WIP safer logs

main.go

@@ -1,7 +1,7 @@
 package main
 
 import (
-  "bytes"
+  "bufio"
   "io"
   "net"
   "os"
@@ -21,11 +21,19 @@ import (
 const PARALLELIZE = 16
 const instanceNotFound = Error("instance not found")
 
+var msgOut chan string
+var msgErr chan string
+
 func main() {
   if len(os.Args) < 2 {
     usage()
   }
 
+  msgOut = make(chan string, PARALLELIZE)
+  msgErr = make(chan string, PARALLELIZE)
+  go logger(os.Stdout, msgOut)
+  go logger(os.Stderr, msgErr)
+
   var err error
   switch os.Args[1] {
     case "spawn": 
@@ -37,17 +45,23 @@ func main() {
   }
 
   if err != nil {
-    fmt.Fprintf(os.Stderr, "cmd failed: %v\n", err)
+    msgErr <- fmt.Sprintf("cmd failed: %v\n", err)
     os.Exit(1)
   }
 }
 
+func logger(o *os.File, c chan string) {
+  for m := range c {
+    fmt.Fprint(o, m)
+  }
+}
+
 func usage() {
   var programName = "swtool"
   if len(os.Args) > 0 {
     programName = os.Args[0]
   }
-  fmt.Fprintf(os.Stderr, "Usage: %v (spawn|run|destroy)\n", programName)
+  msgErr <- fmt.Sprintf("Usage: %v (spawn|run|destroy)\n", programName)
   os.Exit(1)
 }
 
@@ -70,6 +84,7 @@ type instanceReceiver interface {
 
 func passInstanceTo(r io.Reader, d instanceReceiver) error {
   com := make(chan error, PARALLELIZE)
+
   count := 0
   failed := 0
 
@@ -87,14 +102,15 @@ func passInstanceTo(r io.Reader, d instanceReceiver) error {
     go func(zone, machine, image, name string) {
       err := d.onInstance(zone, machine, image, name)
       if err != nil {
-        fmt.Fprintf(os.Stderr, "❌ Operation failed for %v (%v, %v, %v): %v\n", name, zone, machine, image, err)
+        msgErr <- fmt.Sprintf("❌ Operation failed for %v (%v, %v, %v): %v\n", name, zone, machine, image, err)
       }
       com <- err
     }(zone, machine, image, name)
+
     count += 1
   }
 
-  fmt.Fprintf(os.Stdout, "ℹ️  Waiting for %v servers\n", count)
+  msgOut <- fmt.Sprintf("ℹ️  Waiting for %v servers\n", count)
   for count > 0 {
     err := <- com
     count -= 1
@@ -170,7 +186,7 @@ func (sp *spawner) onInstance(zone, machine, image, name string) error {
   if err == nil {
     ip := parseIP(targetServer)
     if targetServer.State == instance.ServerStateRunning {
-      fmt.Fprintf(os.Stdout, "🟣 Found %v on zone %v with ip %v\n", targetServer.Name, targetServer.Zone, ip)
+      msgOut <- fmt.Sprintf("🟣 Found %v on zone %v with ip %v\n", targetServer.Name, targetServer.Zone, ip)
       return nil
     }
   } else if err == instanceNotFound {
@@ -207,7 +223,7 @@ func (sp *spawner) onInstance(zone, machine, image, name string) error {
   }
 
   ip := parseIP(targetServer)
-  fmt.Fprintf(os.Stdout, "✅ Started %v on zone %v with ip %v\n", targetServer.Name, targetServer.Zone, ip)
+  msgOut <- fmt.Sprintf("✅ Started %v on zone %v with ip %v\n", targetServer.Name, targetServer.Zone, ip)
   return nil
 }
 
@@ -224,7 +240,7 @@ func (dt *destroyer) onInstance(zone, machine, image, name string) error {
 
   targetServer, err := dt.getInstanceByName(z, name)
   if err == instanceNotFound {
-    fmt.Fprintf(os.Stdout, "🟣 %v is already destroyed\n", name)
+    msgOut <- fmt.Sprintf("🟣 %v is already destroyed\n", name)
     return nil
   } else if err != nil {
     return err
@@ -248,7 +264,7 @@ func (dt *destroyer) onInstance(zone, machine, image, name string) error {
   }
 
   ip := parseIP(targetServer)
-  fmt.Fprintf(os.Stdout, "✅ Destroyed %v on zone %v with ip %v\n", targetServer.Name, targetServer.Zone, ip)
+  msgOut <- fmt.Sprintf("✅ Destroyed %v on zone %v with ip %v\n", targetServer.Name, targetServer.Zone, ip)
   return nil
 }
 
@@ -296,7 +312,7 @@ func (r *runner) connect(zone, name string) (*ssh.Client, error) {
 func (r *runner) send(sshClient *ssh.Client) error {
   // Source script
   if len(os.Args) < 3 {
-    return errors.New("Missing script to run on the command line")
+    return errors.New("missing script to run on the command line")
   }
 
   src, err := os.Open(os.Args[2])
@@ -327,6 +343,16 @@ func (r *runner) send(sshClient *ssh.Client) error {
   return err
 }
 
+func readerToChan(r io.Reader, c chan string) {
+  br := bufio.NewReader(r)
+  for {
+    s, err := br.ReadString('\n')
+    if err != nil {
+      break
+    }
+    c <- s
+  }
+}
 func (r *runner) exec(sshClient *ssh.Client) error {
   // Run the script
 	session, err := sshClient.NewSession()
@@ -335,16 +361,21 @@ func (r *runner) exec(sshClient *ssh.Client) error {
 	}
 	defer session.Close()
 
-	var sshStdout, sshStderr bytes.Buffer
-  session.Stdout = &sshStdout
-  session.Stderr = &sshStderr
+  if os.Getenv("VERBOSE") != "" {
+    readErr, err := session.StderrPipe()
+    if err != nil {
+      return err
+    }
+    readerToChan(readErr, msgErr)
+
+    readOut, err := session.StdoutPipe()
+    if err != nil {
+      return err
+    }
+    readerToChan(readOut, msgOut)
+  }
 
   err = session.Run("/tmp/nuage")
-  if os.Getenv("VERBOSE") != "" {
-    fmt.Fprintf(os.Stdout, "logs\n")
-    io.Copy(os.Stdout, &sshStdout)
-    io.Copy(os.Stderr, &sshStderr)
-  }
   if err != nil {
     return err
   }
@@ -369,7 +400,7 @@ func (r *runner) onInstance(zone, machine, image, name string) error {
     return err
   }
 
-  fmt.Fprintf(os.Stdout, "✅ Successfully ran the script on %v (zone %v)\n", name, zone)
+  msgOut <- fmt.Sprintf("✅ Successfully ran the script on %v (zone %v)\n", name, zone)
   return nil
 }