fix(input.redis): Discard invalid errorstat lines (#15312)

plugins/inputs/redis/redis.go

@@ -665,11 +665,18 @@ func gatherErrorstatsLine(
 	}
 	tags["err"] = strings.TrimPrefix(name, "errorstat_")
 	kv := strings.Split(line, "=")
-	ival, err := strconv.ParseInt(kv[1], 10, 64)
-	if err == nil {
-		fields := map[string]interface{}{"total": ival}
-		acc.AddFields("redis_errorstat", fields, tags)
+	if len(kv) < 2 {
+		acc.AddError(fmt.Errorf("invalid line for %q: %s", name, line))
+		return
 	}
+	ival, err := strconv.ParseInt(kv[1], 10, 64)
+	if err != nil {
+		acc.AddError(fmt.Errorf("parsing value in line %q failed: %w", line, err))
+		return
+	}
+
+	fields := map[string]interface{}{"total": ival}
+	acc.AddFields("redis_errorstat", fields, tags)
 }
 
 func init() {

plugins/inputs/redis/redis_test.go

@@ -15,8 +15,7 @@ import (
 	"github.com/influxdata/telegraf/testutil"
 )
 
-type testClient struct {
-}
+type testClient struct{}
 
 func (t *testClient) BaseTags() map[string]string {
 	return map[string]string{"host": "redis.net"}
@@ -386,6 +385,24 @@ func TestRedis_ParseIntOnString(t *testing.T) {
 	require.IsType(t, int64(0), clientsInTimeout)
 }
 
+func TestRedis_GatherErrorstatsLine(t *testing.T) {
+	var acc testutil.Accumulator
+	globalTags := map[string]string{}
+
+	gatherErrorstatsLine("FOO", "BAR", &acc, globalTags)
+	require.Len(t, acc.Errors, 1)
+	require.Equal(t, "invalid line for \"FOO\": BAR", acc.Errors[0].Error())
+
+	acc = testutil.Accumulator{}
+	gatherErrorstatsLine("FOO", "BAR=a", &acc, globalTags)
+	require.Len(t, acc.Errors, 1)
+	require.Equal(t, "parsing value in line \"BAR=a\" failed: strconv.ParseInt: parsing \"a\": invalid syntax", acc.Errors[0].Error())
+
+	acc = testutil.Accumulator{}
+	gatherErrorstatsLine("FOO", "BAR=77", &acc, globalTags)
+	require.Empty(t, acc.Errors)
+}
+
 const testOutput = `# Server
 redis_version:6.0.9
 redis_git_sha1:00000000