Then, in that case, it could be simpler to have **one container** with **multiple processes**, and a local tool (e.g. a Prometheus exporter) on the same container collecting Prometheus metrics for all the internal processes and exposing those metrics on that single container.

---

You could create an API with a *path operation* that could trigger a request to an *external API* created by someone else (probably the same developer that would be *using* your API).

The process that happens when your API app calls the *external API* is named a "callback". Because the software that the external developer wrote sends a request to your API and then your API *calls back*, sending a request to an *external API* (that was probably created by the same developer).

   * generates a synthetic method for the body of the lambda, the actual method calls that Animal
   * Sniffer is flagging don't appear inside toImmutableSortedMultiset but rather inside that
   * synthetic method. By moving those calls to a named method, we're able to apply
   * @IgnoreJRERequirement somewhere that it will help.
   */

# OpenAPI Webhooks

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

## Webhooks steps

Then we can test that it is used.

## Reading a `.env` file

If you have many settings that possibly change a lot, maybe in different environments, it might be useful to put them on a file and then read them from it as if they were environment variables.

/**
 * A set of worker threads that are shared among a set of task queues.
 *
 * Use [INSTANCE] for a task runner that uses daemon threads. There is not currently a shared
 * instance for non-daemon threads.
 *
 * The task runner is also responsible for releasing held threads when the library is unloaded.
 * This is for the benefit of container environments that implement code unloading.
 *

/**
 * This class contains static utility methods that operate on or return objects of type {@link
 * Iterator}. Except as noted, each method has a corresponding {@link Iterable}-based method in the
 * {@link Iterables} class.
 *
 * <p><i>Performance notes:</i> Unless otherwise noted, all of the iterators produced in this class
 * are <i>lazy</i>, which means that they only advance the backing iteration when absolutely
 * necessary.
 *

      // substitute an empty ImmutableSet to the user in place of this
      if (object instanceof CartesianSet) {
        CartesianSet<?> that = (CartesianSet<?>) object;
        return this.axes.equals(that.axes);
      }
      if (object instanceof Set) {
        Set<?> that = (Set<?>) object;
        return this.size() == that.size() && this.containsAll(that);
      }

   *
   * <p><b>Note:</b> Despite what the method name suggests, if {@code elements} is an {@code
   * ImmutableSortedSet}, it may be returned instead of a copy.
   *
   * <p>This method is not type-safe, as it may be called on elements that are not mutually
   * comparable.
   *
   * <p>This method is safe to use even when {@code elements} is a synchronized or concurrent
   * collection that is currently being modified by another thread.

## Program and Process

We will talk a lot about the running "**process**", so it's useful to have clarity about what it means, and what's the difference with the word "**program**".

### What is a Program

The word **program** is commonly used to describe many things:

* The **code** that you write, the **Python files**.
* The **file** that can be **executed** by the operating system, for example: `python`, `python.exe` or `uvicorn`.