This code is something you can actually use in your application, save the password hashes in your database, etc.

We are going to start from where we left in the previous chapter and increment it.

## About JWT

JWT means "JSON Web Tokens".

It's a standard to codify a JSON object in a long dense string without spaces. It looks like this:

```

* Upgrade to etcd client 3.3.17 to fix bug where etcd client does not parse IPv6 addresses correctly when members are joining, and to fix bug where failover on multi-member etcd cluster fails certificate check on DNS mismatch ([#83801](https://github.com/kubernetes/kubernetes/pull/83801), [@jpbetz](https://github.com/jpbetz))

 * follows:
 *
 * <ul>
 *   <li>"{@code [group }<i>i</i>{@code , item }<i>j</i>{@code ]}" refers to the
 *       <i>j</i><sup>th</sup> item in the <i>i</i><sup>th</sup> equality group, where both equality
 *       groups and the items within equality groups are numbered starting from 1. When either a
 *       constructor argument or an equal object is provided, that becomes group 1.
 * </ul>
 *

We accept Pull Requests via GitHub. The [developer mailing list][dev-ml-list] is the
main channel of communication for contributors.  
There are some guidelines which will make applying PRs easier for us:
+ Create a topic branch from where you want to base your work (this is usually the master branch).
  Push your changes to a topic branch in your fork of the repository.
+ Make commits of logical units.

             * return which would render the timeout effectively useless.
             */
            doConnect();
        } catch( Exception ex ) {
            ex0 = ex; // Defer to below where we're locked
            return;
        } finally {
            synchronized (run_thread) {
                if (run_thread != thread) {
                    /* Thread no longer the one setup for this transport --

// httpListener - HTTP listener capable of handling multiple server addresses.
type httpListener struct {
	opts        TCPOptions
	listeners   []net.Listener    // underlying TCP listeners.
	acceptCh    chan acceptResult // channel where all TCP listeners write accepted connection.
	ctx         context.Context
	ctxCanceler context.CancelFunc
}

Author: Harshavardhana <******@****.***>
Date:   Sat Jun 15 11:27:17 2019 -0700

    [security] Match ${aws:username} exactly instead of prefix match (#7791)

    This PR fixes a security issue where an IAM user based
    on his policy is granted more privileges than restricted
    by the users IAM policy.

    This is due to an issue of prefix based Matcher() function

 * **Step down considerately**: Members of every project come and go. When somebody leaves or
   disengages from the project, they should make it known and take the proper steps to ensure that
   others can pick up where they left off.

This code is not exhaustive or complete. It serves to distill our common understanding of a
collaborative, shared environment, and goals. We expect it to be followed in spirit as much as in
the letter.

  // is returned in the status.audiences field to ensure that the TokenReview
  // server is audience aware. If a TokenReview returns an empty
  // status.audience field where status.authenticated is "true", the token is
  // valid against the audience of the Kubernetes API server.
  // +optional
  repeated string audiences = 4;

  // Error indicates that the token couldn't be checked

COPY ./app /code/app

# (6)!
CMD ["fastapi", "run", "app/main.py", "--port", "80"]
```

1. Start from the official Python base image.

2. Set the current working directory to `/code`.

    This is where we'll put the `requirements.txt` file and the `app` directory.

3. Copy the file with the requirements to the `/code` directory.

    Copy **only** the file with the requirements first, not the rest of the code.