Я расскажу больше про образы контейнеров, Docker, Kubernetes и т.п. в следующей главе: [FastAPI внутри контейнеров — Docker](docker.md).

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## Предварительные шаги перед запуском { #previous-steps-before-starting }

Во многих случаях вы захотите выполнить некоторые шаги **перед запуском** приложения.

Например, запустить **миграции базы данных**.

Но чаще всего эти шаги нужно выполнять только **один раз**.

Я розповім більше про образи контейнерів, Docker, Kubernetes тощо в майбутньому розділі: [FastAPI у контейнерах - Docker](docker.md).

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## Попередні кроки перед стартом { #previous-steps-before-starting }

Є багато випадків, коли потрібно виконати деякі кроки **перед стартом** вашого застосунку.

Наприклад, ви можете захотіти запустити **міграції бази даних**.

labels: [question]
body:
  - type: markdown
    attributes:
      value: |
        Thanks for your interest in FastAPI! 🚀

        Please follow these instructions, fill every question, and do every step. 🙏

        I'm asking this because answering questions and solving problems in GitHub is what consumes most of the time.

* Security - HTTPS
* Running on startup
* Restarts
* Replication (the number of processes running)
* Memory
* Previous steps before starting

 * an existing external tool is required.
 *
 * See https://stackoverflow.com/questions/61929216/how-to-log-tlsv1-3-keys-in-jsse-for-wireshark-to-decode-traffic
 *
 * Steps to run in your own code
 *
 * 1. In your main method `WireSharkListenerFactory.register()`
 * 2. Create Listener factory `val eventListenerFactory = WireSharkListenerFactory(

따라서, 아래는 모두 상이한 출처입니다:

* `http://localhost`
* `https://localhost`
* `http://localhost:8080`

모두 `localhost`에 있더라도, 서로 다른 프로토콜이나 포트를 사용하므로 서로 다른 "출처"입니다.

## 단계 { #steps }

그러면 브라우저에서 `http://localhost:8080`으로 실행되는 프론트엔드가 있고, 그 JavaScript가 `http://localhost`에서 실행되는 백엔드와 통신하려고 한다고 해봅시다(포트를 명시하지 않았기 때문에, 브라우저는 기본 포트 `80`을 가정합니다).

 4. If it's a new route, it connects by building either a direct socket connection, a TLS tunnel (for HTTPS over an HTTP proxy), or a direct TLS connection. It does TLS handshakes as necessary. This step may be retried for tunnel challenges and TLS handshake failures.
 5. It sends the HTTP request and reads the response.

### 1. Fetch the root identity

As the initial step, fetch the private key and certificate of the root identity:

```sh
curl -sSL --tlsv1.2 \
     -O 'https://raw.githubusercontent.com/minio/kes/master/root.key' \

We’ve included deprecated APIs in OkHttp 4.0 because they make migration easy. We will remove them
in a future release! If you’re skipping releases, it’ll be much easier if you upgrade to OkHttp 4.0
as an intermediate step.

#### Vars and Vals

Java doesn’t have language support for properties so developers make do with getters and setters.
Kotlin does have properties and we take advantage of them in OkHttp.

     * #COMPLETED}, {@link #CANCELLED}, or {@link #INTERRUPTED}
     *
     * <p>To avoid races between threads doing release and acquire, we transition to the final state
     * in two steps. One thread will successfully CAS from RUNNING to COMPLETING, that thread will
     * then set the result of the computation, and only then transition to COMPLETED, CANCELLED, or
     * INTERRUPTED.
     *