From be20d29a81e816084d7a8d56687a5023aa181394 Mon Sep 17 00:00:00 2001
From: Philip Meulengracht <philip.meulengracht@canonical.com>
Date: Thu, 24 Feb 2022 14:19:42 +0100
Subject: [PATCH] wrappers: review feedback

add new function []int => string in strutils, use that instead of chained string functions
---
 strutil/strutil.go        | 13 +++++++++++++
 wrappers/services.go      |  2 +-
 wrappers/services_test.go |  4 ++--
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/strutil/strutil.go b/strutil/strutil.go
index 3d21cdf8cbd..b255ea467d9 100644
--- a/strutil/strutil.go
+++ b/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 {
diff --git a/wrappers/services.go b/wrappers/services.go
index 1177abd3ec6..6305e5f1664 100644
--- a/wrappers/services.go
+++ b/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)
 	}
 
diff --git a/wrappers/services_test.go b/wrappers/services_test.go
index 807a0c2f304..6763148990f 100644
--- a/wrappers/services_test.go
+++ b/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))
 }