///

For example, this custom validator checks that the item ID starts with `isbn-` for an <abbr title="ISBN means International Standard Book Number">ISBN</abbr> book number or with `imdb-` for an <abbr title="IMDB (Internet Movie Database) is a website with information about movies">IMDB</abbr> movie URL ID:

{* ../../docs_src/query_params_str_validations/tutorial015_an_py310.py hl[5,16:19,24] *}

/// info

To achieve this, you will normally have a **separate program** that would make sure your application is run on startup. And in many cases, it would also make sure other components or applications are also run, for example, a database.

### Example Tools to Run at Startup { #example-tools-to-run-at-startup }

Some examples of the tools that can do this job are:

* Docker
* Kubernetes
* Docker Compose
* Docker in Swarm Mode

You can only use `await` inside of functions created with `async def`.

///

---

If you are using a third party library that communicates with something (a database, an API, the file system, etc.) and doesn't have support for using `await`, (this is currently the case for most database libraries), then declare your *path operation functions* as normally, with just `def`, like:

```Python hl_lines="2"
@app.get('/')
def results():

    * Mümkün olduğu kadar modüler yapılmıştır, bu nedenle kutudan çıktığı gibi çalışır, ancak Vue CLI ile yeniden oluşturabilir veya ihtiyaç duyduğunuz şekilde oluşturabilir ve istediğinizi yeniden kullanabilirsiniz.
* **PGAdmin** PostgreSQL database admin tool'u, PHPMyAdmin ve MySQL ile kolayca değiştirilebilir.
* **Flower** ile Celery job'larını monitörleme.

package logger

import (
	"database/sql/driver"
	"fmt"
	"reflect"
	"regexp"
	"strconv"
	"strings"
	"time"
	"unicode"

	"gorm.io/gorm/utils"
)

const (
	tmFmtWithMS = "2006-01-02 15:04:05.999"
	tmFmtZero   = "0000-00-00 00:00:00"
	nullStr     = "NULL"
)

func isPrintable(s string) bool {
	for _, r := range s {
		if !unicode.IsPrint(r) {
			return false
		}
	}
	return true
}

That way, in many cases you can learn about containers and Docker and reuse that knowledge with many different tools and components.

In many cases your application could need some external settings or configurations, for example secret keys, database credentials, credentials for email services, etc.

Most of these settings are variable (can change), like database URLs. And many could be sensitive, like secrets.

For this reason it's common to provide them in environment variables that are read by the application.

/// tip

 * </ul>
 *
 * <h3>Example</h3>
 *
 * <p>Here is an example that accepts a list from a database call, filters it based on a predicate,
 * transforms it by invoking {@code toString()} on each element, and returns the first 10 elements
 * as a {@code List}:
 *
 * {@snippet :
 * ImmutableList<String> results =
 *     FluentIterable.from(database.getClientList())
 *         .filter(Client::isActiveInLastMonth)

 * </ul>
 *
 * <h3>Example</h3>
 *
 * <p>Here is an example that accepts a list from a database call, filters it based on a predicate,
 * transforms it by invoking {@code toString()} on each element, and returns the first 10 elements
 * as a {@code List}:
 *
 * {@snippet :
 * ImmutableList<String> results =
 *     FluentIterable.from(database.getClientList())
 *         .filter(Client::isActiveInLastMonth)

		t.Fatalf("Should find saved record")
	}
}

func TestTransactionOnClosedConn(t *testing.T) {
	DB, err := OpenTestConnection(&gorm.Config{})
	if err != nil {
		t.Fatalf("failed to connect database, got error %v", err)
	}
	rawDB, _ := DB.DB()
	rawDB.Close()

	if err := DB.Transaction(func(tx *gorm.DB) error {
		return nil
	}); err == nil {