Add spanner emulator env var detection

internal/datastore/spanner/migrations/driver.go

@@ -16,6 +16,7 @@ import (
 const (
 	tableSchemaVersion = "schema_version"
 	colVersionNum      = "version_num"
+	emulatorSettingKey = "SPANNER_EMULATOR_HOST"
 )
 
 // SpannerMigrationDriver can migrate a Cloud Spanner instance
@@ -26,10 +27,13 @@ type SpannerMigrationDriver struct {
 }
 
 // NewSpannerDriver returns a migration driver for the given Cloud Spanner instance
-func NewSpannerDriver(database, credentialsFilePath string) (SpannerMigrationDriver, error) {
+func NewSpannerDriver(database, credentialsFilePath, emulatorHost string) (SpannerMigrationDriver, error) {
 	ctx := context.Background()
 
-	log.Info().Str("spanner-emulator-host", os.Getenv("SPANNER_EMULATOR_HOST")).Msg("spanner emulator")
+	if len(emulatorHost) > 0 {
+		os.Setenv(emulatorSettingKey, emulatorHost)
+	}
+	log.Info().Str("spanner-emulator-host", os.Getenv(emulatorSettingKey)).Msg("spanner emulator")
 	log.Info().Str("credentials", credentialsFilePath).Str("db", database).Msg("connecting")
 	client, err := spanner.NewClient(ctx, database, option.WithCredentialsFile(credentialsFilePath))
 	if err != nil {

internal/datastore/spanner/options.go

@@ -14,6 +14,7 @@ type spannerOptions struct {
 	gcInterval                  time.Duration
 	maxRetries                  int
 	credentialsFilePath         string
+	emulatorHost                string
 }
 
 const (
@@ -135,3 +136,11 @@ func CredentialsFile(path string) Option {
 		so.credentialsFilePath = path
 	}
 }
+
+// EmulatorHost is the URI of a Spanner emulator to connect to for
+// development and testing use
+func EmulatorHost(uri string) Option {
+	return func(so *spannerOptions) {
+		so.emulatorHost = uri
+	}
+}

internal/datastore/spanner/spanner.go

@@ -58,6 +58,10 @@ func NewSpannerDatastore(database string, opts ...Option) (datastore.Datastore,
 		return nil, fmt.Errorf(errUnableToInstantiate, err)
 	}
 
+	if len(config.emulatorHost) > 0 {
+		os.Setenv("SPANNER_EMULATOR_HOST", config.emulatorHost)
+	}
+
 	config.gcInterval = common.WithJitter(0.2, config.gcInterval)
 	log.Info().Float64("factor", 0.2).Msg("gc configured with jitter")
 	log.Info().Str("spanner-emulator-host", os.Getenv("SPANNER_EMULATOR_HOST")).Msg("spanner emulator")
@@ -104,7 +108,7 @@ func (sd spannerDatastore) IsReady(ctx context.Context) (bool, error) {
 		return false, fmt.Errorf("invalid head migration found for postgres: %w", err)
 	}
 
-	currentRevision, err := migrations.NewSpannerDriver(sd.client.DatabaseName(), sd.config.credentialsFilePath)
+	currentRevision, err := migrations.NewSpannerDriver(sd.client.DatabaseName(), sd.config.credentialsFilePath, sd.config.emulatorHost)
 	if err != nil {
 		return false, err
 	}

internal/testserver/datastore/spanner.go

@@ -129,7 +129,7 @@ func (b *spannerTest) NewDatabase(t testing.TB) string {
 func (b *spannerTest) NewDatastore(t testing.TB, initFunc InitFunc) datastore.Datastore {
 	db := b.NewDatabase(t)
 
-	migrationDriver, err := migrations.NewSpannerDriver(db, "")
+	migrationDriver, err := migrations.NewSpannerDriver(db, "", os.Getenv("SPANNER_EMULATOR_HOST"))
 	require.NoError(t, err)
 
 	err = migrations.SpannerMigrations.Run(migrationDriver, migrate.Head, migrate.LiveRun)

pkg/cmd/datastore/datastore.go

@@ -77,6 +77,7 @@ type Config struct {
 
 	// Spanner
 	SpannerCredentialsFile string
+	SpannerEmulatorHost    string
 
 	// MySQL
 	TablePrefix string
@@ -113,6 +114,7 @@ func RegisterDatastoreFlags(cmd *cobra.Command, opts *Config) {
 	cmd.Flags().StringVar(&opts.OverlapStrategy, "datastore-tx-overlap-strategy", "static", `strategy to generate transaction overlap keys ("prefix", "static", "insecure") (cockroach driver only)`)
 	cmd.Flags().StringVar(&opts.OverlapKey, "datastore-tx-overlap-key", "key", "static key to touch when writing to ensure transactions overlap (only used if --datastore-tx-overlap-strategy=static is set; cockroach driver only)")
 	cmd.Flags().StringVar(&opts.SpannerCredentialsFile, "datastore-spanner-credentials", "", "path to service account key credentials file with access to the cloud spanner instance")
+	cmd.Flags().StringVar(&opts.SpannerEmulatorHost, "datastore-spanner-emulator-host", "", "URI of spanner emulator instance used for development and testing (e.g. localhost:9010)")
 	cmd.Flags().StringVar(&opts.TablePrefix, "datastore-mysql-table-prefix", "", "prefix to add to the name of all SpiceDB database tables")
 
 	cmd.Flags().DurationVar(&opts.LegacyFuzzing, "datastore-revision-fuzzing-duration", -1, "amount of time to advertize stale revisions")
@@ -251,6 +253,7 @@ func newSpannerDatastore(opts Config) (datastore.Datastore, error) {
 		spanner.GCWindow(opts.GCWindow),
 		spanner.CredentialsFile(opts.SpannerCredentialsFile),
 		spanner.WatchBufferLength(opts.WatchBufferLength),
+		spanner.EmulatorHost(opts.SpannerEmulatorHost),
 	)
 }
 

pkg/cmd/migrate.go

@@ -21,6 +21,7 @@ func RegisterMigrateFlags(cmd *cobra.Command) {
 	cmd.Flags().String("datastore-engine", "memory", fmt.Sprintf(`type of datastore to initialize (%s)`, datastore.EngineOptions()))
 	cmd.Flags().String("datastore-conn-uri", "", `connection string used by remote datastores (e.g. "postgres://postgres:password@localhost:5432/spicedb")`)
 	cmd.Flags().String("datastore-spanner-credentials", "", "path to service account key credentials file with access to the cloud spanner instance")
+	cmd.Flags().String("datastore-spanner-emulator-host", "", "URI of spanner emulator instance used for development and testing (e.g. localhost:9010)")
 	cmd.Flags().String("datastore-mysql-table-prefix", "", "prefix to add to the name of all mysql database tables")
 }
 
@@ -65,7 +66,11 @@ func migrateRun(cmd *cobra.Command, args []string) error {
 
 		credFile := cobrautil.MustGetStringExpanded(cmd, "datastore-spanner-credentials")
 		var err error
-		migrationDriver, err = spannermigrations.NewSpannerDriver(dbURL, credFile)
+		emulatorHost, err := cmd.Flags().GetString("datastore-spanner-emulator-host")
+		if err != nil {
+			log.Fatal().Err(err).Msg("unable to get spanner emulator host")
+		}
+		migrationDriver, err = spannermigrations.NewSpannerDriver(dbURL, credFile, emulatorHost)
 		if err != nil {
 			log.Fatal().Err(err).Msg("unable to create migration driver")
 		}