

main.go

@@ -39,12 +39,12 @@ func main() {
 		&cli.StringFlag{
 			Name:    "ssh-key",
 			Usage:   "private ssh key",
-			EnvVars: []string{"PLUGIN_SSH_KEY", "PLUGIN_KEY", "SSH_KEY", "KEY", "INPUT_KEY"},
+			EnvVars: []string{"PLUGIN_SSH_KEY", "PLUGIN_KEY", "SSH_KEY", "INPUT_KEY"},
 		},
 		&cli.StringFlag{
 			Name:    "ssh-passphrase",
 			Usage:   "The purpose of the passphrase is usually to encrypt the private key.",
-			EnvVars: []string{"PLUGIN_SSH_PASSPHRASE", "PLUGIN_PASSPHRASE", "SSH_PASSPHRASE", "PASSPHRASE", "INPUT_PASSPHRASE"},
+			EnvVars: []string{"PLUGIN_SSH_PASSPHRASE", "PLUGIN_PASSPHRASE", "SSH_PASSPHRASE", "INPUT_PASSPHRASE"},
 		},
 		&cli.StringFlag{
 			Name:    "key-path",
@@ -56,68 +56,68 @@ func main() {
 			Name:    "username",
 			Aliases: []string{"user", "u"},
 			Usage:   "connect as user",
-			EnvVars: []string{"PLUGIN_USERNAME", "PLUGIN_USER", "SSH_USERNAME", "USERNAME", "INPUT_USERNAME"},
+			EnvVars: []string{"PLUGIN_USERNAME", "PLUGIN_USER", "SSH_USERNAME", "INPUT_USERNAME"},
 			Value:   "root",
 		},
 		&cli.StringFlag{
 			Name:    "password",
 			Aliases: []string{"P"},
 			Usage:   "user password",
-			EnvVars: []string{"PLUGIN_PASSWORD", "SSH_PASSWORD", "PASSWORD", "INPUT_PASSWORD"},
+			EnvVars: []string{"PLUGIN_PASSWORD", "SSH_PASSWORD", "INPUT_PASSWORD"},
 		},
 		&cli.StringSliceFlag{
 			Name:    "ciphers",
 			Usage:   "The allowed cipher algorithms. If unspecified then a sensible",
-			EnvVars: []string{"PLUGIN_CIPHERS", "SSH_CIPHERS", "CIPHERS", "INPUT_CIPHERS"},
+			EnvVars: []string{"PLUGIN_CIPHERS", "SSH_CIPHERS", "INPUT_CIPHERS"},
 		},
 		&cli.BoolFlag{
 			Name:    "useInsecureCipher",
 			Usage:   "include more ciphers with use_insecure_cipher",
-			EnvVars: []string{"PLUGIN_USE_INSECURE_CIPHER", "SSH_USE_INSECURE_CIPHER", "USE_INSECURE_CIPHER", "INPUT_USE_INSECURE_CIPHER"},
+			EnvVars: []string{"PLUGIN_USE_INSECURE_CIPHER", "SSH_USE_INSECURE_CIPHER", "INPUT_USE_INSECURE_CIPHER"},
 		},
 		&cli.StringFlag{
 			Name:    "fingerprint",
 			Usage:   "fingerprint SHA256 of the host public key, default is to skip verification",
-			EnvVars: []string{"PLUGIN_FINGERPRINT", "SSH_FINGERPRINT", "FINGERPRINT", "INPUT_FINGERPRINT"},
+			EnvVars: []string{"PLUGIN_FINGERPRINT", "SSH_FINGERPRINT", "INPUT_FINGERPRINT"},
 		},
 		&cli.StringSliceFlag{
 			Name:     "host",
 			Aliases:  []string{"H"},
 			Usage:    "connect to host",
-			EnvVars:  []string{"PLUGIN_HOST", "SSH_HOST", "HOST", "INPUT_HOST"},
+			EnvVars:  []string{"PLUGIN_HOST", "SSH_HOST", "INPUT_HOST"},
 			FilePath: ".host",
 		},
 		&cli.IntFlag{
 			Name:    "port",
 			Aliases: []string{"p"},
 			Usage:   "connect to port",
-			EnvVars: []string{"PLUGIN_PORT", "SSH_PORT", "PORT", "INPUT_PORT"},
+			EnvVars: []string{"PLUGIN_PORT", "SSH_PORT", "INPUT_PORT"},
 			Value:   22,
 		},
 		&cli.BoolFlag{
 			Name:    "sync",
 			Usage:   "sync mode",
-			EnvVars: []string{"PLUGIN_SYNC", "SYNC", "INPUT_SYNC"},
+			EnvVars: []string{"PLUGIN_SYNC", "INPUT_SYNC"},
 		},
 		&cli.DurationFlag{
 			Name:    "timeout",
 			Aliases: []string{"t"},
 			Usage:   "connection timeout",
-			EnvVars: []string{"PLUGIN_TIMEOUT", "SSH_TIMEOUT", "TIMEOUT", "INPUT_TIMEOUT"},
+			EnvVars: []string{"PLUGIN_TIMEOUT", "SSH_TIMEOUT", "INPUT_TIMEOUT"},
 			Value:   30 * time.Second,
 		},
 		&cli.DurationFlag{
 			Name:    "command.timeout",
 			Aliases: []string{"T"},
 			Usage:   "command timeout",
-			EnvVars: []string{"PLUGIN_COMMAND_TIMEOUT", "SSH_COMMAND_TIMEOUT", "COMMAND_TIMEOUT", "INPUT_COMMAND_TIMEOUT"},
+			EnvVars: []string{"PLUGIN_COMMAND_TIMEOUT", "SSH_COMMAND_TIMEOUT", "INPUT_COMMAND_TIMEOUT"},
 			Value:   10 * time.Minute,
 		},
 		&cli.StringSliceFlag{
 			Name:    "script",
 			Aliases: []string{"s"},
 			Usage:   "execute commands",
-			EnvVars: []string{"PLUGIN_SCRIPT", "SSH_SCRIPT", "SCRIPT"},
+			EnvVars: []string{"PLUGIN_SCRIPT", "SSH_SCRIPT"},
 		},
 		&cli.StringFlag{
 			Name:    "script.string",
@@ -127,7 +127,7 @@ func main() {
 		&cli.BoolFlag{
 			Name:    "script.stop",
 			Usage:   "stop script after first failure",
-			EnvVars: []string{"PLUGIN_SCRIPT_STOP", "STOP", "INPUT_SCRIPT_STOP"},
+			EnvVars: []string{"PLUGIN_SCRIPT_STOP", "INPUT_SCRIPT_STOP"},
 		},
 		&cli.StringFlag{
 			Name:    "proxy.ssh-key",
@@ -137,7 +137,7 @@ func main() {
 		&cli.StringFlag{
 			Name:    "proxy.ssh-passphrase",
 			Usage:   "The purpose of the passphrase is usually to encrypt the private key.",
-			EnvVars: []string{"PLUGIN_PROXY_SSH_PASSPHRASE", "PLUGIN_PROXY_PASSPHRASE", "PROXY_SSH_PASSPHRASE", "PROXY_PASSPHRASE", "INPUT_PROXY_PASSPHRASE"},
+			EnvVars: []string{"PLUGIN_PROXY_SSH_PASSPHRASE", "PLUGIN_PROXY_PASSPHRASE", "PROXY_SSH_PASSPHRASE", "INPUT_PROXY_PASSPHRASE"},
 		},
 		&cli.StringFlag{
 			Name:    "proxy.key-path",
@@ -174,17 +174,17 @@ func main() {
 		&cli.StringSliceFlag{
 			Name:    "proxy.ciphers",
 			Usage:   "The allowed cipher algorithms. If unspecified then a sensible",
-			EnvVars: []string{"PLUGIN_PROXY_CIPHERS", "SSH_PROXY_CIPHERS", "PROXY_CIPHERS", "INPUT_PROXY_CIPHERS"},
+			EnvVars: []string{"PLUGIN_PROXY_CIPHERS", "PROXY_SSH_CIPHERS", "INPUT_PROXY_CIPHERS"},
 		},
 		&cli.BoolFlag{
 			Name:    "proxy.useInsecureCipher",
 			Usage:   "include more ciphers with use_insecure_cipher",
-			EnvVars: []string{"PLUGIN_PROXY_USE_INSECURE_CIPHER", "SSH_PROXY_USE_INSECURE_CIPHER", "PROXY_USE_INSECURE_CIPHER", "INPUT_PROXY_USE_INSECURE_CIPHER"},
+			EnvVars: []string{"PLUGIN_PROXY_USE_INSECURE_CIPHER", "PROXY_SSH_USE_INSECURE_CIPHER", "INPUT_PROXY_USE_INSECURE_CIPHER"},
 		},
 		&cli.StringFlag{
 			Name:    "proxy.fingerprint",
 			Usage:   "fingerprint SHA256 of the host public key, default is to skip verification",
-			EnvVars: []string{"PLUGIN_PROXY_FINGERPRINT", "SSH_PROXY_FINGERPRINT", "PROXY_FINGERPRINT", "INPUT_PROXY_FINGERPRINT"},
+			EnvVars: []string{"PLUGIN_PROXY_FINGERPRINT", "PROXY_SSH_FINGERPRINT", "PROXY_FINGERPRINT", "INPUT_PROXY_FINGERPRINT"},
 		},
 		&cli.StringSliceFlag{
 			Name:    "envs",
@@ -194,7 +194,13 @@ func main() {
 		&cli.BoolFlag{
 			Name:    "debug",
 			Usage:   "debug mode",
-			EnvVars: []string{"PLUGIN_DEBUG", "DEBUG", "INPUT_DEBUG"},
+			EnvVars: []string{"PLUGIN_DEBUG", "INPUT_DEBUG"},
+		},
+		&cli.StringFlag{
+			Name:    "envs.format",
+			Usage:   "flexible configuration of environment value transfer",
+			EnvVars: []string{"PLUGIN_ENVS_FORMAT", "INPUT_ENVS_FORMAT"},
+			Value:   envsFormat,
 		},
 	}
 
@@ -241,6 +247,7 @@ func run(c *cli.Context) error {
 	if s := c.String("script.string"); s != "" {
 		scripts = append(scripts, s)
 	}
+
 	plugin := Plugin{
 		Config: Config{
 			Key:               c.String("ssh-key"),
@@ -256,6 +263,7 @@ func run(c *cli.Context) error {
 			Script:            scripts,
 			ScriptStop:        c.Bool("script.stop"),
 			Envs:              c.StringSlice("envs"),
+			EnvsFormat:        c.String("envs.format"),
 			Debug:             c.Bool("debug"),
 			Sync:              c.Bool("sync"),
 			Ciphers:           c.StringSlice("ciphers"),

plugin.go

@@ -17,6 +17,7 @@ var (
 	errMissingHost          = errors.New("Error: missing server host")
 	errMissingPasswordOrKey = errors.New("Error: can't connect without a private SSH key or password")
 	errCommandTimeOut       = errors.New("Error: command timeout")
+	envsFormat              = "export {NAME}={VALUE}"
 )
 
 type (
@@ -40,6 +41,7 @@ type (
 		Sync              bool
 		Ciphers           []string
 		UseInsecureCipher bool
+		EnvsFormat        string
 	}
 
 	// Plugin structure
@@ -65,6 +67,7 @@ func (p Plugin) hostPort(host string) (string, string) {
 }
 
 func (p Plugin) exec(host string, wg *sync.WaitGroup, errChannel chan error) {
+	defer wg.Done()
 	host, port := p.hostPort(host)
 	// Create MakeConfig instance with remote username, server address and path to private key.
 	ssh := &easyssh.MakeConfig{
@@ -102,7 +105,7 @@ func (p Plugin) exec(host string, wg *sync.WaitGroup, errChannel chan error) {
 	for _, key := range p.Config.Envs {
 		key = strings.ToUpper(key)
 		if val, found := os.LookupEnv(key); found {
-			env = append(env, "export "+key+"="+escapeArg(val))
+			env = append(env, p.format(p.Config.EnvsFormat, "{NAME}", key, "{VALUE}", escapeArg(val)))
 		}
 	}
 
@@ -117,38 +120,41 @@ func (p Plugin) exec(host string, wg *sync.WaitGroup, errChannel chan error) {
 	stdoutChan, stderrChan, doneChan, errChan, err := ssh.Stream(strings.Join(p.Config.Script, "\n"), p.Config.CommandTimeout)
 	if err != nil {
 		errChannel <- err
-	} else {
-		// read from the output channel until the done signal is passed
-		isTimeout := true
-	loop:
-		for {
-			select {
-			case isTimeout = <-doneChan:
-				break loop
-			case outline := <-stdoutChan:
-				if outline != "" {
-					p.log(host, "out:", outline)
-				}
-			case errline := <-stderrChan:
-				if errline != "" {
-					p.log(host, "err:", errline)
-				}
-			case err = <-errChan:
+		return
+	}
+	// read from the output channel until the done signal is passed
+	isTimeout := true
+loop:
+	for {
+		select {
+		case isTimeout = <-doneChan:
+			break loop
+		case outline := <-stdoutChan:
+			if outline != "" {
+				p.log(host, "out:", outline)
 			}
-		}
-
-		// get exit code or command error.
-		if err != nil {
-			errChannel <- err
-		}
-
-		// command time out
-		if !isTimeout {
-			errChannel <- errCommandTimeOut
+		case errline := <-stderrChan:
+			if errline != "" {
+				p.log(host, "err:", errline)
+			}
+		case err = <-errChan:
 		}
 	}
 
-	wg.Done()
+	// get exit code or command error.
+	if err != nil {
+		errChannel <- err
+	}
+
+	// command time out
+	if !isTimeout {
+		errChannel <- errCommandTimeOut
+	}
+}
+
+func (p Plugin) format(format string, args ...string) string {
+	r := strings.NewReplacer(args...)
+	return r.Replace(format)
 }
 
 func (p Plugin) log(host string, message ...interface{}) {
@@ -164,6 +170,8 @@ func (p Plugin) log(host string, message ...interface{}) {
 
 // Exec executes the plugin.
 func (p Plugin) Exec() error {
+	p.Config.Host = trimValues(p.Config.Host)
+
 	if len(p.Config.Host) == 0 {
 		return errMissingHost
 	}
@@ -172,14 +180,22 @@ func (p Plugin) Exec() error {
 		return errMissingPasswordOrKey
 	}
 
+	if p.Config.EnvsFormat == "" {
+		p.Config.EnvsFormat = envsFormat
+	}
+
 	wg := sync.WaitGroup{}
 	wg.Add(len(p.Config.Host))
 	errChannel := make(chan error)
 	finished := make(chan struct{})
-	for _, host := range p.Config.Host {
-		if p.Config.Sync {
-			p.exec(host, &wg, errChannel)
-		} else {
+	if p.Config.Sync {
+		go func() {
+			for _, host := range p.Config.Host {
+				p.exec(host, &wg, errChannel)
+			}
+		}()
+	} else {
+		for _, host := range p.Config.Host {
 			go p.exec(host, &wg, errChannel)
 		}
 	}
@@ -230,3 +246,18 @@ func (p Plugin) scriptCommands() []string {
 
 	return commands
 }
+
+func trimValues(keys []string) []string {
+	var newKeys []string
+
+	for _, value := range keys {
+		value = strings.TrimSpace(value)
+		if len(value) == 0 {
+			continue
+		}
+
+		newKeys = append(newKeys, value)
+	}
+
+	return newKeys
+}

plugin_test.go

@@ -440,6 +440,41 @@ func TestFingerprint(t *testing.T) {
 	assert.Equal(t, unindent(expected), unindent(buffer.String()))
 }
 
+func TestScriptStopWithMultipleHostAndSyncMode(t *testing.T) {
+	var (
+		buffer   bytes.Buffer
+		expected = `
+			======CMD======
+			mkdir a/b/c
+			mkdir d/e/f
+			======END======
+			err: mkdir: can't create directory 'a/b/c': No such file or directory
+		`
+	)
+
+	plugin := Plugin{
+		Config: Config{
+			Host:     []string{"", "localhost"},
+			Username: "drone-scp",
+			Port:     22,
+			KeyPath:  "./tests/.ssh/id_rsa",
+			Script: []string{
+				"mkdir a/b/c",
+				"mkdir d/e/f",
+			},
+			CommandTimeout: 10 * time.Second,
+			ScriptStop:     true,
+			Sync:           true,
+		},
+		Writer: &buffer,
+	}
+
+	err := plugin.Exec()
+	assert.NotNil(t, err)
+
+	assert.Equal(t, unindent(expected), unindent(buffer.String()))
+}
+
 func TestScriptStop(t *testing.T) {
 	var (
 		buffer   bytes.Buffer