如何在Heroku上使用python-magic？

Question

我正在构建一个使用python-magic 0.4.15的应用程序。 在我的本地计算机上， python-magic-bin 0.4.15的运行方式就像一个超级按钮 （Windows），但我试图使其在Heroku上运行。 首先，我只是想让测试通过Heroku-CI。 我将包添加到我的requirements.txt ：

python-magic==0.4.15

并将其推送到Heroku。 并正确安装：

-----> Installing requirements with pip
       Collecting python-magic==0.4.15 (from -r /app/requirements.txt (line 7))
         Downloading https://files.pythonhosted.org/packages/42/a1/76d30c79992e3750dac6790ce16f056f870d368ba142f83f75f694d93001/python_magic-0.4.15-py2.py3-none-any.whl
       Installing collected packages: python-magic
       Successfully installed python-magic-0.4.15

但是然后它像这样崩溃：

+ python manage.py collectstatic --no-input
Traceback (most recent call last):
  File "manage.py", line 20, in <module>
    execute_from_command_line(sys.argv)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 357, in execute
    django.setup()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/apps/registry.py", line 120, in populate
    app_config.ready()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/apps.py", line 24, in ready
    self.module.autodiscover()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/__init__.py", line 26, in autodiscover
    autodiscover_modules('admin', register_to=site)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/module_loading.py", line 47, in autodiscover_modules
    import_module('%s.%s' % (app_config.name, module_to_search))
  File "/app/.heroku/python/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/app/core/admin.py", line 8, in <module>
    from .forms import CrmDataUploadForm
  File "/app/core/forms.py", line 3, in <module>
    from magic import magic
ImportError: cannot import name 'magic'

我尝试添加NetsoftHoldings / heroku-buildpack-magic buildpack ，可以看到正在下载它：

-----> Fetching https://github.com/NetsoftHoldings/heroku-buildpack-magic.git buildpack...
       buildpack downloaded

pip软件包已正确安装：

-----> Installing requirements with pip
       Collecting python-magic==0.4.15 (from -r /app/requirements.txt (line 7))
         Downloading https://files.pythonhosted.org/packages/42/a1/76d30c79992e3750dac6790ce16f056f870d368ba142f83f75f694d93001/python_magic-0.4.15-py2.py3-none-any.whl
       Installing collected packages: python-magic
       Successfully installed python-magic-0.4.15

但是然后buildbuild似乎有错误（我在这里猜）：

-----> libmagic app detected
bash: /tmp/buildpacks/27353aa3b5edb2f8361186206e863f5d481f02805d02f0efdec439f3d30349a4fbdad2951af33a0492023fb0d90d26dafda6fe76f1b2d34f68564a98545f7022/export: No such file or directory
RootDir: /tmp/buildpacks/ba9220b10d71b7b776013869da2c820ccb5c0f1733268ae2515b3b8ad5edd44d2016d1119bce32d1660fbd84da179891a404dcc57df043b9d82e22725739b072
BuildDir: /app
HOME: /app
Build list
config
Home list
config

最终像这样崩溃：

+ python manage.py collectstatic --no-input
Traceback (most recent call last):
  File "manage.py", line 20, in <module>
    execute_from_command_line(sys.argv)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 357, in execute
    django.setup()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/apps/registry.py", line 120, in populate
    app_config.ready()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/apps.py", line 24, in ready
    self.module.autodiscover()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/__init__.py", line 26, in autodiscover
    autodiscover_modules('admin', register_to=site)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/module_loading.py", line 47, in autodiscover_modules
    import_module('%s.%s' % (app_config.name, module_to_search))
  File "/app/.heroku/python/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/app/core/admin.py", line 8, in <module>
    from .forms import CrmDataUploadForm
  File "/app/core/forms.py", line 3, in <module>
    from magic import magic
ImportError: cannot import name 'magic'

然后我尝试添加heroku-community/apt buildpack和一个包含以下内容的Aptfile：

libmagic-dev
libmagic1

我可以看到它们已正确安装：

-----> Fetching .debs for libmagic-dev
       Reading package lists...
       Building dependency tree...
       0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 23 not upgraded.
       Need to get 79.4 kB of archives.
       After this operation, 0 B of additional disk space will be used.
       Get:1 http://archive.ubuntu.com/ubuntu bionic-security/main amd64 libmagic-dev amd64 1:5.32-2ubuntu0.1 [79.4 kB]
       Fetched 79.4 kB in 0s (222 kB/s)
       Download complete and in download only mode
W: --force-yes is deprecated, use one of the options starting with --allow instead.
-----> Fetching .debs for libmagic1
       Reading package lists...
       Building dependency tree...
       0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 23 not upgraded.
       Need to get 68.4 kB of archives.
       After this operation, 0 B of additional disk space will be used.
       Get:1 http://archive.ubuntu.com/ubuntu bionic-security/main amd64 libmagic1 amd64 1:5.32-2ubuntu0.1 [68.4 kB]
       Fetched 68.4 kB in 0s (199 kB/s)
       Download complete and in download only mode
W: --force-yes is deprecated, use one of the options starting with --allow instead.
-----> Installing libmagic1_1%3a5.32-2ubuntu0.1_amd64.deb
-----> Installing libmagic-dev_1%3a5.32-2ubuntu0.1_amd64.deb

但是应用程序仍然失败，并显示相同的错误：

+ pip install -r requirements-test.txt
Requirement already satisfied: coverage==4.5.1 in ./.heroku/python/lib/python3.6/site-packages (from -r requirements-test.txt (line 1))
Requirement already satisfied: selenium==3.141.0 in ./.heroku/python/lib/python3.6/site-packages (from -r requirements-test.txt (line 2))
Requirement already satisfied: urllib3 in ./.heroku/python/lib/python3.6/site-packages (from selenium==3.141.0->-r requirements-test.txt (line 2))
You are using pip version 9.0.2, however version 18.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
+ python manage.py collectstatic --no-input
Traceback (most recent call last):
  File "manage.py", line 20, in <module>
    execute_from_command_line(sys.argv)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 357, in execute
    django.setup()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/apps/registry.py", line 120, in populate
    app_config.ready()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/apps.py", line 24, in ready
    self.module.autodiscover()
  File "/app/.heroku/python/lib/python3.6/site-packages/django/contrib/admin/__init__.py", line 26, in autodiscover
    autodiscover_modules('admin', register_to=site)
  File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/module_loading.py", line 47, in autodiscover_modules
    import_module('%s.%s' % (app_config.name, module_to_search))
  File "/app/.heroku/python/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/app/core/admin.py", line 8, in <module>
    from .forms import CrmDataUploadForm
  File "/app/core/forms.py", line 3, in <module>
    from magic import magic
ImportError: cannot import name 'magic'

有什么想法如何使python-magic在Heroku上工作吗？

Answer 1

导入magic模块的正确方法是：

import magic

不

from magic import magic

python-magic只是提供了一个magic模块，而python-magic-bin也是一样。 问题在于python-magic-bin有一个名为magic的包，该包导入模块magic.magic ，有点像内部细节，因此，后一个示例在python-magic-bin中起作用，而在python-magic中不起作用。

从python-magic文档中：

>>> import magic
>>> magic.from_file("testdata/test.pdf")
'PDF document, version 1.2'
>>> magic.from_buffer(open("testdata/test.pdf").read(1024))
'PDF document, version 1.2'
>>> magic.from_file("testdata/test.pdf", mime=True)
'application/pdf'