fix(logspout): bump packet size to 1048576

By default, linux's socket receivebuffer is set to 256. The kernel
doubles this value to allow space for bookkeeping overhead when it is
set, therefore our maximum packet size is only 512 bytes. Bumping to a
much larger number will prevent an issue like this happening again.
Using SetWriteBuffer sets the operating system's transmit buffer
associated with this connection, and SetReadBuffer sets the operating
system's receive buffer.

Author: Matthew Fisher

logger/syslog/server.go

@@ -97,8 +97,8 @@ func (s *Server) passToHandlers(m SyslogMessage) {
 }
 
 func (s *Server) receiver(c net.PacketConn) {
-	//q := (chan<- Message)(s.q)
-	buf := make([]byte, 1024)
+	// make packet buffer the same size as logspout
+	buf := make([]byte, 1048576)
 	for {
 		n, _, err := c.ReadFrom(buf)
 		if err != nil {

logspout/logspout.go

@@ -28,7 +28,7 @@ func debug(v ...interface{}) {
 
 func assert(err error, context string) {
 	if err != nil {
-		log.Fatal(context+": ", err)
+		log.Fatalf("%s: %v", context, err)
 	}
 }
 
@@ -65,6 +65,8 @@ func syslogStreamer(target Target, types []string, logstream chan *Log) {
 		tag, pid := getLogName(logline.Name)
 		conn, err := net.Dial("udp", target.Addr)
 		assert(err, "syslog")
+		// bump up the packet size for large log lines
+		assert(conn.SetWriteBuffer(1048576), "syslog")
 		// HACK: Go's syslog package hardcodes the log format, so let's send our own message
 		_, err = fmt.Fprintf(conn,
 			"%s %s[%s]: %s",

tests/apps_test.go

@@ -3,6 +3,7 @@
 package tests
 
 import (
+	"math/rand"
 	"os"
 	"testing"
 
@@ -20,6 +21,15 @@ var (
 	appsDestroyCmd        = "apps:destroy --app={{.AppName}} --confirm={{.AppName}}"
 )
 
+func randomString(n int) string {
+	var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+	b := make([]rune, n)
+	for i := range b {
+		b[i] = letters[rand.Intn(len(letters))]
+	}
+	return string(b)
+}
+
 func TestApps(t *testing.T) {
 	params := appsSetup(t)
 	appsCreateTest(t, params)
@@ -99,6 +109,9 @@ func appsRunTest(t *testing.T, params *utils.DeisTestConfig) {
 	}
 	utils.Execute(t, cmd, params, false, "hello")
 	utils.Execute(t, "apps:run env", params, true, "GIT_SHA")
+	// run a REALLY large command to test https://github.com/deis/deis/issues/2046
+	largeString := randomString(1024)
+	utils.Execute(t, "apps:run echo "+largeString, params, false, largeString)
 	if err := utils.Chdir(".."); err != nil {
 		t.Fatal(err)
 	}