set project and instances to default for external hosts (#41)

* set  project and instances to default for external hosts

* readme typo

* set config as default project and instance for external host

* unit tests added

* corrected project assignment

* constants added for external host properties

* constants added for external host in schema convertor

Author: sagnghos

schema_converter/README.md

@@ -65,6 +65,10 @@ go run cql_to_spanner_schema_converter.go --project <PROJECT_ID> --instance <INS
 - `[--table]`: Optional flag to specify different table name for TableConfigurations.
 - `[--enableUsingTimestamp]`: Optional flag to enable 'Using Timestamp' features, default is false.
 - `[--enableUsingTTL]`: Optional flag to enable 'Using TTL' features, default is false.
+- `[--usePlainText]`: Optional flag to enable plain text connection for external host, default is false.
+- `[--caCertificate]`: Optional flag to specify the CA certificate file path required for TLS/mTLS connection for external hosts.
+- `[--clientCertificate]`: Optional flag to specify the client certificate file path required for mTLS connection for external hosts.
+- `[--clientKey]`: Optional flag to specify the client key file path required for mTLS connection for external hosts.
 
 ### 2. Example Commands
 

schema_converter/cql_to_spanner_schema_converter.go

@@ -20,6 +20,7 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"regexp"
 	"time"
 
 	"bufio"
@@ -38,6 +39,11 @@ import (
 	"google.golang.org/grpc/credentials/insecure"
 )
 
+const (
+	ExternalHostProjectID  = "default"
+	ExternalHostInstanceID = "default"
+)
+
 type ColumnMetadata struct {
 	ColumnName   string
 	CQLType      string
@@ -150,10 +156,16 @@ func main() {
 	caCertificate := flag.String("caCertificate", "", "The CA certificate file to use for TLS")
 	clientCertificate := flag.String("clientCertificate", "", "The client certificate to establish mTLS for external hosts")
 	clientKey := flag.String("clientKey", "", "The client key to establish mTLS for external hosts")
-	externalHost := flag.Bool("externalHost", false, "Whether connection needs to be established with an externalHost")
 
 	flag.Parse()
 
+	isExternalHost := (*endpoint != "" && !regexp.MustCompile(`.*\.googleapis\.com.*`).MatchString(*endpoint))
+
+	if isExternalHost {
+		*projectID = ExternalHostProjectID
+		*instanceID = ExternalHostInstanceID
+	}
+
 	// Check if all required flags are provided
 	checkMissingFlags := func() []string {
 		missingFlags := []string{}
@@ -181,7 +193,7 @@ func main() {
 	}
 
 	// Ensure that GCP credentials are set except for spanner external host connections
-	if !*externalHost {
+	if !isExternalHost {
 		if err := checkGCPCredentials(); err != nil {
 			log.Fatalf("Error: %v", err)
 		}

third_party/datastax/proxy/defaults.go

@@ -1,13 +1,18 @@
 package proxy
 
-import "fmt"
+import (
+	"fmt"
+	"regexp"
+)
 
 // Defaults for Spanner Settings.
 const (
 	DefaultSpannerGrpcChannels = 4
 	DefaultSpannerMinSession   = 100
 	DefaultSpannerMaxSession   = 400
 	DefaultConfigTableName     = "TableConfigurations"
+	ExternalHostProjectID      = "default"
+	ExternalHostInstanceID     = "default"
 )
 
 // ApplyDefaults applies default values to the configuration after it is loaded
@@ -50,6 +55,10 @@ func ValidateAndApplyDefaults(cfg *UserConfig) error {
 		if cfg.Listeners[i].Spanner.DatabaseID == "" {
 			return fmt.Errorf("database id is not defined for listener %s %d", cfg.Listeners[i].Name, cfg.Listeners[i].Port)
 		}
+		if cfg.CassandraToSpannerConfigs.Endpoint != "" && !regexp.MustCompile(`.*\.googleapis\.com.*`).MatchString(cfg.CassandraToSpannerConfigs.Endpoint) {
+			cfg.Listeners[i].Spanner.ProjectID = ExternalHostProjectID
+			cfg.Listeners[i].Spanner.InstanceID = ExternalHostInstanceID
+		}
 		if cfg.Listeners[i].Spanner.ProjectID == "" {
 			if cfg.CassandraToSpannerConfigs.ProjectID == "" {
 				return fmt.Errorf("project id is not defined for listener %s %d", cfg.Listeners[i].Name, cfg.Listeners[i].Port)

third_party/datastax/proxy/defaults_test.go

@@ -169,3 +169,61 @@ func TestValidateAndApplyDefaultsMissingDatabaseID(t *testing.T) {
 		t.Errorf("Expected error for missing DatabaseID, got: %v", err)
 	}
 }
+
+func TestValidateExternalHostEndpointSetsDefaults(t *testing.T) {
+	cfg := &UserConfig{
+		Listeners: []Listener{
+			{
+				Name: "Listener1",
+				Port: 8080,
+				Spanner: Spanner{
+					DatabaseID: "db-1",
+					InstanceID: "",
+					ProjectID:  "",
+				},
+			},
+		},
+		CassandraToSpannerConfigs: CassandraToSpannerConfigs{
+			Endpoint:  "localhost:9090", // ExternalHost endpoint
+			ProjectID: "",
+		},
+	}
+
+	err := ValidateAndApplyDefaults(cfg)
+	if err != nil {
+		t.Errorf("Did not expect an error, got: %v", err)
+	}
+
+	l := cfg.Listeners[0]
+	if l.Spanner.InstanceID != "default" {
+		t.Errorf("Expected InstanceID to be 'default', got: %s", l.Spanner.InstanceID)
+	}
+	if l.Spanner.ProjectID != "default" {
+		t.Errorf("Expected ProjectID to be 'default', got: %s", cfg.CassandraToSpannerConfigs.ProjectID)
+	}
+}
+
+func TestValidateCloudSpannerEndpointMissingProjectAndInstance(t *testing.T) {
+	cfg := &UserConfig{
+		Listeners: []Listener{
+			{
+				Name: "Listener1",
+				Port: 8080,
+				Spanner: Spanner{
+					DatabaseID: "db-1",
+					InstanceID: "",
+					ProjectID:  "",
+				},
+			},
+		},
+		CassandraToSpannerConfigs: CassandraToSpannerConfigs{
+			Endpoint:  "spanner.googleapis.com:443", // Cloud Spanner endpoint
+			ProjectID: "",                           // Empty ProjectID
+		},
+	}
+	err := ValidateAndApplyDefaults(cfg)
+	expectedError := "project id is not defined for listener Listener1 8080"
+	if err == nil || err.Error() != expectedError {
+		t.Errorf("Expected error for missing ProjectID and InstanceID with Cloud Spanner endpoint, got: %v", err)
+	}
+}