In general, Istio does not fail on missing CRDs and prefers to treat these as if there were just zero resources for that client.
  The `NewDelayedInformer` abstracts that entirely, offering the same API as normal `kclient.Client`.
* Simple object filtering. Beyond just static filters on objects, `kclient` supports _dynamic filters_ that can change at runtime.

# Security

There are many ways to handle security, authentication and authorization.

And it normally is a complex and "difficult" topic.

In many frameworks and systems just handling security and authentication takes a big amount of effort and code (in many cases it can be 50% or more of all the code written).

This example doesn't implement the callback itself (that could be just a line of code), only the documentation part.

!!! tip
    The actual callback is just an HTTP request.

## Response with arbitrary `dict`

You can also declare a response using a plain arbitrary `dict`, declaring just the type of the keys and values, without using a Pydantic model.

This is useful if you don't know the valid field/attribute names (that would be needed for a Pydantic model) beforehand.

In this case, you can use `typing.Dict` (or just `dict` in Python 3.9 and above):

=== "Python 3.9+"

    ```Python hl_lines="6"

* Processing data:
    * For example, let's say you receive a file that must go through a slow process, you can return a response of "Accepted" (HTTP 202) and process it in the background.

## Using `BackgroundTasks`

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Just Modern Python

It's all based on standard **Python type** declarations (thanks to Pydantic). No new syntax to learn. Just standard modern Python.

But the rest of the session code is more or less the same, we just copy it.

```Python hl_lines="8-13"
{!../../../docs_src/sql_databases/sql_app/tests/test_sql_app.py!}
```

!!! tip
    You could reduce duplication in that code by putting it in a function and using it from both `database.py` and `tests/test_sql_app.py`.

    For simplicity and to focus on the specific testing code, we are just copying it.

## Create the database

            // calling the FilterReader ourselves.  We're just taking one file and turning it into another.

            // The order here is important! tokens are inserted by the transformer
            Map<String, Object> parameters = new HashMap<>();
            // NOTE: These parameter names _must_ match the setter names in ReleaseNotesTransformer

Do you want to just have a `str`? Or just a `dict`? Or a database class model instance directly? It all works the same way.

You actually don't have users that log in to your application but robots, bots, or other systems, that have just an access token? Again, it all works the same.

- Now click on the new project you just created. The URL should be `https://builds.gradle.org/admin/editProject.html?projectId=Gradle_<MyTestBranch>`.
- Click `Versioned Settings` on the left sidebar.
  - Select `Synchronization enabled` - `use settings from VCS` - `MyNewVcsRoot`(the one you just created) - `Settings format: Kotlin`, then `Apply`.