[WIP] Add set_memory_request_to_limit option (#406)

* Add set_memory_request_to_limit option

pkg/util/config/config.go

@@ -104,6 +104,7 @@ type Config struct {
 	PodTerminateGracePeriod  time.Duration     `name:"pod_terminate_grace_period" default:"5m"`
 	ProtectedRoles           []string          `name:"protected_role_names" default:"admin"`
 	PostgresSuperuserTeams   []string          `name:"postgres_superuser_teams" default:""`
+	SetMemoryRequestToLimit  bool              `name:"set_memory_request_to_limit" defaults:"false"`
 }
 
 // MustMarshal marshals the config or panics

pkg/util/util.go

@@ -3,12 +3,14 @@ package util
 import (
 	"crypto/md5" // #nosec we need it to for PostgreSQL md5 passwords
 	"encoding/hex"
+	"fmt"
 	"math/rand"
 	"regexp"
 	"strings"
 	"time"
 
 	"github.com/motomux/pretty"
+	resource "k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	"github.com/zalando-incubator/postgres-operator/pkg/spec"
@@ -127,3 +129,19 @@ func Coalesce(val, defaultVal string) string {
 	}
 	return val
 }
+
+// RequestIsSmallerThanLimit
+func RequestIsSmallerThanLimit(requestStr, limitStr string) (bool, error) {
+
+	request, err := resource.ParseQuantity(requestStr)
+	if err != nil {
+		return false, fmt.Errorf("could not parse memory request %v : %v", requestStr, err)
+	}
+
+	limit, err2 := resource.ParseQuantity(limitStr)
+	if err2 != nil {
+		return false, fmt.Errorf("could not parse memory limit %v : %v", limitStr, err2)
+	}
+
+	return request.Cmp(limit) == -1, nil
+}

pkg/util/util_test.go

@@ -69,6 +69,17 @@ var substringMatch = []struct {
 	{regexp.MustCompile(`aaaa (\d+) bbbb`), "aaaa 123 bbbb", nil},
 }
 
+var requestIsSmallerThanLimitTests = []struct {
+	request string
+	limit   string
+	out     bool
+}{
+	{"1G", "2G", true},
+	{"1G", "1Gi", true}, // G is 1000^3 bytes, Gi is 1024^3 bytes
+	{"1024Mi", "1G", false},
+	{"1e9", "1G", false}, // 1e9 bytes == 1G
+}
+
 func TestRandomPassword(t *testing.T) {
 	const pwdLength = 10
 	pwd := RandomPassword(pwdLength)
@@ -143,3 +154,15 @@ func TestMapContains(t *testing.T) {
 		}
 	}
 }
+
+func TestRequestIsSmallerThanLimit(t *testing.T) {
+	for _, tt := range requestIsSmallerThanLimitTests {
+		res, err := RequestIsSmallerThanLimit(tt.request, tt.limit)
+		if err != nil {
+			t.Errorf("RequestIsSmallerThanLimit returned unexpected error: %#v", err)
+		}
+		if res != tt.out {
+			t.Errorf("RequestIsSmallerThanLimit expected: %#v, got: %#v", tt.out, res)
+		}
+	}
+}