From 5afe3f7f7ad2942375270267817113ca00f6039a Mon Sep 17 00:00:00 2001
From: talwai <aaditya.21@gmail.com>
Date: Wed, 19 Aug 2015 18:06:20 -0400
Subject: [PATCH 1/2] [filesystem] better signal handling for timeout

---
 filesystem/filesystem.go | 41 ++++++++++++++++++++++------------------
 1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/filesystem/filesystem.go b/filesystem/filesystem.go
index cc05beb..eaeb414 100644
--- a/filesystem/filesystem.go
+++ b/filesystem/filesystem.go
@@ -15,8 +15,8 @@ func getFileSystemInfo() (interface{}, error) {
 	/* Grab filesystem data from df	*/
 	cmd := exec.Command("df", dfOptions...)
 
-	outCh := make(chan []byte)
-	errCh := make(chan error)
+	outCh := make(chan []byte, 1)
+	errCh := make(chan error, 1)
 
 	var out interface{}
 	var err error
@@ -24,28 +24,33 @@ func getFileSystemInfo() (interface{}, error) {
 	go func() {
 		_out, _err := cmd.Output()
 		if _err != nil {
-			errCh <- _err
+			errCh <- fmt.Errorf("df failed to collect filesystem data: %s", _err)
 			return
 		}
 		outCh <- _out
 	}()
 
-	select {
-	case res := <-outCh:
-		if res != nil {
-			out, err = parseDfOutput(string(res))
-		} else {
-			out, err = nil, fmt.Errorf("df process timed out and was killed!")
+WAIT:
+	for {
+		select {
+		case res := <-outCh:
+			if res != nil {
+				out, err = parseDfOutput(string(res))
+			} else {
+				out, err = nil, fmt.Errorf("df failed to collect filesystem data")
+			}
+			break WAIT
+		case err = <-errCh:
+			out = nil
+			break WAIT
+		case <-time.After(2 * time.Second):
+			// Kill the process if it takes too long
+			if killErr := cmd.Process.Kill(); killErr != nil {
+				log.Fatal("failed to kill:", killErr)
+				// Force goroutine to exit
+				<-outCh
+			}
 		}
-	case err = <-errCh:
-		out = nil
-	case <-time.After(5 * time.Second):
-		// Kill the process if it takes too long
-		if killErr := cmd.Process.Kill(); killErr != nil {
-			log.Fatal("failed to kill:", killErr)
-		}
-		//Let goroutine exit
-		<-outCh
 	}
 
 	return out, err

From da80d6ebedd9db40c60765bb7f123af296eea853 Mon Sep 17 00:00:00 2001
From: talwai <aaditya.21@gmail.com>
Date: Fri, 21 Aug 2015 10:48:29 -0400
Subject: [PATCH 2/2] [filesystem] add test for timeout

---
 filesystem/filesystem_test.go | 72 +++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 filesystem/filesystem_test.go

diff --git a/filesystem/filesystem_test.go b/filesystem/filesystem_test.go
new file mode 100644
index 0000000..ea3ba47
--- /dev/null
+++ b/filesystem/filesystem_test.go
@@ -0,0 +1,72 @@
+package filesystem
+
+import (
+	"fmt"
+	"log"
+	"os/exec"
+	"reflect"
+	"testing"
+	"time"
+)
+
+func MockSlowGetFileSystemInfo() (interface{}, error) {
+	/* Run a command that will definitely time out */
+	cmd := exec.Command("sleep", "5")
+
+	outCh := make(chan []byte, 1)
+	errCh := make(chan error, 1)
+
+	var out interface{}
+	var err error
+
+	go func() {
+		_out, _err := cmd.Output()
+		if _err != nil {
+			errCh <- fmt.Errorf("df failed to collect filesystem data: %s", _err)
+			return
+		}
+		outCh <- _out
+	}()
+
+WAIT:
+	for {
+		select {
+		case res := <-outCh:
+			if res != nil {
+				out, err = parseDfOutput(string(res))
+			} else {
+				out, err = nil, fmt.Errorf("df failed to collect filesystem data")
+			}
+			break WAIT
+		case err = <-errCh:
+			out = nil
+			break WAIT
+		case <-time.After(2 * time.Second):
+			// Kill the process if it takes too long
+			if killErr := cmd.Process.Kill(); killErr != nil {
+				log.Fatal("failed to kill:", killErr)
+				// Force goroutine to exit
+				<-outCh
+			}
+		}
+	}
+
+	return out, err
+}
+
+func TestSlowGetFileSystemInfo(t *testing.T) {
+	out, err := MockSlowGetFileSystemInfo()
+	if !reflect.DeepEqual(out, nil) {
+		t.Fatalf("Failed! out should be nil. Instead it's %s", out)
+	}
+	if !reflect.DeepEqual(err, fmt.Errorf("df failed to collect filesystem data: signal: killed")) {
+		t.Fatalf("Failed! Wrong error: %s", err)
+	}
+}
+
+func TestGetFileSystemInfo(t *testing.T) {
+	_, err := getFileSystemInfo()
+	if !reflect.DeepEqual(err, nil) {
+		t.Fatalf("getFileSystemInfo failed: %s", err)
+	}
+}