wrappers: review feedback

add new function []int => string in strutils, use that instead of chained string functions

strutil/strutil.go

@@ -39,6 +39,19 @@ func SizeToStr(size int64) string {
 	panic("SizeToStr got a size bigger than math.MaxInt64")
 }
 
+// SliceToCommaSeparatedString converts an int array to a comma-separated string
+func SliceToCommaSeparatedString(vals []int) string {
+	b := &strings.Builder{}
+	last := len(vals) - 1
+	for i, v := range vals {
+		b.WriteString(strconv.Itoa(v))
+		if i != last {
+			b.WriteRune(',')
+		}
+	}
+	return b.String()
+}
+
 // Quoted formats a slice of strings to a quoted list of
 // comma-separated strings, e.g. `"snap1", "snap2"`
 func Quoted(names []string) string {

wrappers/services.go

@@ -117,7 +117,7 @@ func formatCpuGroupSlice(grp *quota.Group) string {
 			return ""
 		}
 
-		allowedCpusValue := strings.Trim(strings.Join(strings.Fields(fmt.Sprint(grp.CPULimit.AllowedCPUs)), ","), "[]")
+		allowedCpusValue := strutil.SliceToCommaSeparatedString(grp.CPULimit.AllowedCPUs)
 		return fmt.Sprintf("AllowedCPUs=%s\n", allowedCpusValue)
 	}
 

wrappers/services_test.go

@@ -284,7 +284,7 @@ TasksAccounting=true
 TasksMax=%[5]d
 `
 
-	allowedCpusValue := strings.Trim(strings.Join(strings.Fields(fmt.Sprint(resourceLimits.CPU.AllowedCPUs)), ","), "[]")
+	allowedCpusValue := strutil.SliceToCommaSeparatedString(resourceLimits.CPU.AllowedCPUs)
 	sliceContent := fmt.Sprintf(sliceTempl, grp.Name,
 		resourceLimits.CPU.Count*resourceLimits.CPU.Percentage,
 		allowedCpusValue,
@@ -851,7 +851,7 @@ MemoryLimit=%[3]d
 TasksAccounting=true
 `
 
-	allowedCpusValue := strings.Trim(strings.Join(strings.Fields(fmt.Sprint(resourceLimits.CPU.AllowedCPUs)), ","), "[]")
+	allowedCpusValue := strutil.SliceToCommaSeparatedString(resourceLimits.CPU.AllowedCPUs)
 	c.Assert(sliceFile, testutil.FileEquals, fmt.Sprintf(templ, "foogroup", allowedCpusValue, resourceLimits.Memory.Limit))
 	c.Assert(subSliceFile, testutil.FileEquals, fmt.Sprintf(templ, "subgroup", allowedCpusValue, resourceLimits.Memory.Limit))
 }