/// note | Technische Details

Wenn Sie Abhängigkeiten mit `yield` haben, wird der Exit-Code *nach* der Middleware ausgeführt.

Wenn es Hintergrundtasks gab (dies wird später im [Hintergrundtasks](background-tasks.md){.internal-link target=_blank}-Abschnitt behandelt), werden sie *nach* allen Middlewares ausgeführt.

///

## Eine Middleware erstellen { #create-a-middleware }

## Status

ACCEPTED

## Consequences

- Assign ownership of each architecture module to one team.
- Assign each source file to one architecture module.
- Align the source tree layout with this architecture.

    void interactionWithConsumerIsAsExpected() {
        // Arrange: choose a small set of known DOS codes
        List<Integer> inputs = Arrays.asList(0x00000000, 0x00050001, 0x007b0001, 0x0BADF00D);
        @SuppressWarnings("unchecked")
        BiConsumer<Integer, Integer> consumer = mock(BiConsumer.class);

        // Act: for each input, if a mapping exists, notify the consumer

 * ...
 * ThreadN: acquire(LockN) --X acquire(LockA)
 * </pre>
 *
 * <p>The implementation detects cycles by constructing a directed graph in which each lock
 * represents a node and each edge represents an acquisition ordering between two locks.
 *
 * <ul>
 *   <li>Each lock adds (and removes) itself to/from a ThreadLocal Set of acquired locks when the
 *       Thread acquires its first hold (and releases its last remaining hold).

   * value, you should always choose it explicitly.
   *
   * <p>The current implementation uses the concurrency level to create a fixed number of hashtable
   * segments, each governed by its own write lock. The segment lock is taken once for each explicit
   * write, and twice for each cache loading computation (once prior to loading the new value, and
   * once after loading completes). Much internal cache management is performed at the segment

  # NOTE: All flags are optional
  # - filtering criteria only applies for all source objects match the criteria
  # - configurable notification endpoints
  # - configurable retries for the job (each retry skips successfully previously replaced objects)
  flags:
    filter:
      newerThan: "7d10h31s" # match objects newer than this value (e.g. 7d10h31s)

You can add middleware to **FastAPI** applications.

A "middleware" is a function that works with every **request** before it is processed by any specific *path operation*. And also with every **response** before returning it.

* It takes each **request** that comes to your application.
* It can then do something to that **request** or run any needed code.
* Then it passes the **request** to be processed by the rest of the application (by some *path operation*).

client can use now `mybucket.domain.com` to directly resolve itself to the right cluster. `MINIO_PUBLIC_IPS`
points to the public IP address where each cluster might be accessible, this is unique for each cluster.

NOTE: `mybucket` only exists on one cluster either `cluster1` or `cluster2` this is random and
is decided by how `domain.com` gets resolved, if there is a round-robin DNS on `domain.com` then

    tags: set[str] = set()


@app.post("/items/", response_model=Item, summary="Create an item")
async def create_item(item: Item):
    """
    Create an item with all the information:

    - **name**: each item must have a name
    - **description**: a long description
    - **price**: required
    - **tax**: if the item doesn't have tax, you can omit this
    - **tags**: a set of unique tag strings for this item
    """

But every time we do:

```Python
Settings()
```

a new `Settings` object would be created, and at creation it would read the `.env` file again.

If the dependency function was just like:

```Python
def get_settings():
    return Settings()
```