feat(persistence): add PropertyRepository.PutIfAbsent

model/properties.go

@@ -4,6 +4,7 @@ import "context"
 
 type PropertyRepository interface {
 	Put(ctx context.Context, id string, value string) error
+	PutIfAbsent(ctx context.Context, id string, value string) error
 	Get(ctx context.Context, id string) (string, error)
 	Delete(ctx context.Context, id string) error
 	DefaultGet(ctx context.Context, id string, defaultValue string) (string, error)

persistence/property_repository.go

@@ -34,6 +34,12 @@ func (r propertyRepository) Put(ctx context.Context, id string, value string) er
 	return err
 }
 
+func (r propertyRepository) PutIfAbsent(ctx context.Context, id string, value string) error {
+	insert := Insert(r.tableName).Columns("id", "value").Values(id, value).Options("OR IGNORE")
+	_, err := r.executeSQL(ctx, insert)
+	return err
+}
+
 func (r propertyRepository) Get(ctx context.Context, id string) (string, error) {
 	sel := Select("value").From(r.tableName).Where(Eq{"id": id})
 	resp := struct {

persistence/property_repository_test.go

@@ -33,4 +33,10 @@ var _ = Describe("Property Repository", func() {
 	It("returns a default value if property does not exist", func() {
 		Expect(pr.DefaultGet(ctx, "2", "default")).To(Equal("default"))
 	})
+
+	It("PutIfAbsent inserts once and never overwrites", func() {
+		Expect(pr.PutIfAbsent(ctx, "pia", "first")).To(Succeed())
+		Expect(pr.PutIfAbsent(ctx, "pia", "second")).To(Succeed())
+		Expect(pr.Get(ctx, "pia")).To(Equal("first"))
+	})
 })

tests/mock_property_repo.go

@@ -27,6 +27,17 @@ func (p *MockedPropertyRepo) Put(_ context.Context, id string, value string) err
 	return nil
 }
 
+func (p *MockedPropertyRepo) PutIfAbsent(_ context.Context, id string, value string) error {
+	if p.Error != nil {
+		return p.Error
+	}
+	p.init()
+	if _, ok := p.Data[id]; !ok {
+		p.Data[id] = value
+	}
+	return nil
+}
+
 func (p *MockedPropertyRepo) Get(_ context.Context, id string) (string, error) {
 	if p.Error != nil {
 		return "", p.Error