fix: migrate prune policy options to oneof

internal/config/migrations/001prunepolicy.go

@@ -0,0 +1,41 @@
+package migrations
+
+import v1 "github.com/garethgeorge/backrest/gen/go/v1"
+
+func migration001PrunePolicy(config *v1.Config) {
+	// loop over plans and examine prune policy's
+	for _, plan := range config.Plans {
+		policy := plan.GetRetention()
+		if policy == nil {
+			continue
+		}
+
+		if policy.Policy != nil {
+			continue // already migrated
+		}
+
+		if policy.KeepLastN != 0 {
+			plan.Retention = &v1.RetentionPolicy{
+				Policy: &v1.RetentionPolicy_PolicyKeepLastN{
+					PolicyKeepLastN: policy.KeepLastN,
+				},
+			}
+		} else if policy.KeepDaily != 0 || policy.KeepHourly != 0 || policy.KeepMonthly != 0 || policy.KeepWeekly != 0 || policy.KeepYearly != 0 {
+			plan.Retention = &v1.RetentionPolicy{
+				Policy: &v1.RetentionPolicy_PolicyTimeBucketed{
+					PolicyTimeBucketed: &v1.RetentionPolicy_TimeBucketedCounts{
+						Hourly:  policy.KeepHourly,
+						Daily:   policy.KeepDaily,
+						Weekly:  policy.KeepWeekly,
+						Monthly: policy.KeepMonthly,
+						Yearly:  policy.KeepYearly,
+					},
+				},
+			}
+		} else {
+			policy.Policy = &v1.RetentionPolicy_PolicyKeepAll{
+				PolicyKeepAll: true,
+			}
+		}
+	}
+}

internal/config/migrations/001prunepolicy_test.go

@@ -0,0 +1,111 @@
+package migrations
+
+import (
+	"testing"
+
+	v1 "github.com/garethgeorge/backrest/gen/go/v1"
+	"google.golang.org/protobuf/encoding/protojson"
+	"google.golang.org/protobuf/proto"
+)
+
+func Test001Migration(t *testing.T) {
+	cases := []struct {
+		name   string
+		config string
+		want   *v1.Config
+	}{
+		{
+			name: "time bucketed policy",
+			config: `{
+				"plans": [
+					{
+						"retention": {
+							"keepHourly": 1,
+							"keepDaily": 2,
+							"keepWeekly": 3,
+							"keepMonthly": 4,
+							"keepYearly": 5
+						}
+					}
+				]
+			}`,
+			want: &v1.Config{
+				Plans: []*v1.Plan{
+					{
+						Retention: &v1.RetentionPolicy{
+							Policy: &v1.RetentionPolicy_PolicyTimeBucketed{
+								PolicyTimeBucketed: &v1.RetentionPolicy_TimeBucketedCounts{
+									Hourly:  1,
+									Daily:   2,
+									Weekly:  3,
+									Monthly: 4,
+									Yearly:  5,
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "keep all policy",
+			config: `{
+				"plans": [
+					{
+						"retention": {}
+					}
+				]
+			}`,
+			want: &v1.Config{
+				Plans: []*v1.Plan{
+					{
+						Retention: &v1.RetentionPolicy{
+							Policy: &v1.RetentionPolicy_PolicyKeepAll{
+								PolicyKeepAll: true,
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "keep by count",
+			config: `{
+				"plans": [
+					{
+						"retention": {
+							"keepLastN": 5
+						}
+					}
+				]
+			}`,
+			want: &v1.Config{
+				Plans: []*v1.Plan{
+					{
+						Retention: &v1.RetentionPolicy{
+							Policy: &v1.RetentionPolicy_PolicyKeepLastN{
+								PolicyKeepLastN: 5,
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			config := v1.Config{}
+			err := protojson.Unmarshal([]byte(tc.config), &config)
+			if err != nil {
+				t.Fatalf("failed to unmarshal config: %v", err)
+			}
+
+			migration001PrunePolicy(&config)
+
+			if !proto.Equal(&config, tc.want) {
+				t.Errorf("got: %+v, want: %+v", &config, tc.want)
+			}
+		})
+	}
+}

internal/config/migrations/migrations.go

@@ -0,0 +1,10 @@
+package migrations
+
+import v1 "github.com/garethgeorge/backrest/gen/go/v1"
+
+func ApplyMigrations(config *v1.Config) {
+	if config.Version <= 1 {
+		migration001PrunePolicy(config)
+	}
+	config.Version = 1
+}