Register PostgreSQL types once on start with guest user

There are types inaccessible to the authenticator role, such as
redsys_request, that can not be registered because that roles is unable
to get the OID of.

I could have moved these types to the public schema, but then it would
seem pointless to have a separate schema.

pkg/database/db.go

@@ -15,21 +15,30 @@ import (
 	"github.com/jackc/pgx/v4/pgxpool"
 )
 
+const (
+	searchPathQuery = "set search_path to camper, public"
+)
+
 func ErrorIsNotFound(err error) bool {
 	return errors.Is(err, pgx.ErrNoRows)
 }
 
 func New(ctx context.Context, connString string) (*DB, error) {
+	// Connect once with an “elevated” user to register types in camper schema
+	if err := registerTypes(ctx, connString); err != nil {
+		return nil, err
+	}
+
 	config, err := pgxpool.ParseConfig(connString)
 	if err != nil {
 		return nil, err
 	}
 
 	config.AfterConnect = func(ctx context.Context, conn *pgx.Conn) error {
-		if _, err := conn.Exec(ctx, "set search_path to camper, public"); err != nil {
+		if _, err := conn.Exec(ctx, searchPathQuery); err != nil {
 			return err
 		}
-		return registerTypes(ctx, conn)
+		return registerConnectionTypes(ctx, conn)
 	}
 
 	config.AfterRelease = func(conn *pgx.Conn) bool {
@@ -44,6 +53,7 @@ func New(ctx context.Context, connString string) (*DB, error) {
 	if err != nil {
 		return nil, err
 	}
+
 	return &DB{pool}, nil
 }
 

pkg/database/types.go

@@ -21,7 +21,26 @@ var (
 	oidCache = make(map[string]uint32)
 )
 
-func registerTypes(ctx context.Context, conn *pgx.Conn) error {
+func registerTypes(ctx context.Context, connString string) error {
+	conn, err := pgx.Connect(ctx, connString)
+	if err != nil {
+		return err
+	}
+	defer conn.Close(context.Background())
+
+	if _, err := conn.Exec(ctx, "set role to guest"); err != nil {
+		return err
+	}
+	if _, err := conn.Exec(ctx, searchPathQuery); err != nil {
+		return err
+	}
+	if err := registerConnectionTypes(ctx, conn); err != nil {
+		return err
+	}
+	return nil
+}
+
+func registerConnectionTypes(ctx context.Context, conn *pgx.Conn) error {
 	uriOID, err := registerType(ctx, conn, &pgtype.Text{}, "uri")
 	if err != nil {
 		return err