使用Waitress部署Django/PostgreSQL到Heroku遇R10端口绑定错误

我正尝试用Waitress将Django/PostgreSQL项目部署到Heroku（多年前用Gunicorn成功部署过一次），最终遇到错误：

Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch

完整错误日志：

2025-04-09T07:09:48.289599+00:00 heroku[web.1]: State changed from crashed to starting
2025-04-09T07:09:52.235046+00:00 heroku[web.1]: Starting process with command `waitress-serve project.wsgi:application`
2025-04-09T07:09:52.781389+00:00 app[web.1]: Python buildpack: Detected 512 MB available memory and 8 CPU cores.
2025-04-09T07:09:52.781847+00:00 app[web.1]: Python buildpack: Defaulting WEB_CONCURRENCY to 2 based on the available memory.
2025-04-09T07:09:53.244456+00:00 app[web.1]: INFO:waitress:Serving on http://0.0.0.0:8080
2025-04-09T07:10:52.357945+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2025-04-09T07:10:52.370446+00:00 heroku[web.1]: Stopping process with SIGKILL
2025-04-09T07:10:52.421789+00:00 heroku[web.1]: Process exited with status 137
2025-04-09T07:10:52.445044+00:00 heroku[web.1]: State changed from starting to crashed"

我最初以为是PORT定义问题，但从Procfile中移除相关设置后，Heroku似乎已自动指定本地PORT，该问题仍未解决。想知道导致“failed to bind to $PORT”的可能原因，是否与DATABASE_URL有关？我正在使用Heroku的SSL，但相关设置尚未理清。

附上我的配置文件：

Procfile #

web: waitress-serve project.wsgi:application

.env #

WEB_CONCURRENCY=3
PORT=PORT
SECRET_KEY=[text-of-secret-key]

base.py #

import os
import django_on_heroku
import environ
from environ import Env
from dotenv import load_dotenv
import dj_database_url

load_dotenv()

env = Env()

BASE_DIR = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

environ.Env.read_env(os.path.join(BASE_DIR, '.env'))

SECRET_KEY = env('SECRET_KEY')
PORT = env('PORT')

SECURE_HSTS_SECONDS = 3600
SECURE_SSL_REDIRECT = False
SESSION_COOKIE_SECURE = True
CSRF_COOKIE_SECURE = True

DEBUG = True

ALLOWED_HOSTS = ['.herokuapp.com/', 'localhost']

INSTALLED_APPS = [
    'cgp.apps.CgpConfig',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'django.contrib.humanize',
    'ajax_datatable',
    'whitenoise.runserver_nostatic',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'whitenoise.middleware.WhiteNoiseMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'project.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR, "templates")],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
                'django.template.context_processors.request',
            ],
        },
    },
]

WSGI_APPLICATION = 'project.wsgi.application'


IS_HEROKU_APP = "DYNO" in os.environ and "CI" not in os.environ

if IS_HEROKU_APP:
    DATABASES = {}
    DATABASES['default'] = dj_database_url.config(conn_max_age=600)
else:
    DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'NAME': 'cgp',
            'USER': 'postgres',
            'PASSWORD': 'postgres',
            'HOST': 'localhost',
            'PORT': '5432',
        }
    }

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_TZ = True


STATIC_ROOT = os.path.join(BASE_DIR, 'static') ##same as beta

STATIC_URL = '/static/' ##same as beta

STATICFILES_STORAGE = 'whitenoise.storage.CompressedManifestStaticFilesStorage' ##same as beta


STATICFILES_DIRS = [
    os.path.join(BASE_DIR, 'cgp/static'),
]

DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

django_on_heroku.settings(locals())

（不确定DATABASES的条件定义是否必要，但移除Heroku条件后仍出现相同错误。）

heroku.py #

import environ
#import dj_database_url

# If using in your own project, update the project namespace below
from project.settings.base import *

env = environ.Env(
    # set casting, default value
    DEBUG=(bool, True)
)

# False if not in os.environ
DEBUG = env('DEBUG')

# Raises django's ImproperlyConfigured exception if SECRET_KEY not in os.environ
SECRET_KEY = env('SECRET_KEY')

ALLOWED_HOSTS = env.list('ALLOWED_HOSTS')

# Parse database connection url strings like psql://user:pass@127.0.0.1:8458/db
DATABASES = {
    # read os.environ['DATABASE_URL'] and raises ImproperlyConfigured exception if not found
    'default': env.db(),
}

requirements.txt #

asgiref==3.7.2
dj-database-url==2.3.0
Django==4.2.5
django-ajax-datatable==4.5.0
django-environ==0.12.0
django-heroku==0.3.1
django-on-heroku==1.1.2
gunicorn==23.0.0
packaging==24.2
psycopg2==2.9.7
psycopg2-binary==2.9.10
python-dotenv==1.0.1
sqlparse==0.4.4
typing_extensions==4.12.2
tzdata==2023.3
waitress==3.0.2
whitenoise==6.9.0

从错误日志能明显看到核心问题：Waitress绑定了固定端口8080，但Heroku要求应用必须绑定到环境变量$PORT指定的端口，而不是硬编码的端口。

1. 修正Procfile，让Waitress读取Heroku的$PORT #

当前Procfile没有指定端口参数，Waitress默认用8080，不符合Heroku要求。修改Procfile，明确让Waitress绑定到$PORT：

web: waitress-serve --port=$PORT project.wsgi:application

2. 清理不必要的PORT配置 #

• 从.env中删除PORT=PORT这一行，Heroku会自动设置这个环境变量，本地开发时可单独设置或使用Waitress默认端口。
• 从base.py中删除PORT = env('PORT')这一行，Django本身不需要该变量，端口由WSGI服务器（Waitress）处理。

3. 数据库配置检查（当前错误与数据库无关，但需确保配置正确） #

日志中无数据库连接失败提示，所以当前R10错误和DATABASE_URL无关，但可优化配置：

• 保留IS_HEROKU_APP的条件判断合理，能区分本地和生产环境。
• 确保Heroku上已添加PostgreSQL插件，且DATABASE_URL环境变量正确设置（可通过heroku config:get DATABASE_URL命令查看）。

4. SSL配置调整（可选，避免后续问题） #

当前SECURE_SSL_REDIRECT=False，在Heroku建议开启：

if IS_HEROKU_APP:
    SECURE_SSL_REDIRECT = True

同时将ALLOWED_HOSTS里的.herokuapp.com/改为'.herokuapp.com'，避免主机匹配失败。

5. 重新部署验证 #

修改完成后，重新提交代码并部署：

git add .
git commit -m "Fix Waitress port binding for Heroku"
git push heroku main

部署后查看日志，若看到类似INFO:waitress:Serving on http://0.0.0.0:xxxx（xxxx为Heroku分配的随机端口），说明端口绑定成功，R10错误应会消失。

内容的提问来源于stack exchange，提问作者relp lamfred