feat(hosting): --hostname names the app's Cloud Run service on GCP

packages/reflex-hosting-cli/news/+gcp-service-name-from-hostname.feature.md

@@ -0,0 +1 @@
+On the deploy that first lands an app on GCP, `--hostname` now doubles as the app's Cloud Run service name, so the service in the customer's console reads like the app's URL instead of `app-<uuid>`. A hostname the service-name grammar refuses (leading digit, over 49 characters, or the reserved `app-<uuid>` shape) is skipped with a note and the server generates a name from the app name; later GCP deploys never send one, since the name is pinned to the live service.

packages/reflex-hosting-cli/src/reflex_cli/utils/hosting.py

@@ -1152,6 +1152,7 @@ def set_app_provider(
     provider: str,
     client: AuthenticatedClient,
     provider_account_id: str | None = None,
+    service_name: str | None = None,
 ) -> str:
     """Choose which hosting platform an app deploys to.
 
@@ -1168,6 +1169,9 @@ def set_app_provider(
             through (GCP only). None keeps the connection the app already has
             when it stays on GCP, and means the org's default connection when
             GCP is first chosen.
+        service_name: The Cloud Run service name the app deploys as (GCP only).
+            None keeps the app's current name, or lets the server mint one from
+            the app name; the server refuses a change once the app has deployed.
 
     Returns:
         The provider now set on the app, or a ``"... failed: ..."`` string on
@@ -1184,6 +1188,8 @@ def set_app_provider(
     payload: dict[str, Any] = {"provider": provider}
     if provider_account_id is not None:
         payload["provider_account_id"] = provider_account_id
+    if service_name is not None:
+        payload["service_name"] = service_name
     response = httpx.post(
         urljoin(constants.Hosting.HOSTING_SERVICE, f"/api/v1/apps/{app_id}/provider"),
         json=payload,

packages/reflex-hosting-cli/src/reflex_cli/v2/cli.py

@@ -7,8 +7,10 @@
 import json
 import logging
 import os
+import re
 import shutil
 import tempfile
+import uuid
 from collections.abc import Callable, Iterator
 from pathlib import Path
 from typing import Any
@@ -128,8 +130,62 @@ def _resolve_gcp_connection(
     return match
 
 
+# Cloud Run's service name grammar: lowercase, starts with a letter, ends
+# alphanumeric, at most 49 characters. Mirrors the server's validation so a
+# hostname that cannot be a service name is skipped here (the server mints one)
+# instead of failing the deploy.
+_GCP_SERVICE_NAME_RE = re.compile(r"^[a-z]([-a-z0-9]*[a-z0-9])?$")
+_GCP_SERVICE_NAME_MAX_LENGTH = 49
+
+
+def _gcp_service_name_from_hostname(hostname: str | None) -> str | None:
+    """The --hostname value as a Cloud Run service name, if it can be one.
+
+    On the first deploy to GCP the hostname doubles as the app's Cloud Run
+    service name, so the service in the customer's console reads like the app's
+    URL. A hostname the service-name grammar refuses (too long, leading digit,
+    or the reserved ``app-<uuid>`` shape) is skipped with a note rather than
+    failing the deploy — the server then mints a name from the app name.
+
+    Args:
+        hostname: The ``--hostname`` value, if the user passed one.
+
+    Returns:
+        The service name to request, or None to let the server choose.
+
+    """
+    if not hostname:
+        return None
+    name = hostname.strip().lower()
+    reserved = False
+    if name.startswith("app-"):
+        try:
+            uuid.UUID(name.removeprefix("app-"))
+            reserved = True
+        except ValueError:
+            reserved = False
+    if (
+        not name
+        or len(name) > _GCP_SERVICE_NAME_MAX_LENGTH
+        or not _GCP_SERVICE_NAME_RE.match(name)
+        or reserved
+    ):
+        logger.info(
+            f"The hostname '{hostname}' cannot be used as the Cloud Run service "
+            "name (lowercase letters, digits and hyphens, starting with a "
+            f"letter, at most {_GCP_SERVICE_NAME_MAX_LENGTH} characters); one "
+            "will be generated from the app name."
+        )
+        return None
+    return name
+
+
 def _pin_app_provider(
-    app: dict[str, Any], target: str, connection: dict[str, Any] | None, client: Any
+    app: dict[str, Any],
+    target: str,
+    connection: dict[str, Any] | None,
+    client: Any,
+    service_name: str | None = None,
 ) -> None:
     """Write the app's provider (and connection), aborting the deploy on refusal.
 
@@ -138,6 +194,8 @@ def _pin_app_provider(
         target: The backend provider value to pin.
         connection: The GCP connection to deploy through, if one was named.
         client: The authenticated client.
+        service_name: The Cloud Run service name to request (GCP only); None
+            keeps the app's current name or lets the server mint one.
 
     Raises:
         Exit: If the server refused the change.
@@ -150,6 +208,7 @@ def _pin_app_provider(
         target,
         client=client,
         provider_account_id=str(connection["id"]) if connection else None,
+        service_name=service_name,
     )
     if isinstance(result, str) and result.startswith("set provider failed"):
         logger.error(result)
@@ -163,6 +222,7 @@ def _resolve_deploy_provider(
     app_was_created: bool,
     client: Any,
     gcp_connection: str | None = None,
+    hostname: str | None = None,
 ) -> str | None:
     """Resolve and pin the hosting provider for this deploy.
 
@@ -182,6 +242,10 @@ def _resolve_deploy_provider(
             connections to deploy through. Omitted leaves the app on the
             connection it already has, or the org's default the first time it
             targets GCP.
+        hostname: The ``--hostname`` value. When this deploy is what first
+            lands the app on GCP, it doubles as the requested Cloud Run service
+            name; on later GCP deploys the name is already pinned to the live
+            service, so it is not sent.
 
     Returns:
         The backend provider value in effect (Reflex Cloud's default or GCP), or
@@ -253,9 +317,19 @@ def _resolve_deploy_provider(
             logger.info("Deployment cancelled.")
             raise click.exceptions.Exit(0)
 
-    _pin_app_provider(app, target, connection, client)
+    # Only this pin — the one that first lands the app on GCP — carries a
+    # service name. It is the moment the server would mint one, and the only
+    # time a request cannot collide with a name already serving traffic.
+    service_name = (
+        _gcp_service_name_from_hostname(hostname)
+        if target == hosting.PROVIDER_GCP
+        else None
+    )
+    _pin_app_provider(app, target, connection, client, service_name=service_name)
     via = f" through connection '{connection.get('name')}'" if connection else ""
     logger.info(f"Deploying to {hosting.provider_display_name(target)}{via}.")
+    if service_name:
+        logger.info(f"Requested Cloud Run service name '{service_name}'.")
     return target
 
 
@@ -483,7 +557,9 @@ def deploy(
         project: The project to deploy to.
         envs: The environment variables to set.
         vmtype: The VM type to allocate.
-        hostname: The hostname to use for the frontend.
+        hostname: The hostname to use for the frontend. On the deploy that
+            first lands the app on GCP it also names the app's Cloud Run
+            service, when the service-name grammar allows it.
         interactive: Whether to use interactive mode.
         envfile: The path to an env file to use. Will override any envs set manually.
         loglevel: The log level to use.
@@ -748,6 +824,7 @@ def deploy(
         app_was_created=app_was_created,
         client=authenticated_client,
         gcp_connection=gcp_connection,
+        hostname=hostname,
     )
     # A destructive provider switch on an already-deployed app tears its old
     # resources down; remember what to restore to if a later step fails.

packages/reflex-hosting-cli/src/reflex_cli/v2/deploy.py

@@ -59,7 +59,8 @@
 )
 @click.option(
     "--hostname",
-    help="The hostname of the frontend.",
+    help="The hostname of the frontend. On the deploy that first lands the "
+    "app on GCP, it also names the app's Cloud Run service.",
 )
 @click.option(
     "--provider",

tests/units/reflex_cli/utils/test_hosting.py

@@ -694,6 +694,20 @@ def test_set_app_provider_forwards_connection(mocker: MockerFixture):
     }
 
 
+def test_set_app_provider_forwards_service_name(mocker: MockerFixture):
+    """A requested Cloud Run service name rides along as service_name."""
+    mock_post = mocker.patch(
+        "httpx.post", return_value=_ok(mocker, {"provider": "gcp"})
+    )
+    assert set_app_provider(
+        "app-1", "gcp", _CLIENT, service_name="sales-dashboard"
+    ) == ("gcp")
+    assert mock_post.call_args.kwargs["json"] == {
+        "provider": "gcp",
+        "service_name": "sales-dashboard",
+    }
+
+
 def test_set_app_full_deploy_success(mocker: MockerFixture):
     """The mode change posts to the app's full_deploy endpoint."""
     mock_post = mocker.patch(

tests/units/reflex_cli/v2/test_cli.py

@@ -1463,10 +1463,80 @@ def test_resolve_deploy_provider_explicit_gcp_switches(mocker: MockFixture):
     )
     assert result == "gcp"
     mock_set.assert_called_once_with(
-        "app-1", "gcp", client=client, provider_account_id=None
+        "app-1", "gcp", client=client, provider_account_id=None, service_name=None
     )
 
 
+def test_resolve_deploy_provider_hostname_names_the_gcp_service(
+    mocker: MockFixture,
+):
+    """On the deploy that first lands on GCP, --hostname doubles as the service name."""
+    client = hosting.AuthenticatedClient(token="t", validated_data={})
+    mock_set = mocker.patch(
+        "reflex_cli.utils.hosting.set_app_provider", return_value="gcp"
+    )
+    app = {"id": "app-1", "name": "myapp", "provider": "fly"}
+    result = cli._resolve_deploy_provider(
+        app,
+        "gcp",
+        interactive=False,
+        app_was_created=True,
+        client=client,
+        hostname="Sales-Dashboard",
+    )
+    assert result == "gcp"
+    # Lowercased into the service-name grammar before it is sent.
+    mock_set.assert_called_once_with(
+        "app-1",
+        "gcp",
+        client=client,
+        provider_account_id=None,
+        service_name="sales-dashboard",
+    )
+
+
+def test_resolve_deploy_provider_unusable_hostname_lets_the_server_mint(
+    mocker: MockFixture,
+):
+    """A hostname the service-name grammar refuses is skipped, not fatal."""
+    client = hosting.AuthenticatedClient(token="t", validated_data={})
+    mock_set = mocker.patch(
+        "reflex_cli.utils.hosting.set_app_provider", return_value="gcp"
+    )
+    app = {"id": "app-1", "name": "myapp", "provider": "fly"}
+    result = cli._resolve_deploy_provider(
+        app,
+        "gcp",
+        interactive=False,
+        app_was_created=True,
+        client=client,
+        # Valid DNS label, invalid Cloud Run service name (leading digit).
+        hostname="2048game",
+    )
+    assert result == "gcp"
+    mock_set.assert_called_once_with(
+        "app-1", "gcp", client=client, provider_account_id=None, service_name=None
+    )
+
+
+def test_gcp_service_name_from_hostname_grammar():
+    """Only hostnames Cloud Run would accept as service names pass through."""
+    assert cli._gcp_service_name_from_hostname("sales-dashboard") == "sales-dashboard"
+    assert cli._gcp_service_name_from_hostname("MyApp") == "myapp"
+    assert cli._gcp_service_name_from_hostname(None) is None
+    assert cli._gcp_service_name_from_hostname("") is None
+    assert cli._gcp_service_name_from_hostname("2048game") is None
+    assert cli._gcp_service_name_from_hostname("-dash") is None
+    assert cli._gcp_service_name_from_hostname("dash-") is None
+    assert cli._gcp_service_name_from_hostname("a" * 50) is None
+    # The derived-name namespace of apps that store no name is reserved.
+    assert (
+        cli._gcp_service_name_from_hostname("app-8b2f4a1c-1234-5678-9abc-def012345678")
+        is None
+    )
+    assert cli._gcp_service_name_from_hostname("app-metrics") == "app-metrics"
+
+
 def test_resolve_deploy_provider_reflex_cloud_no_switch(mocker: MockFixture):
     """--provider reflex-cloud on a fly app is a no-op (already Reflex Cloud)."""
     client = hosting.AuthenticatedClient(token="t", validated_data={})
@@ -1616,7 +1686,7 @@ def test_resolve_deploy_provider_named_connection_is_pinned(mocker: MockFixture)
 
     assert result == "gcp"
     mock_set.assert_called_once_with(
-        "app-1", "gcp", client=client, provider_account_id="conn-2"
+        "app-1", "gcp", client=client, provider_account_id="conn-2", service_name=None
     )
 
 
@@ -1645,7 +1715,41 @@ def test_resolve_deploy_provider_repoints_without_a_provider_switch(
 
     assert result == "gcp"
     mock_set.assert_called_once_with(
-        "app-1", "gcp", client=client, provider_account_id="conn-2"
+        "app-1", "gcp", client=client, provider_account_id="conn-2", service_name=None
+    )
+
+
+def test_resolve_deploy_provider_gcp_redeploy_keeps_the_pinned_name(
+    mocker: MockFixture,
+):
+    """An app already on GCP never re-sends a service name.
+
+    The name is pinned to a live service by then, so a --hostname on a later
+    deploy must not reach the server as a rename request.
+    """
+    client = hosting.AuthenticatedClient(token="t", validated_data={})
+    mocker.patch(
+        "reflex_cli.utils.hosting.list_gcp_connections",
+        return_value=[{"id": "conn-2", "name": "eu-prod"}],
+    )
+    mock_set = mocker.patch(
+        "reflex_cli.utils.hosting.set_app_provider", return_value="gcp"
+    )
+    app = {"id": "app-1", "name": "myapp", "provider": "gcp"}
+
+    result = cli._resolve_deploy_provider(
+        app,
+        "gcp",
+        interactive=False,
+        app_was_created=False,
+        client=client,
+        gcp_connection="eu-prod",
+        hostname="sales-dashboard",
+    )
+
+    assert result == "gcp"
+    mock_set.assert_called_once_with(
+        "app-1", "gcp", client=client, provider_account_id="conn-2", service_name=None
     )