* limitations under the License.
 */

package util

import common.Arch
import common.BuildToolBuildJvm
import common.JvmVendor
import common.JvmVersion
import common.KillProcessMode.KILL_LEAKED_PROCESSES_FROM_PREVIOUS_BUILDS
import common.KillProcessMode.KILL_PROCESSES_STARTED_BY_GRADLE
import common.Os
import common.applyDefaultSettings
import common.buildToolGradleParameters
import common.checkCleanM2AndAndroidUserHome

## Previous Steps Before Starting

There are many cases where you want to perform some steps **before starting** your application.

For example, you might want to run **database migrations**.

But in most cases, you will want to perform these steps only **once**.

So, you will want to have a **single process** to perform those **previous steps**, before starting the application.

package configurations

import common.Arch
import common.BuildToolBuildJvm
import common.Jvm
import common.KillProcessMode.KILL_ALL_GRADLE_PROCESSES
import common.KillProcessMode.KILL_LEAKED_PROCESSES_FROM_PREVIOUS_BUILDS
import common.KillProcessMode.KILL_PROCESSES_STARTED_BY_GRADLE
import common.Os
import common.VersionedSettingsBranch
import common.applyDefaultSettings
import common.buildToolGradleParameters

    }

    @Test
    fun `can apply defaults to configurations`() {
        applyDefaults(buildModel, buildType, "myTask")

        assertEquals(
            listOf(
                "KILL_LEAKED_PROCESSES_FROM_PREVIOUS_BUILDS",
                "GRADLE_RUNNER",
                "KILL_PROCESSES_STARTED_BY_GRADLE",
                "CHECK_CLEAN_M2_ANDROID_USER_HOME"
            ),
            steps.items.map(BuildStep::name)
        )

## Official Docker Image with Gunicorn - Uvicorn

There is an official Docker image that includes Gunicorn running with Uvicorn workers, as detailed in a previous chapter: [Server Workers - Gunicorn with Uvicorn](server-workers.md){.internal-link target=_blank}.

But before that, handling asynchronous code was quite more complex and difficult.

In previous versions of Python, you could have used threads or <a href="https://www.gevent.org/" class="external-link" target="_blank">Gevent</a>. But the code is way more complex to understand, debug, and think about.

# Server Workers - Gunicorn with Uvicorn

Let's check back those deployment concepts from before:

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

Up to this point, with all the tutorials in the docs, you have probably been running a **server program** like Uvicorn, running a **single process**.

# Classes as Dependencies

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example

In the previous example, we were returning a `dict` from our dependency ("dependable"):

=== "Python 3.10+"

    ```Python hl_lines="9"
    {!> ../../../docs_src/dependencies/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="11"

          color: '0000FF'
  {% endfor %}

# To simplify the automations section, some calculations are placed under unique YAML keys defined here.
# Read the "|" not as "or", but as a "pipe", taking the output of the previous command and passing it to the next command.

# TODO: It would be very nice to avoid having this list somehow, but it needs to be defined in YAML and not in JS for the looping template to work

But at some point, there was no other option than creating something that provided all these features, taking the best ideas from previous tools, and combining them in the best way possible, using language features that weren't even available before (Python 3.6+ type hints).

## Previous tools

### <a href="https://www.djangoproject.com/" class="external-link" target="_blank">Django</a>