Add proper support for the shared_buffer configuration parameter (#220)

Author: eberlep

api/v1/postgres_types.go

@@ -9,6 +9,7 @@ package v1
 import (
 	"fmt"
 	"reflect"
+	"strconv"
 
 	"regexp"
 
@@ -17,6 +18,7 @@ import (
 	"inet.af/netaddr"
 	corev1 "k8s.io/api/core/v1"
 	networkingv1 "k8s.io/api/networking/v1"
+	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -50,6 +52,8 @@ const (
 	BackupConfigLabelName string = "postgres.database.fits.cloud/is-backup"
 	// BackupConfigKey defines the key under which the BackupConfig is stored in the data map.
 	BackupConfigKey = "config"
+	// SharedBufferParameterKey defines the key under which the shared buffer size is stored in the parameters map. Defined by the postgres-operator/patroni
+	SharedBufferParameterKey = "shared_buffer"
 )
 
 var (
@@ -401,8 +405,8 @@ func (p *Postgres) ToUnstructuredZalandoPostgresql(z *zalando.Postgresql, c *cor
 
 	z.Spec.NumberOfInstances = p.Spec.NumberOfInstances
 	z.Spec.PostgresqlParam.PgVersion = p.Spec.Version
-	// TODO set shared_buffer from p.Spec.Size.SharedBuffer
-	// z.Spec.PostgresqlParam.Parameters = map[string]string{}
+	z.Spec.PostgresqlParam.Parameters = map[string]string{}
+	setSharedBufferSize(z.Spec.PostgresqlParam.Parameters, p.Spec.Size.SharedBuffer)
 	z.Spec.Resources.ResourceRequests.CPU = p.Spec.Size.CPU
 	z.Spec.Resources.ResourceRequests.Memory = p.Spec.Size.Memory
 	z.Spec.Resources.ResourceLimits.CPU = p.Spec.Size.CPU
@@ -542,3 +546,18 @@ func (p *Postgres) buildSidecars(c *corev1.ConfigMap) []zalando.Sidecar {
 
 	return sidecars
 }
+
+// setSharedBufferSize converts and, if valid, sets the shared_buffer parameter in the given map.
+func setSharedBufferSize(parameters map[string]string, shmSize string) {
+	// First step is to convert the string back to a quantity
+	size, err := resource.ParseQuantity(shmSize)
+	if err == nil {
+		// if successful, get the given shared buffer size in bytes.
+		sizeInBytes, ok := size.AsInt64()
+		if ok && sizeInBytes >= (32*1024*1024) {
+			// if more than 32Mi (our minimum value), convert the value to MB as required by postgres (although the docs are not very specific about that)
+			sizeInMB := sizeInBytes / (1024 * 1024)
+			parameters[SharedBufferParameterKey] = strconv.FormatInt(sizeInMB, 10) + "MB"
+		}
+	}
+}

api/v1/postgres_types_test.go

@@ -0,0 +1,85 @@
+/*
+/ SPDX-FileCopyrightText: 2021 Finanz Informatik Technologie Services GmbHs
+/
+/ SPDX-License-Identifier: AGPL-1.0-only
+*/
+
+package v1
+
+import (
+	"testing"
+)
+
+func Test_setSharedBufferSize(t *testing.T) {
+
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "default",
+			input:    "64Mi",
+			expected: "64MB",
+		},
+		{
+			name:     "min",
+			input:    "32Mi",
+			expected: "32MB",
+		},
+		{
+			name:     "belowMin",
+			input:    "31Mi",
+			expected: "",
+		},
+		{
+			name:     "Gibibytes",
+			input:    "1Gi",
+			expected: "1024MB",
+		},
+		{
+			name:     "Kibibytes",
+			input:    "102400Ki",
+			expected: "100MB",
+		},
+		{
+			name:     "Bytes",
+			input:    "67108864",
+			expected: "64MB",
+		},
+		{
+			name:     "empty",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "empty2",
+			input:    " ",
+			expected: "",
+		},
+		{
+			name:     "invalid",
+			input:    "64MB",
+			expected: "",
+		},
+	}
+	for _, tt := range tests {
+		tt := tt // pin!
+		t.Run(tt.name, func(t *testing.T) {
+			parameters := map[string]string{}
+
+			setSharedBufferSize(parameters, tt.input)
+
+			result, ok := parameters[SharedBufferParameterKey]
+			if ok {
+				if tt.expected != result {
+					t.Errorf("Adapter.ScopedGet() assertion failed: expected %q, got %q\n", tt.expected, result)
+				}
+			} else {
+				if tt.expected != "" {
+					t.Errorf("Conversion failed")
+				}
+			}
+		})
+	}
+}