即使已安装psycopg2，在heroku中进行部署时也会出现ModuleNotFoundError psycopg2

Question

我将网站从sqlite3迁移到了postgresql。我在heroku中部署网站，但是在执行命令时出现此错误 push heroku master

-----> Python app detected
 !     Python has released a security update! Please consider upgrading to python-3.7.3
       Learn More: https://devcenter.heroku.com/articles/python-runtimes
-----> Installing python-3.7.2
-----> Installing pip
-----> Installing dependencies with Pipenv 2018.5.18…
       Installing dependencies from Pipfile…
-----> Installing SQLite3
-----> $ python manage.py collectstatic --noinput
       Traceback (most recent call last):
         File "/app/.heroku/python/lib/python3.7/site-packages/django/db/backends/postgresql/base.py", line 20, in <module>
           import psycopg2 as Database
       ModuleNotFoundError: No module named 'psycopg2'
       During handling of the above exception, another exception occurred:
       Traceback (most recent call last):
         File "manage.py", line 10, in <module>
           execute_from_command_line(sys.argv)
         File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
           utility.execute()
         File "/app/.heroku/python/lib/python3.7/site-packages/django/core/management/__init__.py", line 357, in execute
           django.setup()
         File "/app/.heroku/python/lib/python3.7/site-packages/django/__init__.py", line 24, in setup
           apps.populate(settings.INSTALLED_APPS)
         File "/app/.heroku/python/lib/python3.7/site-packages/django/apps/registry.py", line 114, in populate
           app_config.import_models()
         File "/app/.heroku/python/lib/python3.7/site-packages/django/apps/config.py", line 211, in import_models
           self.models_module = import_module(models_module_name)
         File "/app/.heroku/python/lib/python3.7/importlib/__init__.py", line 127, in import_module
           return _bootstrap._gcd_import(name[level:], package, level)
         File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
         File "<frozen importlib._bootstrap>", line 983, in _find_and_load
         File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
         File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
         File "<frozen importlib._bootstrap_external>", line 728, in exec_module
         File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
         File "/tmp/build_bda0f9a0e468e1cd92eba305080085ba/home/models.py", line 3, in <module>
           from wagtail.core.models import Page
         File "/app/.heroku/python/lib/python3.7/site-packages/wagtail/core/models.py", line 8, in <module>
           from django.contrib.auth.models import Group, Permission
         File "/app/.heroku/python/lib/python3.7/site-packages/django/contrib/auth/models.py", line 2, in <module>
           from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
         File "/app/.heroku/python/lib/python3.7/site-packages/django/contrib/auth/base_user.py", line 47, in <module>
           class AbstractBaseUser(models.Model):
         File "/app/.heroku/python/lib/python3.7/site-packages/django/db/models/base.py", line 117, in __new__
           new_class.add_to_class('_meta', Options(meta, app_label))
         File "/app/.heroku/python/lib/python3.7/site-packages/django/db/models/base.py", line 321, in add_to_class
           value.contribute_to_class(cls, name)
         File "/app/.heroku/python/lib/python3.7/site-packages/django/db/models/options.py", line 204, in contribute_to_class
           self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
         File "/app/.heroku/python/lib/python3.7/site-packages/django/db/__init__.py", line 28, in __getattr__
           return getattr(connections[DEFAULT_DB_ALIAS], item)
         File "/app/.heroku/python/lib/python3.7/site-packages/django/db/utils.py", line 201, in __getitem__
           backend = load_backend(db['ENGINE'])
         File "/app/.heroku/python/lib/python3.7/site-packages/django/db/utils.py", line 110, in load_backend
           return import_module('%s.base' % backend_name)
         File "/app/.heroku/python/lib/python3.7/importlib/__init__.py", line 127, in import_module
           return _bootstrap._gcd_import(name[level:], package, level)
         File "/app/.heroku/python/lib/python3.7/site-packages/django/db/backends/postgresql/base.py", line 24, in <module>
           raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
       django.core.exceptions.ImproperlyConfigured: Error loading psycopg2 module: No module named 'psycopg2'
 !     Error while running '$ python manage.py collectstatic --noinput'.
       See traceback above for details.
       You may need to update application code to resolve this error.
       Or, you can disable collectstatic for this application:
          $ heroku config:set DISABLE_COLLECTSTATIC=1
       https://devcenter.heroku.com/articles/django-assets
 !     Push rejected, failed to compile Python app.
 !     Push failed

我不知道为什么它说导入错误，因为我已经在虚拟环境中安装了psycopg2。导入时，python shell甚至没有抛出任何错误，并且可以在本地计算机上成功运行服务器

在我的requirements.txt文件中，那里列出了psycopg2 == 2.8.3。

我的Pipfile

[[source]]
name = "pypi"
url = "https://pypi.org/simple"
verify_ssl = true

[dev-packages]

[packages]
django = "<2.3,>=2.2"
wagtail = "<2.6,>=2.5"

[requires]
python_version = "3.7"

我的数据库配置位于设置文件夹的base.py中

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'personalsite',
    }
}

在我的设置文件夹的production.py中

DATABASES['default'] = dj_database_url.config()

in requirements.txt

psycopg2==2.8.2
beautifulsoup4==4.6.0
certifi==2019.6.16
chardet==3.0.4
dj-database-url==0.5.0
dj-static==0.0.6
Django==2.2.2
django-modelcluster==4.4
django-taggit==0.24.0
django-toolbelt==0.0.1
django-treebeard==4.3
djangorestframework==3.9.4
draftjs-exporter==2.1.6
gunicorn==19.9.0
html5lib==1.0.1
idna==2.8
Pillow==5.4.1
pytz==2019.1
requests==2.22.0
six==1.12.0
sqlparse==0.3.0
static3==0.7.0
Unidecode==1.1.0
urllib3==1.25.3
wagtail==2.5.1
webencodings==0.5.1
Willow==1.1

Answer 1

似乎您将所有这些软件包都安装到了本地Python安装中，而不是安装到了虚拟环境中。您的 Pipfile 没有反映诸如psycopg2，dj_database_url等之类的软件包。请将这些软件包安装到您的虚拟环境中。

首先，激活您的虚拟环境，

pipenv shell

然后安装以下软件包，

pipenv install psycopg2-binary 
pipenv install dj-database-url

运行pipenv lock以生成适当的Pipfile.lock。然后尝试使用以下命令将其再次推送到 Heroku 。

push heroku master