## ASGI Servers { #asgi-servers }

Let's go a little deeper into the details.

FastAPI uses a standard for building Python web frameworks and servers called <abbr title="Asynchronous Server Gateway Interface">ASGI</abbr>. FastAPI is an ASGI web framework.

        objAttr.encode(mockNdrBuffer);

        verify(mockNdrBuffer).align(4);
        verify(mockNdrBuffer).enc_ndr_long(objAttr.length);
        verify(mockNdrBuffer, times(3)).enc_ndr_referent(null, 1); // Called 3 times for null root_directory, object_name, and security_quality_of_service
        verify(mockNdrBuffer).enc_ndr_long(objAttr.attributes);
        verify(mockNdrBuffer).enc_ndr_long(objAttr.security_descriptor);

    if (length == size()) {
      return this;
    } else if (length == 0) {
      return of();
    } else {
      return subListUnchecked(fromIndex, toIndex);
    }
  }

  /**
   * Called by the default implementation of {@link #subList} when {@code toIndex - fromIndex > 1},
   * after index validation has already been performed.
   */
  ImmutableList<E> subListUnchecked(int fromIndex, int toIndex) {

   * safe to do so. The exact circumstances under which a copy will or will not be performed are
   * undocumented and subject to change.
   *
   * <p>This method is not type-safe, as it may be called on elements that are not mutually
   * comparable.
   *
   * @throws ClassCastException if the elements are not mutually comparable
   * @throws NullPointerException if any of {@code elements} is null
   */

        return (int) requestCounters.size();
    }

    /**
     * Clean up expired entries.
     * Note: Guava Cache handles expiration automatically, but this method
     * can be called to force immediate cleanup.
     */
    public void cleanup() {
        requestCounters.cleanUp();
        blockedIps.cleanUp();
        if (logger.isDebugEnabled()) {

      } else {
        return EventListener.NONE;
      }
    }
  };

  ...
}
```

### Events with Failures

When an operation fails, a failure method is called. This is `connectFailed()` for failures while building a connection to the server, and `callFailed()` when the HTTP call fails permanently. When a failure happens it is possible that a `start` event won’t have a corresponding `end` event.

        byte[] buffer = new byte[8];
        int encoded = spy.encode(buffer, 0);
        int decoded = spy.decode(buffer, 0, 8);
        String str = spy.toString();

        // Verify all methods were called except toString (Mockito limitation)
        verify(spy).getFileInformationLevel();
        verify(spy).size();
        verify(spy).encode(buffer, 0);
        verify(spy).decode(buffer, 0, 8);

[Download the latest release](https://prometheus.io/download) of Prometheus for your platform, then extract it

```sh
tar xvfz prometheus-*.tar.gz
cd prometheus-*
```

Prometheus server is a single binary called `prometheus` (or `prometheus.exe` on Microsoft Windows). Run the binary and pass `--help` flag to see available options

```sh
./prometheus --help
usage: prometheus [<flags>]

The Prometheus monitoring server

///

The `oauth2_scheme` variable is an instance of `OAuth2PasswordBearer`, but it is also a "callable".

It could be called as:

```Python
oauth2_scheme(some, parameters)
```

So, it can be used with `Depends`.

### Use it { #use-it }

Now you can pass that `oauth2_scheme` in a dependency with `Depends`.

    /** The filter chain used to process queries */
    protected FilterChain filterChain;

    /**
     * Initializes the query parser by creating the filter chain.
     * This method is called automatically after construction.
     */
    @PostConstruct
    public void init() {
        createFilterChain();
    }

    /**
     * Parses the given query string and returns a Lucene Query object.