Hey, I am new to the pants ecosystem and I am trying to build a monorepo for my django projects. Here is the dir structure that I have

.
├── 3rdparty
│   └── python
│       └── default.lock
├── BUILD
├── pants
├── pants.toml
├── poetry.lock
├── projects
│   ├── proj1
│   │   ├── BUILD
│   │   ├── manage.py
│   │   └── proj1
│   │       ├── BUILD
│   │       ├── __init__.py
│   │       ├── asgi.py
│   │       ├── settings.py
│   │       ├── urls.py
│   │       └── wsgi.py
│   └── proj2
│       ├── ...
└── pyproject.toml

Here's my pants.toml:

[GLOBAL]
pants_version = "2.12.0"
backend_packages.add = [
  'pants.backend.python',
]

[anonymous-telemetry]
enabled = false

[source]
root_patterns = ["/"]

[python]
enable_resolves = true
lockfile_generator = "pex"

[python-infer]
string_imports = true

Here's my projects/proj1/BUILD:

pex_binary(
    name="manage",
    entry_point="manage.py",
)

python_sources()

Here's my projects/proj1/proj1/BUILD:

python_sources()

I am trying to run the runserver command with pants:

./pants run projects/proj1/:manage -- runserver

But I am getting an error with stack trace:

Traceback (most recent call last):
  File "/Users/reksus/.cache/pants/named_caches/pex_root/installed_wheels/115baf5049d5cf4163e43492cdc7139c306ed6d451e7d3571fe9612903903713/Django-3.2.15-py3-none-any.whl/django/core/management/base.py", line 354, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/reksus/.cache/pants/named_caches/pex_root/installed_wheels/115baf5049d5cf4163e43492cdc7139c306ed6d451e7d3571fe9612903903713/Django-3.2.15-py3-none-any.whl/django/core/management/commands/runserver.py", line 61, in execute
    super().execute(*args, **options)
  File "/Users/reksus/.cache/pants/named_caches/pex_root/installed_wheels/115baf5049d5cf4163e43492cdc7139c306ed6d451e7d3571fe9612903903713/Django-3.2.15-py3-none-any.whl/django/core/management/base.py", line 398, in execute
    output = self.handle(*args, **options)
  File "/Users/reksus/.cache/pants/named_caches/pex_root/installed_wheels/115baf5049d5cf4163e43492cdc7139c306ed6d451e7d3571fe9612903903713/Django-3.2.15-py3-none-any.whl/django/core/management/commands/runserver.py", line 68, in handle
    if not settings.DEBUG and not settings.ALLOWED_HOSTS:
  File "/Users/reksus/.cache/pants/named_caches/pex_root/installed_wheels/115baf5049d5cf4163e43492cdc7139c306ed6d451e7d3571fe9612903903713/Django-3.2.15-py3-none-any.whl/django/conf/__init__.py", line 82, in __getattr__
    self._setup(name)
  File "/Users/reksus/.cache/pants/named_caches/pex_root/installed_wheels/115baf5049d5cf4163e43492cdc7139c306ed6d451e7d3571fe9612903903713/Django-3.2.15-py3-none-any.whl/django/conf/__init__.py", line 69, in _setup
    self._wrapped = Settings(settings_module)
  File "/Users/reksus/.cache/pants/named_caches/pex_root/installed_wheels/115baf5049d5cf4163e43492cdc7139c306ed6d451e7d3571fe9612903903713/Django-3.2.15-py3-none-any.whl/django/conf/__init__.py", line 170, in __init__
    mod = importlib.import_module(self.SETTINGS_MODULE)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'proj1'

I tried updating the projects/proj1/BUILD:

pex_binary(
    name="manage",
    entry_point="manage.py",
    dependencies=[
        "projects/proj1/proj1:proj1",
    ]
)

python_sources()

But still the same error. What am I missing here?

What are the import statements you are using? I feel like it's imported as

from proj1 ..

If that's the case then your

root_patterns

should have

projects

Yeah you are right, since manage.py has this line

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'proj1.settings')

which require projects/proj1/ to be in pythonpath so I fixed by updating pants.toml

[source]
root_patterns = ["/"]
marker_filenames = ["manage.py"]

How do you define your 3rd party dependencies (basically packages like Django)? Do you use

requirements.txt

? I don't see anywhere the code you have pasted here. As mentioned in this doc you can see all the dependencies (1st and 2nd) using

dependencies

command and it can be transitive too. So I would debug using that https://www.pantsbuild.org/docs/python-third-party-dependencies

I am using poetry top level pyproject.toml

[tool.poetry]
name = "monorepo"
version = "0.1.0"
description = ""
authors = ["Tarun Tyagi"]
readme = "README.md"

[tool.poetry.dependencies]
python = "^3.9"
Django = "^3.2"


[build-system]
requires = ["poetry-core"]
build-backend = "poetry.core.masonry.api"

top level BUILD:

pex_binary(
    name="django-admin",
    dependencies=[
        ":poetry#Django",
    ],
    script="django-admin",
)


poetry_requirements(name="poetry")

Yeah so I would run

dependencies

command and see if

django

shows up or not. Are you able to run it outside pants with just python?

> ./pants dependencies projects/proj1/manage.py 
//:poetry#Django
projects/proj1/manage.py
projects/proj1/proj1/__init__.py
projects/proj1/proj1/asgi.py
projects/proj1/proj1/settings.py
projects/proj1/proj1/urls.py
projects/proj1/proj1/wsgi.py

Maybe I didn't write my earlier message clearly: This command doesn't work and says no module named django

./pants run projects/proj1:manage -- runserver

But the following is working. So I have this working now.

./pants run projects/proj1:manage -- runserver --noreload

I am actually asking what difference does --noreload make as far as pants is concerned? And in the github example-django the --noreload flag is not required with runserver cmd, so how can that be made possible here?

Ah ok! Sorry I might have also missed your question. Yeah this I am not sure about. Seems something django specific.

No problem Shantanu, thanks though. Btw --noreload simple stops reloading server on live code changes, i.e. doens't update the code already loaded in memory. Many languages have this live reloading feature. Maybe this could help you in helping me find the fix.

Ah yes - if I remember correctly, the way the Django autoreloader works interacts badly with Pants’s hermetic sandboxes, and gives that error (the autoreloader has some very unusual syspath hacking).