From f5eeed0bc23a4db12c824021723b823e0c1d9aea Mon Sep 17 00:00:00 2001
From: Kota Kanbe <kotakanbe@gmail.com>
Date: Wed, 14 Sep 2016 09:35:15 +0900
Subject: [PATCH] Show error when no scannable servers are detected.

---
 commands/configtest.go | 5 ++++-
 commands/prepare.go    | 6 ++++--
 commands/scan.go       | 5 ++++-
 scan/serverapi.go      | 6 +++++-
 4 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/commands/configtest.go b/commands/configtest.go
index cdab6142..8c97eae2 100644
--- a/commands/configtest.go
+++ b/commands/configtest.go
@@ -150,7 +150,10 @@ func (p *ConfigtestCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interfa
 	}
 
 	Log.Info("Detecting Server/Contianer OS... ")
-	scan.InitServers(Log)
+	if err := scan.InitServers(Log); err != nil {
+		Log.Errorf("Failed to init servers: %s", err)
+		return subcommands.ExitFailure
+	}
 
 	Log.Info("Checking sudo configuration... ")
 	if err := scan.CheckIfSudoNoPasswd(Log); err != nil {
diff --git a/commands/prepare.go b/commands/prepare.go
index c8a67415..5e24719f 100644
--- a/commands/prepare.go
+++ b/commands/prepare.go
@@ -138,7 +138,10 @@ func (p *PrepareCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{
 	logger := util.NewCustomLogger(c.ServerInfo{})
 
 	logger.Info("Detecting OS... ")
-	scan.InitServers(logger)
+	if err := scan.InitServers(logger); err != nil {
+		logger.Errorf("Failed to init servers: %s", err)
+		return subcommands.ExitFailure
+	}
 
 	logger.Info("Checking sudo configuration... ")
 	if err := scan.CheckIfSudoNoPasswd(logger); err != nil {
@@ -154,6 +157,5 @@ func (p *PrepareCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{
 		return subcommands.ExitFailure
 	}
 
-	logger.Info("Success")
 	return subcommands.ExitSuccess
 }
diff --git a/commands/scan.go b/commands/scan.go
index a7082b53..2daee210 100644
--- a/commands/scan.go
+++ b/commands/scan.go
@@ -368,7 +368,10 @@ func (p *ScanCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{})
 	}
 
 	Log.Info("Detecting Server/Contianer OS... ")
-	scan.InitServers(Log)
+	if err := scan.InitServers(Log); err != nil {
+		Log.Errorf("Failed to init servers: %s", err)
+		return subcommands.ExitFailure
+	}
 
 	Log.Info("Checking sudo configuration... ")
 	if err := scan.CheckIfSudoNoPasswd(Log); err != nil {
diff --git a/scan/serverapi.go b/scan/serverapi.go
index 0bbc1d83..4c892181 100644
--- a/scan/serverapi.go
+++ b/scan/serverapi.go
@@ -170,11 +170,15 @@ func PrintSSHableServerNames() {
 }
 
 // InitServers detect the kind of OS distribution of target servers
-func InitServers(localLogger *logrus.Entry) {
+func InitServers(localLogger *logrus.Entry) error {
 	Log = localLogger
 	servers = detectServerOSes()
+	if len(servers) == 0 {
+		return fmt.Errorf("No scannable servers")
+	}
 	containers := detectContainerOSes()
 	servers = append(servers, containers...)
+	return nil
 }
 
 func detectServerOSes() (sshAbleOses []osTypeInterface) {