feat: Add a global flag to enable multi-tenant support

When enabled the graph service refuses to start with the "ldap" backend.
Additional enforcements will follow in subsequent commits.

services/graph/pkg/config/parser/parse.go

@@ -42,6 +42,10 @@ func Validate(cfg *config.Config) error {
 		return shared.MissingJWTTokenError(cfg.Service.Name)
 	}
 
+	// ensure that the "cs3" identity backend is used in multi-tenant setups
+	if cfg.Commons.MultiTenantEnabled && cfg.Identity.Backend != "cs3" {
+		return fmt.Errorf("Multi-tenant support is enabled. The identity backend must be set to 'cs3' for the 'graph' service.")
+	}
 	if cfg.Identity.Backend == "ldap" {
 		if err := validateLDAPSettings(cfg); err != nil {
 			return err

services/graph/pkg/config/parser/parse_test.go

@@ -0,0 +1,63 @@
+package parser_test
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	"github.com/opencloud-eu/opencloud/pkg/shared"
+	"github.com/opencloud-eu/opencloud/services/graph/pkg/config"
+	"github.com/opencloud-eu/opencloud/services/graph/pkg/config/defaults"
+	"github.com/opencloud-eu/opencloud/services/graph/pkg/config/parser"
+)
+
+var _ = Describe("Validate", func() {
+	var cfg *config.Config
+
+	BeforeEach(func() {
+		cfg = defaults.DefaultConfig()
+		cfg.Application.ID = "graph-app-id"
+		cfg.ServiceAccount.ServiceAccountID = "graph-service-account"
+		cfg.ServiceAccount.ServiceAccountSecret = "graph-service-password"
+		cfg.Commons = &shared.Commons{
+			TokenManager: &shared.TokenManager{
+				JWTSecret: "jwt-secret",
+			},
+		}
+		defaults.EnsureDefaults(cfg)
+	})
+
+	When("multi-tenant support is disabled", func() {
+		It("should accept a setup with the 'cs3' identity backend", func() {
+			cfg.Identity.Backend = "cs3"
+			err := parser.Validate(cfg)
+			Expect(err).ToNot(HaveOccurred())
+		})
+		It("should accept a setup with the 'ldap' identity backend", func() {
+			cfg.Identity.Backend = "ldap"
+			// we need to set a password to pass validation
+			cfg.Identity.LDAP.BindPassword = "bind-password"
+			err := parser.Validate(cfg)
+			Expect(err).ToNot(HaveOccurred())
+		})
+	})
+
+	When("multi-tenant support is disabled", func() {
+		BeforeEach(func() {
+			cfg.Commons.MultiTenantEnabled = true
+		})
+		It("should accept a setup with the 'cs3' identity backend", func() {
+			cfg.Identity.Backend = "cs3"
+			err := parser.Validate(cfg)
+			Expect(err).ToNot(HaveOccurred())
+		})
+
+		It("should reject a setup with the 'ldap' identity backend", func() {
+			cfg.Identity.Backend = "ldap"
+			cfg.Identity.LDAP.BindPassword = "bind-password"
+			err := parser.Validate(cfg)
+			Expect(err).To(HaveOccurred())
+			Expect(err).To(MatchError(ContainSubstring("The identity backend must be set to 'cs3' for the 'graph' service.")))
+		})
+	})
+
+})

services/graph/pkg/config/parser/parser_suite_test.go

@@ -0,0 +1,13 @@
+package parser_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestParser(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Parser Suite")
+}