Las variables de entorno pueden ser útiles para manejar **configuraciones** de aplicaciones, como parte de la **instalación** de Python, etc.

## Crear y Usar Variables de Entorno { #create-and-use-env-vars }

Puedes **crear** y usar variables de entorno en la **shell (terminal)**, sin necesidad de Python:

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console

            `/openapi.json`.

            Read more about it in the
            [FastAPI docs for Conditional OpenAPI](https://fastapi.tiangolo.com/how-to/conditional-openapi/#conditional-openapi-from-settings-and-env-vars)
            """
        ),
    ],
    title: Annotated[
        str,
        Doc(
            """
            The HTML `<title>` content, normally shown in the browser tab.

	@echo "Building minio binary to './minio'"
	@CGO_ENABLED=0 GOOS=$(GOOS) GOARCH=$(GOARCH) go build -tags kqueue -trimpath --ldflags "$(LDFLAGS)" -o $(PWD)/minio 1>/dev/null

hotfix-vars:
	$(eval LDFLAGS := $(shell MINIO_RELEASE="RELEASE" MINIO_HOTFIX="hotfix.$(shell git rev-parse --short HEAD)" go run buildscripts/gen-ldflags.go $(shell git describe --tags --abbrev=0 | \

- 实现并使用成熟的密码学工具，比如 pwdlib 和 JWT 令牌等。
- 在需要的地方使用 OAuth2 作用域添加更细粒度的权限控制。
- ...等。

尽管如此，你可能确实有非常特定的用例，需要在某些环境（例如生产环境）禁用 API 文档，或根据环境变量的配置来决定。

## 基于设置和环境变量的条件式 OpenAPI { #conditional-openapi-from-settings-and-env-vars }

你可以很容易地使用相同的 Pydantic 设置来配置生成的 OpenAPI 和文档 UI。

例如：

{* ../../docs_src/conditional_openapi/tutorial001_py310.py hl[6,11] *}

这里我们声明了设置项 `openapi_url`，其默认值同样是 `"/openapi.json"`。

然后在创建 `FastAPI` 应用时使用它。

Variáveis de ambiente podem ser úteis para lidar com **configurações** do aplicativo, como parte da **instalação** do Python, etc.

## Criar e Usar Variáveis de Ambiente { #create-and-use-env-vars }

Você pode **criar** e usar variáveis de ambiente no **shell (terminal)**, sem precisar do Python:

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console

          - "5557:5557"
        env:
          DEX_LDAP_SERVER: "openldap:389"
          DEX_ISSUER: "http://127.0.0.1:5557/dex"
          DEX_WEB_HTTP: "0.0.0.0:5557"

    strategy:
      # When ldap, etcd or openid vars are empty below, those external servers
      # are turned off - i.e. if ldap="", then ldap server is not enabled for
      # the tests.
      matrix:
        go-version: [1.24.x]
        ldap: ["", "localhost:389"]

						dbName = f.DBName
					}
				}

				if tx.Statement.Distinct {
					expr = clause.Expr{SQL: "COUNT(DISTINCT(?))", Vars: []interface{}{clause.Column{Name: dbName}}}
				} else if dbName != "*" {
					expr = clause.Expr{SQL: "COUNT(?)", Vars: []interface{}{clause.Column{Name: dbName}}}
				}
			}
		}

		tx.Statement.AddClause(clause.Select{Expression: expr})
	}

   * the table lacks a mapping for a given row and column, the corresponding array element is null.
   *
   * <p>Subsequent table changes will not modify the array, and vice versa.
   *
   * @param valueClass class of values stored in the returned array
   */
  @GwtIncompatible // reflection
  public @Nullable V[][] toArray(Class<V> valueClass) {

	body := `{"recursive": false, "dryRun": true, "remove": false, "scanMode": 0}`

	// Test all combinations!
	for pIdx, params := range qParamsArr {
		for vIdx, vars := range varsArr {
			_, err := extractHealInitParams(vars, params, bytes.NewReader([]byte(body)))
			isErrCase := false
			if pIdx < 4 || vIdx < 1 {
				isErrCase = true
			}

			if err != ErrNone && !isErrCase {

///

### Pydantic v1 and v2 on the same app { #pydantic-v1-and-v2-on-the-same-app }

It's **not supported** by Pydantic to have a model of Pydantic v2 with its own fields defined as Pydantic v1 models or vice versa.

```mermaid
graph TB
    subgraph "❌ Not Supported"
        direction TB
        subgraph V2["Pydantic v2 Model"]
            V1Field["Pydantic v1 Model"]
        end
        subgraph V1["Pydantic v1 Model"]