fix: allow session launcher parameters to be reset

Allows the API to accept None as input for args, command and the session
launcher resource class ID so that they can be reset to their defaults
in patch endpoints.

Author: olevski

components/renku_data_services/base_models/core.py

@@ -212,3 +212,17 @@ class Authenticator(Protocol[AnyAPIUser]):
     async def authenticate(self, access_token: str, request: Request) -> AnyAPIUser:
         """Validates the user credentials (i.e. we can say that the user is a valid Renku user)."""
         ...
+
+
+@dataclass(frozen=True, eq=True, kw_only=True)
+class Null:
+    """Parent class for distinguishing between None values."""
+
+    value: None = field(default=None, init=False, repr=False)
+
+
+@dataclass(frozen=True, eq=True, kw_only=True)
+class Reset(Null):
+    """Used to indicate a None value that has been deliberately set by the user or caller."""
+
+    ...

components/renku_data_services/session/blueprints.py

@@ -11,7 +11,7 @@
 import renku_data_services.base_models as base_models
 from renku_data_services.base_api.auth import authenticate, validate_path_project_id
 from renku_data_services.base_api.blueprint import BlueprintFactoryResponse, CustomBlueprint
-from renku_data_services.session import apispec, models
+from renku_data_services.session import apispec, converters, models
 from renku_data_services.session.db import SessionRepository
 
 
@@ -75,9 +75,11 @@ def patch(self) -> BlueprintFactoryResponse:
         async def _patch(
             _: Request, user: base_models.APIUser, environment_id: ULID, body: apispec.EnvironmentPatch
         ) -> JSONResponse:
-            body_dict = body.model_dump(exclude_none=True)
+            update = converters.environment_update_from_patch(body)
             environment = await self.session_repo.update_environment(
-                user=user, environment_id=environment_id, **body_dict
+                user=user,
+                environment_id=environment_id,
+                update=update,
             )
             return json(apispec.Environment.model_validate(environment).model_dump(exclude_none=True, mode="json"))
 
@@ -172,34 +174,14 @@ def patch(self) -> BlueprintFactoryResponse:
         async def _patch(
             _: Request, user: base_models.APIUser, launcher_id: ULID, body: apispec.SessionLauncherPatch
         ) -> JSONResponse:
-            body_dict = body.model_dump(exclude_none=True, mode="json")
             async with self.session_repo.session_maker() as session, session.begin():
                 current_launcher = await self.session_repo.get_launcher(user, launcher_id)
-                new_env: models.UnsavedEnvironment | None = None
-                if (
-                    isinstance(body.environment, apispec.EnvironmentPatchInLauncher)
-                    and current_launcher.environment.environment_kind == models.EnvironmentKind.GLOBAL
-                    and body.environment.environment_kind == apispec.EnvironmentKind.CUSTOM
-                ):
-                    # This means that the global environment is being swapped for a custom one,
-                    # so we have to create a brand new environment, but we have to validate here.
-                    validated_env = apispec.EnvironmentPostInLauncher.model_validate(body_dict.pop("environment"))
-                    new_env = models.UnsavedEnvironment(
-                        name=validated_env.name,
-                        description=validated_env.description,
-                        container_image=validated_env.container_image,
-                        default_url=validated_env.default_url,
-                        port=validated_env.port,
-                        working_directory=PurePosixPath(validated_env.working_directory),
-                        mount_directory=PurePosixPath(validated_env.mount_directory),
-                        uid=validated_env.uid,
-                        gid=validated_env.gid,
-                        environment_kind=models.EnvironmentKind(validated_env.environment_kind.value),
-                        args=validated_env.args,
-                        command=validated_env.command,
-                    )
+                update = converters.launcher_update_from_patch(body, current_launcher)
                 launcher = await self.session_repo.update_launcher(
-                    user=user, launcher_id=launcher_id, new_custom_environment=new_env, session=session, **body_dict
+                    user=user,
+                    launcher_id=launcher_id,
+                    session=session,
+                    update=update,
                 )
             return json(apispec.SessionLauncher.model_validate(launcher).model_dump(exclude_none=True, mode="json"))
 

components/renku_data_services/session/converters.py

@@ -0,0 +1,83 @@
+"""Code used to convert from/to apispec and models."""
+
+from pathlib import PurePosixPath
+
+from renku_data_services.base_models.core import Reset
+from renku_data_services.session import apispec, models
+
+
+def environment_update_from_patch(data: apispec.EnvironmentPatch) -> models.EnvironmentUpdate:
+    """Create an update object from an apispec or any other pydantic model."""
+    data_dict = data.model_dump(exclude_unset=True, mode="json")
+    working_directory: PurePosixPath | None = None
+    if data.working_directory is not None:
+        working_directory = PurePosixPath(data.working_directory)
+    mount_directory: PurePosixPath | None = None
+    if data.mount_directory is not None:
+        mount_directory = PurePosixPath(data.mount_directory)
+    # NOTE: If the args or command are present in the data_dict and they are None they were passed in by the user.
+    # The None specifically passed by the user indicates that the value should be removed from the DB.
+    args = Reset() if "args" in data_dict and data_dict["args"] is None else data.args
+    command = Reset() if "command" in data_dict and data_dict["command"] is None else data.command
+    return models.EnvironmentUpdate(
+        name=data.name,
+        description=data.description,
+        container_image=data.container_image,
+        default_url=data.default_url,
+        port=data.port,
+        working_directory=working_directory,
+        mount_directory=mount_directory,
+        uid=data.uid,
+        gid=data.gid,
+        args=args,
+        command=command,
+    )
+
+
+def launcher_update_from_patch(
+    data: apispec.SessionLauncherPatch,
+    current_launcher: models.SessionLauncher | None = None,
+) -> models.SessionLauncherUpdate:
+    """Create an update object from an apispec or any other pydantic model."""
+    data_dict = data.model_dump(exclude_unset=True, mode="json")
+    environment: str | models.EnvironmentUpdate | models.UnsavedEnvironment | None = None
+    if (
+        isinstance(data.environment, apispec.EnvironmentPatchInLauncher)
+        and current_launcher is not None
+        and current_launcher.environment.environment_kind == models.EnvironmentKind.GLOBAL
+        and data.environment.environment_kind == apispec.EnvironmentKind.CUSTOM
+    ):
+        # This means that the global environment is being swapped for a custom one,
+        # so we have to create a brand new environment, but we have to validate here.
+        validated_env = apispec.EnvironmentPostInLauncher.model_validate(data_dict["environment"])
+        environment = models.UnsavedEnvironment(
+            name=validated_env.name,
+            description=validated_env.description,
+            container_image=validated_env.container_image,
+            default_url=validated_env.default_url,
+            port=validated_env.port,
+            working_directory=PurePosixPath(validated_env.working_directory),
+            mount_directory=PurePosixPath(validated_env.mount_directory),
+            uid=validated_env.uid,
+            gid=validated_env.gid,
+            environment_kind=models.EnvironmentKind(validated_env.environment_kind.value),
+            args=validated_env.args,
+            command=validated_env.command,
+        )
+    elif isinstance(data.environment, apispec.EnvironmentPatchInLauncher):
+        environment = environment_update_from_patch(data.environment)
+    elif isinstance(data.environment, apispec.EnvironmentIdOnlyPatch):
+        environment = data.environment.id
+    resource_class_id: int | None | Reset = None
+    if "resource_class_id" in data_dict and data_dict["resource_class_id"] is None:
+        # NOTE: This means that the resource class set in the DB should be removed so that the
+        # default resource class currently set in the CRC will be used.
+        resource_class_id = Reset()
+    else:
+        resource_class_id = data_dict.get("resource_class_id")
+    return models.SessionLauncherUpdate(
+        name=data_dict.get("name"),
+        description=data_dict.get("description"),
+        environment=environment,
+        resource_class_id=resource_class_id,
+    )

components/renku_data_services/session/db.py

@@ -5,7 +5,6 @@
 from collections.abc import Callable
 from contextlib import AbstractAsyncContextManager, nullcontext
 from datetime import UTC, datetime
-from typing import Any
 
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -15,6 +14,7 @@
 from renku_data_services import errors
 from renku_data_services.authz.authz import Authz, ResourceType
 from renku_data_services.authz.models import Scope
+from renku_data_services.base_models.core import Reset
 from renku_data_services.crc.db import ResourcePoolRepository
 from renku_data_services.session import models
 from renku_data_services.session import orm as schemas
@@ -101,53 +101,59 @@ async def insert_environment(
             env = await self.__insert_environment(user, session, new_environment)
             return env.dump()
 
-    async def __update_environment(
+    def __update_environment(
         self,
-        user: base_models.APIUser,
-        session: AsyncSession,
-        environment_id: ULID,
-        kind: models.EnvironmentKind,
-        **kwargs: dict,
-    ) -> models.Environment:
-        res = await session.scalars(
-            select(schemas.EnvironmentORM)
-            .where(schemas.EnvironmentORM.id == str(environment_id))
-            .where(schemas.EnvironmentORM.environment_kind == kind.value)
-        )
-        environment = res.one_or_none()
-        if environment is None:
-            raise errors.MissingResourceError(message=f"Session environment with id '{environment_id}' does not exist.")
-
-        for key, value in kwargs.items():
-            # NOTE: Only some fields can be edited
-            if key in [
-                "name",
-                "description",
-                "container_image",
-                "default_url",
-                "port",
-                "working_directory",
-                "mount_directory",
-                "uid",
-                "gid",
-                "args",
-                "command",
-            ]:
-                setattr(environment, key, value)
-
-        return environment.dump()
+        environment: schemas.EnvironmentORM,
+        update: models.EnvironmentUpdate,
+    ) -> None:
+        # NOTE: this is more verbose than a loop and setattr but this way we get mypy type checks
+        if update.name is not None:
+            environment.name = update.name
+        if update.description is not None:
+            environment.description = update.description
+        if update.container_image is not None:
+            environment.container_image = update.container_image
+        if update.default_url is not None:
+            environment.default_url = update.default_url
+        if update.port is not None:
+            environment.port = update.port
+        if update.working_directory is not None:
+            environment.working_directory = update.working_directory
+        if update.mount_directory is not None:
+            environment.mount_directory = update.mount_directory
+        if update.uid is not None:
+            environment.uid = update.uid
+        if update.gid is not None:
+            environment.gid = update.gid
+        if isinstance(update.args, Reset):
+            environment.args = None
+        elif isinstance(update.args, list):
+            environment.args = update.args
+        if isinstance(update.command, Reset):
+            environment.command = None
+        elif isinstance(update.command, list):
+            environment.command = update.command
 
     async def update_environment(
-        self, user: base_models.APIUser, environment_id: ULID, **kwargs: dict
+        self, user: base_models.APIUser, environment_id: ULID, update: models.EnvironmentUpdate
     ) -> models.Environment:
         """Update a global session environment entry."""
         if not user.is_admin:
             raise errors.UnauthorizedError(message="You do not have the required permissions for this operation.")
 
         async with self.session_maker() as session, session.begin():
-            return await self.__update_environment(
-                user, session, environment_id, models.EnvironmentKind.GLOBAL, **kwargs
+            res = await session.scalars(
+                select(schemas.EnvironmentORM)
+                .where(schemas.EnvironmentORM.id == str(environment_id))
+                .where(schemas.EnvironmentORM.environment_kind == models.EnvironmentKind.GLOBAL)
             )
+            environment = res.one_or_none()
+            if environment is None:
+                raise errors.MissingResourceError(
+                    message=f"Session environment with id '{environment_id}' does not exist."
+                )
+            self.__update_environment(environment, update)
+            return environment.dump()
 
     async def delete_environment(self, user: base_models.APIUser, environment_id: ULID) -> None:
         """Delete a global session environment entry."""
@@ -300,9 +306,8 @@ async def update_launcher(
         self,
         user: base_models.APIUser,
         launcher_id: ULID,
-        new_custom_environment: models.UnsavedEnvironment | None,
+        update: models.SessionLauncherUpdate,
         session: AsyncSession | None = None,
-        **kwargs: Any,
     ) -> models.SessionLauncher:
         """Update a session launcher entry."""
         if not user.is_authenticated or user.id is None:
@@ -336,8 +341,8 @@ async def update_launcher(
             if not authorized:
                 raise errors.ForbiddenError(message="You do not have the required permissions for this operation.")
 
-            resource_class_id = kwargs.get("resource_class_id")
-            if resource_class_id is not None:
+            resource_class_id = update.resource_class_id
+            if isinstance(resource_class_id, int):
                 res = await session.scalars(
                     select(schemas.ResourceClassORM).where(schemas.ResourceClassORM.id == resource_class_id)
                 )
@@ -354,30 +359,32 @@ async def update_launcher(
                         message=f"You do not have access to resource class with id '{resource_class_id}'."
                     )
 
-            for key, value in kwargs.items():
-                # NOTE: Only some fields can be updated.
-                if key in [
-                    "name",
-                    "description",
-                    "resource_class_id",
-                ]:
-                    setattr(launcher, key, value)
-
-            env_payload = kwargs.get("environment", {})
-            await self.__update_launcher_environment(user, launcher, session, new_custom_environment, **env_payload)
+            # NOTE: Only some fields can be updated.
+            if update.name is not None:
+                launcher.name = update.name
+            if update.description is not None:
+                launcher.description = update.description
+            if isinstance(update.resource_class_id, int):
+                launcher.resource_class_id = update.resource_class_id
+            elif isinstance(update.resource_class_id, Reset):
+                launcher.resource_class_id = None
+
+            if update.environment is None:
+                return launcher.dump()
+
+            await self.__update_launcher_environment(user, launcher, session, update.environment)
             return launcher.dump()
 
     async def __update_launcher_environment(
         self,
         user: base_models.APIUser,
         launcher: schemas.SessionLauncherORM,
         session: AsyncSession,
-        new_custom_environment: models.UnsavedEnvironment | None,
-        **kwargs: Any,
+        update: models.EnvironmentUpdate | models.UnsavedEnvironment | str,
     ) -> None:
         current_env_kind = launcher.environment.environment_kind
-        match new_custom_environment, current_env_kind, kwargs:
-            case None, _, {"id": env_id, **nothing_else} if len(nothing_else) == 0:
+        match update, current_env_kind:
+            case str() as env_id, _:
                 # The environment in the launcher is set via ID, the new ID has to refer
                 # to an environment that is GLOBAL.
                 old_environment = launcher.environment
@@ -404,29 +411,11 @@ async def __update_launcher_environment(
                     # We remove the custom environment to avoid accumulating custom environments that are not associated
                     # with any launchers.
                     await session.delete(old_environment)
-            case None, models.EnvironmentKind.CUSTOM, {**rest} if (
-                rest.get("environment_kind") is None
-                or rest.get("environment_kind") == models.EnvironmentKind.CUSTOM.value
-            ):
+            case models.EnvironmentUpdate(), models.EnvironmentKind.CUSTOM:
                 # Custom environment being updated
-                for key, val in rest.items():
-                    # NOTE: Only some fields can be updated.
-                    if key in [
-                        "name",
-                        "description",
-                        "container_image",
-                        "default_url",
-                        "port",
-                        "working_directory",
-                        "mount_directory",
-                        "uid",
-                        "gid",
-                        "args",
-                        "command",
-                    ]:
-                        setattr(launcher.environment, key, val)
-            case models.UnsavedEnvironment(), models.EnvironmentKind.GLOBAL, {**nothing_else} if (
-                len(nothing_else) == 0 and new_custom_environment.environment_kind == models.EnvironmentKind.CUSTOM
+                self.__update_environment(launcher.environment, update)
+            case models.UnsavedEnvironment() as new_custom_environment, models.EnvironmentKind.GLOBAL if (
+                new_custom_environment.environment_kind == models.EnvironmentKind.CUSTOM
             ):
                 # Global environment replaced by a custom one
                 new_env = await self.__insert_environment(user, session, new_custom_environment)