Adds check for tmp dir and create if missing

also test for function

api/tasks/runner.go

@@ -59,6 +59,13 @@ func (t *task) prepareRun() {
 	}()
 
 	t.log("Preparing: " + strconv.Itoa(t.task.ID))
+	
+	err := checkTmpDir(util.Config.TmpPath)
+	if err != nil {
+		t.log("Creating tmp dir failed: " + err.Error())
+		t.fail()
+		return
+	}
 
 	if err := t.populateDetails(); err != nil {
 		t.log("Error: " + err.Error())
@@ -439,3 +446,15 @@ func (t *task) envVars(home string, pwd string, gitSSHCommand *string) []string
 
 	return env
 }
+
+// checkTmpDir checks to see if the temporary directory exists
+// and if it does not attempts to create it
+func checkTmpDir(path string) error {
+	var err error = nil
+	if _, err := os.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			return os.MkdirAll(path, os.FileMode(int(0640)))
+		}
+	}
+	return err
+}

api/tasks/runner_test.go

@@ -0,0 +1,68 @@
+package tasks
+
+import (
+	"testing"
+	"math/rand"
+	"time"
+	"os"
+	"log"
+)
+
+
+func TestCheckTmpDir(t *testing.T) {
+
+	//It should be able to create a random dir in /tmp
+	dirName := os.TempDir()+ "/" + randString(rand.Intn(10 - 4) + 4)
+	err := checkTmpDir(dirName)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	//checking again for this directory should return no error, as it exists
+	err = checkTmpDir(dirName)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = os.Chmod(dirName,os.FileMode(int(0550)))
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = checkTmpDir(dirName+"/noway")
+	if err == nil {
+		t.Fatal("You should not be able to write in this folder, causing an error")
+	}
+	err = os.Remove(dirName)
+	if err != nil {
+		t.Log(err)
+	}
+
+}
+
+
+//HELPERS
+
+//https://stackoverflow.com/questions/22892120/how-to-generate-a-random-string-of-a-fixed-length-in-golang
+var src = rand.NewSource(time.Now().UnixNano())
+const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+const (
+	letterIdxBits = 6                    // 6 bits to represent a letter index
+	letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
+	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
+)
+func randString(n int) string {
+	b := make([]byte, n)
+	// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
+	for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
+		if remain == 0 {
+			cache, remain = src.Int63(), letterIdxMax
+		}
+		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
+			b[i] = letterBytes[idx]
+			i--
+		}
+		cache >>= letterIdxBits
+		remain--
+	}
+	return string(b)
+}