*/
    public static void assertArgumentArrayIndex(final String argName, final int argValue, final int arraySize) {
        if (argValue < 0) {
            throw new ClIllegalArgumentException(argName, "ECL0014", asArray(argName));
        }
        if (argValue >= arraySize) {
            throw new ClIllegalArgumentException(argName, "ECL0015", asArray(argName, arraySize));
        }
    }

    /**

FESS_JAVA_OPTS="$FESS_JAVA_OPTS -XX:+DisableExplicitGC"

# Ensure UTF-8 encoding by default (e.g. filenames)
FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Dfile.encoding=UTF-8"

# Application Configuration
if [ "x$APP_NAME" = "x" ]; then
  APP_NAME=fess
fi
if [ "x$SEARCH_ENGINE_HOME" = "x" ]; then
  SEARCH_ENGINE_HOME=$FESS_HOME/es
fi
if [ "x$FESS_TEMP_PATH" = "x" ]; then
  FESS_TEMP_PATH=$FESS_HOME/temp
fi

from fastapi import FastAPI

from .config import settings

app = FastAPI()


@app.get("/info")
async def info():
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

from fastapi import FastAPI
from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    app_name: str = "Awesome API"
    admin_email: str
    items_per_user: int = 50


settings = Settings()
app = FastAPI()


@app.get("/info")
async def info():
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

app = FastAPI()


@lru_cache
def get_settings():
    return config.Settings()


@app.get("/info")
async def info(settings: config.Settings = Depends(get_settings)):
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

@lru_cache
def get_settings():
    return config.Settings()


@app.get("/info")
async def info(settings: Annotated[config.Settings, Depends(get_settings)]):
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Dfile.encoding=UTF-8

REM Application Configuration
set APP_NAME=fess
set SEARCH_ENGINE_HOME=%FESS_HOME%/es

if NOT "%FESS_USE_GC_LOGGING%" == "" set FESS_JAVA_OPTS=%FESS_JAVA_OPTS% -Xlog:gc*,gc+age=trace,safepoint:file=%FESS_HOME%/logs/gc-%APP_NAME%.log:utctime,pid,tags:filecount=5,filesize=64m

set FESS_CLASSPATH=%FESS_HOME%\lib\classes

     * @param args
     *            Array of arguments
     */
    public ClIllegalArgumentException(final String argName, final String messageCode, final Object[] args) {
        this(argName, messageCode, args, null);
    }

    /**
     * Creates a {@link ClIllegalArgumentException}.
     *
     * @param argName
     *            Name of the argument
     * @param messageCode
     *            Message code
     * @param args

Então, quando você cria uma instância dessa classe `Settings` (neste caso, no objeto `settings`), o Pydantic vai ler as variáveis de ambiente sem diferenciar maiúsculas de minúsculas; assim, uma variável em maiúsculas `APP_NAME` ainda será lida para o atributo `app_name`.

Em seguida, ele converterá e validará os dados. Assim, quando você usar esse objeto `settings`, terá dados dos tipos que declarou (por exemplo, `items_per_user` será um `int`).

///

Затем, когда вы создаете экземпляр этого класса `Settings` (в нашем случае объект `settings`), Pydantic прочитает переменные окружения регистронезависимо, то есть переменная в верхнем регистре `APP_NAME` будет прочитана для атрибута `app_name`.

Далее он преобразует и провалидирует данные. Поэтому при использовании объекта `settings` вы получите данные тех типов, которые объявили (например, `items_per_user` будет `int`).