# Security Tools

When you need to declare dependencies with OAuth2 scopes you use `Security()`.

But you still need to define what is the dependable, the callable that you pass as a parameter to `Depends()` or `Security()`.

There are multiple tools that you can use to create those dependables, and they get integrated into OpenAPI so they are shown in the automatic docs UI, they can be used by automatically generated clients and SDKs, etc.

{* ../../docs_src/dependencies/tutorial011_an_py310.py hl[12] *}

In this case, this `__call__` is what **FastAPI** will use to check for additional parameters and sub-dependencies, and this is what will be called to pass a value to the parameter in your *path operation function* later.

## Parameterize the instance { #parameterize-the-instance }

from fastapi import FastAPI
from fastapi.testclient import TestClient
from inline_snapshot import snapshot

app = FastAPI()


@app.get("/a/{id}")
async def a(id):
    pass  # pragma: no cover


client = TestClient(app)


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == snapshot(
        {

from fastapi import FastAPI
from fastapi.testclient import TestClient
from inline_snapshot import snapshot
from pydantic import BaseModel

app = FastAPI()


class Model(BaseModel):
    pass


class Model2(BaseModel):
    a: Model


class Model3(BaseModel):
    c: Model
    d: Model2


@app.get("/", response_model=Model3)
def f():
    return {"c": {}, "d": {"a": {}}}


client = TestClient(app)

logging.setLevel(Level.BASIC);
OkHttpClient client = new OkHttpClient.Builder()
  .addInterceptor(logging)
  .build();
```

You can change the log level at any time by calling `setLevel()`.

To log to a custom location, pass a `Logger` instance to the constructor.
```java
HttpLoggingInterceptor logging = new HttpLoggingInterceptor(new Logger() {
  @Override public void log(String message) {
    Timber.tag("OkHttp").d(message);
  }
});
```

    initiates CI/CD tests.
-   We can't move forward if these tests fail.
-   In such situations, we may request you to make further changes to your PR
    for the tests to pass.
-   Once the tests pass, we now bring all the code into the internal code base,
    using a job called "copybara".

**5. Copy to Google Internal codebase and run internal CI**

{* ../../docs_src/background_tasks/tutorial001_py310.py hl[1,13] *}

**FastAPI** will create the object of type `BackgroundTasks` for you and pass it as that parameter.

## Create a task function { #create-a-task-function }

Create a function to be run as the background task.

It is just a standard function that can receive parameters.

```yaml
# This is a sample TOML code block
title = "TOML Example"  # Title of the document
```

And more text

```console
// Use the command "live" and pass the language code as a CLI argument
$ python ./scripts/docs.py live es

<span style="color: green;">[INFO]</span> Serving on http://127.0.0.1:8008
<span style="color: green;">[INFO]</span> Start watching changes

app = FastAPI()


async def user_exists(user_id: int):
    return True


@app.get("/users/{user_id}", dependencies=[Depends(user_exists)])
async def read_users(user_id: int):
    pass


client = TestClient(app)


def test_read_users():
    response = client.get("/users/42")
    assert response.status_code == 200, response.text


def test_openapi_schema():

@app.get("/http-exception")
def route_with_http_exception():
    raise HTTPException(status_code=400)


@app.get("/request-validation/{param}/")
def route_with_request_validation_exception(param: int):
    pass  # pragma: no cover


@app.get("/server-error")
def route_with_server_error():
    raise RuntimeError("Oops!")


def test_override_http_exception():
    response = client.get("/http-exception")