Fix for issue intelsdi-x#1167, added handling of errors which are ret…

…urned by scanner

control/plugin/execution.go

@@ -115,6 +115,7 @@ func (e *ExecutablePlugin) Run(timeout time.Duration) (Response, error) {
 	e.cmd.Start()
 	e.captureStderr()
 	go func() {
+	OK:
 		for stdOutScanner.Scan() {
 			// The first chunk from the scanner is the plugin's response to the
 			// handshake.  Once we've received that, we can begin to forward
@@ -130,7 +131,28 @@ func (e *ExecutablePlugin) Run(timeout time.Duration) (Response, error) {
 					"io":     "stdout",
 				}).Debug(stdOutScanner.Text())
 			}
+
 		}
+
+		if err := stdOutScanner.Err(); err != nil {
+			if err == bufio.ErrTooLong {
+				reader := bufio.NewReader(e.stdout)
+				log, _, _ := reader.ReadLine()
+
+				execLogger.
+					WithField("plugin", path.Base(e.cmd.Path())).
+					WithField("io", "stdout").
+					WithField("scanner_err", stdOutScanner.Err()).
+					Debug(string(log))
+				goto OK
+			}
+
+			execLogger.
+				WithField("plugin", path.Base(e.cmd.Path())).
+				WithField("io", "stdout").
+				Error(stdOutScanner.Err())
+		}
+
 	}()
 
 	// Wait until:
@@ -167,12 +189,32 @@ func (e *ExecutablePlugin) Kill() error {
 func (e *ExecutablePlugin) captureStderr() {
 	stdErrScanner := bufio.NewScanner(e.stderr)
 	go func() {
+	OK:
 		for stdErrScanner.Scan() {
 			execLogger.
-				WithField("io", "stderr").
 				WithField("plugin", path.Base(e.cmd.Path())).
+				WithField("io", "stderr").
 				Debug(stdErrScanner.Text())
 
 		}
+
+		if err := stdErrScanner.Err(); err != nil {
+			if err == bufio.ErrTooLong {
+				reader := bufio.NewReader(e.stderr)
+				log, _, _ := reader.ReadLine()
+
+				execLogger.
+					WithField("plugin", path.Base(e.cmd.Path())).
+					WithField("io", "stderr").
+					WithField("scanner_err", stdErrScanner.Err()).
+					Debug(string(log))
+				goto OK
+			}
+
+			execLogger.
+				WithField("plugin", path.Base(e.cmd.Path())).
+				WithField("io", "stderr").
+				Error(stdErrScanner.Err())
+		}
 	}()
 }

plugin/collector/snap-plugin-collector-mock2/mock/mock.go

@@ -20,9 +20,11 @@ limitations under the License.
 package mock
 
 import (
+	"bufio"
 	"fmt"
 	"log"
 	"math/rand"
+	"os"
 	"time"
 
 	"github.com/intelsdi-x/snap/control/plugin"
@@ -56,14 +58,24 @@ func (f *Mock) CollectMetrics(mts []plugin.MetricType) ([]plugin.MetricType, err
 	rand.Seed(time.Now().UTC().UnixNano())
 	metrics := []plugin.MetricType{}
 	for i := range mts {
-		if c, ok := mts[i].Config().Table()["long_print"]; ok && c.(ctypes.ConfigValueBool).Value {
+		if c, ok := mts[i].Config().Table()["long_stdout_log"]; ok && c.(ctypes.ConfigValueBool).Value {
 			letterBytes := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
 			longLine := []byte{}
-			for i := 0; i < 8193; i++ {
+			for i := 0; i < bufio.MaxScanTokenSize; i++ {
 				longLine = append(longLine, letterBytes[rand.Intn(len(letterBytes))])
 			}
-			fmt.Println(string(longLine))
+			fmt.Fprintln(os.Stdout, string(longLine))
 		}
+
+		if c, ok := mts[i].Config().Table()["long_stderr_log"]; ok && c.(ctypes.ConfigValueBool).Value {
+			letterBytes := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+			longLine := []byte{}
+			for i := 0; i < bufio.MaxScanTokenSize; i++ {
+				longLine = append(longLine, letterBytes[rand.Intn(len(letterBytes))])
+			}
+			fmt.Fprintln(os.Stderr, string(longLine))
+		}
+
 		if c, ok := mts[i].Config().Table()["panic"]; ok && c.(ctypes.ConfigValueBool).Value {
 			panic("Oops!")
 		}