Package Installation Not working with uv, ModuleNotFoundError: No module named 'rest_framework'

[dkcshivam]

Hi,

Steps to Recreate:

1. Initialize a project using cookiecutter.
2. Choose docker as yes
3. build and run the project, it will work
4. add a new package in the pyproject.toml (eg:djangorestframework)
5. run docker compose -f docker-compose.local.yml run --rm django uv lock
6. build the image again
7. run the container, it will work.
8. Now go into the config/settings/base.py file and put "rest_framework", inside THIRD_PARTY_APPS.
9. build the image
10. run the container, you will see error. ModuleNotFoundError: No module named 'rest_framework'I installed rest framework just for dummy, I know we can directly install it from the cookiecutter, in all of my recent projects with cookiecutter , whenever I try to use a new package it doesn't work. Seems like it's not getting installed inside the environment. In the 6th step when I went into the bash of the container and did pip freeze it did not showed rest_framework, so I knew that it will fail in the 7,8 and 9 steps.

Seems like some issue with the docker compose / docker file . Not sure exactly about it.

Earlier when pip was being used to install packages it was working like them. Here are the details.

My configurations:

Machine: Macbook Pro
Chip: Apple M3 Max
Memory: 48 GB
macOS: Tahoe 26.0

Docker version 28.5.1, build e180ab8
docker desktop: 4.48.0 (207573)

cookie-cutter version(maybe latest): 11 Oct 2025 2:44 pm from here: cookiecutter gh:cookiecutter/cookiecutter-django . And chose when prompted to download the latest.

Dockerfile
######################################################################################################
`# define an alias for the specific python version used in this file.
FROM ghcr.io/astral-sh/uv:python3.13-bookworm-slim AS python

Python build stage

FROM python AS python-build-stage

ARG APP_HOME=/app

WORKDIR ${APP_HOME}

we need to move the virtualenv outside of the $APP_HOME directory because it will be overriden by the docker compose mount

ENV UV_COMPILE_BYTECODE=1 UV_LINK_MODE=copy UV_PYTHON_DOWNLOADS=0

Install apt packages

RUN apt-get update && apt-get install --no-install-recommends -y \

dependencies for building Python packages

build-essential \

psycopg dependencies

libpq-dev
gettext
wait-for-it

Requirements are installed here to ensure they will be cached.

RUN --mount=type=cache,target=/root/.cache/uv
--mount=type=bind,source=pyproject.toml,target=pyproject.toml
--mount=type=bind,source=uv.lock,target=uv.lock:rw
uv sync --no-install-project

COPY . ${APP_HOME}

RUN --mount=type=cache,target=/root/.cache/uv
--mount=type=bind,source=pyproject.toml,target=pyproject.toml
--mount=type=bind,source=uv.lock,target=uv.lock:rw
uv sync

devcontainer dependencies and utils

RUN apt-get update && apt-get install --no-install-recommends -y
sudo git bash-completion nano ssh

Create devcontainer user and add it to sudoers

RUN groupadd --gid 1000 dev-user
&& useradd --uid 1000 --gid dev-user --shell /bin/bash --create-home dev-user
&& echo dev-user ALL=(root) NOPASSWD:ALL > /etc/sudoers.d/dev-user
&& chmod 0440 /etc/sudoers.d/dev-user

ENV PATH="/${APP_HOME}/.venv/bin:$PATH"
ENV PYTHONPATH="${APP_HOME}/.venv/lib/python3.13/site-packages:$PYTHONPATH"

COPY ./compose/production/django/entrypoint /entrypoint
RUN sed -i 's/\r$//g' /entrypoint
RUN chmod +x /entrypoint

COPY ./compose/local/django/start /start
RUN sed -i 's/\r$//g' /start
RUN chmod +x /start

ENTRYPOINT ["/entrypoint"]
`
######################################################################################################

docker-compose.local.yml file
######################################################################################################
`volumes:
my_awesome_project_local_postgres_data: {}
my_awesome_project_local_postgres_data_backups: {}

services:
django:
build:
context: .
dockerfile: ./compose/local/django/Dockerfile
image: my_awesome_project_local_django
container_name: my_awesome_project_local_django
depends_on:
- postgres
volumes:
- /app/.venv
- .:/app:z
env_file:
- ./.envs/.local/.django
- ./.envs/.local/.postgres
ports:
- '8000:8000'
command: /start

postgres:
build:
context: .
dockerfile: ./compose/production/postgres/Dockerfile
image: my_awesome_project_production_postgres
container_name: my_awesome_project_local_postgres
volumes:
- my_awesome_project_local_postgres_data:/var/lib/postgresql/data
- my_awesome_project_local_postgres_data_backups:/backups
env_file:
- ./.envs/.local/.postgres
`
######################################################################################################

pyproject.toml

######################################################################################################
`# ==== pytest ====
[tool.pytest.ini_options]
minversion = "6.0"
addopts = "--ds=config.settings.test --reuse-db --import-mode=importlib"
python_files = [
"tests.py",
"test_*.py",
]

==== Coverage ====

[tool.coverage.run]
include = ["my_awesome_project/**"]
omit = ["/migrations/", "/tests/"]
plugins = ["django_coverage_plugin"]

==== mypy ====

[tool.mypy]
python_version = "3.13"
check_untyped_defs = true
ignore_missing_imports = true
warn_unused_ignores = true
warn_redundant_casts = true
warn_unused_configs = true
plugins = [
"mypy_django_plugin.main",
]

[[tool.mypy.overrides]]

Django migrations should not produce any errors:

module = ".migrations."
ignore_errors = true

[tool.django-stubs]
django_settings_module = "config.settings.test"

==== djLint ====

[tool.djlint]
blank_line_after_tag = "load,extends"
close_void_tags = true
format_css = true
format_js = true

TODO: remove T002 when fixed djlint/djLint#687

ignore = "H006,H030,H031,T002"
include = "H017,H035"
indent = 2
max_line_length = 119
profile = "django"

[tool.djlint.css]
indent_size = 2

[tool.djlint.js]
indent_size = 2

[tool.ruff]

Exclude a variety of commonly ignored directories.

extend-exclude = [
"/migrations/.py",
"staticfiles/*",
]

[tool.ruff.lint]
select = [
"F",
"E",
"W",
"C90",
"I",
"N",
"UP",
"YTT",
# "ANN", # flake8-annotations: we should support this in the future but 100+ errors atm
"ASYNC",
"S",
"BLE",
"FBT",
"B",
"A",
"COM",
"C4",
"DTZ",
"T10",
"DJ",
"EM",
"EXE",
"FA",
'ISC',
"ICN",
"G",
'INP',
'PIE',
"T20",
'PYI',
'PT',
"Q",
"RSE",
"RET",
"SLF",
"SLOT",
"SIM",
"TID",
"TC",
"INT",
# "ARG", # Unused function argument
"PTH",
"ERA",
"PD",
"PGH",
"PL",
"TRY",
"FLY",
# "NPY",
# "AIR",
"PERF",
# "FURB",
# "LOG",
"RUF",
]
ignore = [
"S101", # Use of assert detected https://docs.astral.sh/ruff/rules/assert/
"RUF012", # Mutable class attributes should be annotated with typing.ClassVar
"SIM102", # sometimes it's better to nest
# of types for comparison.
# Deactivated because it can make the code slow:
# https://github.com/astral-sh/ruff/issues/7871
]

[tool.ruff.lint.isort]
force-single-line = true

[dependency-groups]
dev = [
"coverage==7.10.7",
"django-coverage-plugin==3.2.0",
"django-debug-toolbar==6.0.0",
"django-extensions==4.1",
"django-stubs[compatible-mypy]==5.2.7",
"djlint==1.36.4",
"factory-boy==3.3.2",
"ipdb==0.13.13",
"mypy==1.18.2",
"pre-commit==4.3.0",
"psycopg[c]==3.2.10",
"pytest==8.4.2",
"pytest-django==4.11.1",
"pytest-sugar==1.1.1",
"ruff==0.14.0",
"sphinx==8.2.3",
"sphinx-autobuild==2025.8.25",
"werkzeug[watchdog]==3.1.3",
]

[project]
name = "my_awesome_project"
version = "0.1.0"
description = "Behold My Awesome Project!"
readme = "README.md"

license = { text = "MIT" }
authors = [
{ name = "Daniel Roy Greenfeld", email = "daniel-roy-greenfeld@example.com" },
]
requires-python = "==3.13.*"
dependencies = [
"argon2-cffi==25.1.0",
"collectfasta==3.3.1",
"crispy-bootstrap5==2025.6",
"django==5.2.7",
"django-allauth[mfa]==65.12.0",
"django-anymail[mailgun]==13.1",
"django-crispy-forms==2.4",
"django-environ==0.12.0",
"django-model-utils==5.0.0",
"django-redis==6.0.0",
"django-storages[s3]==1.14.6",
"gunicorn==23.0.0",
"hiredis==3.2.1",
"pillow==11.3.0",
"psycopg[c]==3.2.10",
"python-slugify==8.0.4",
"redis==6.4.0",
"djangorestframework==3.16.1"
]
`

[sebastian-code]

I'm experiencing the same issue, the only workaround I found with this, was to stop the local containers, delete them and rebuild the local compose from scratch. I didn't take note of the version, but I created the project on September 27, 2025, using the most recent version at the moment. Furthermore, I haven't tested it in production yet.

[dkcshivam]

I'm experiencing the same issue, the only workaround I found with this, was to stop the local containers, delete them and rebuild the local compose from scratch. I didn't take note of the version, but I created the project on September 27, 2025, using the most recent version at the moment. Furthermore, I haven't tested it in production yet.

In production I guess it will work, even though I haven't tested it. So, in my local docker compose file I have two services

1. live (mounted code) - Doesn't work
2. stable ( contains last build) - Works perfectly all the time

[Victhereum]

Any solution to this yet? I am unable to install new packages (I use Docker). I added the package to my dependency using uv add xxx and rebuilt the Docker image, and it kept telling me the package does not exist. I even tried manually, and it still failed. Please help

[dkcshivam]

@Victhereum Nope, not till now.

I am using the following and it's working for me without any issues.

Dockerfile :

# define an alias for the specific python version used in this file.
FROM ghcr.io/astral-sh/uv:python3.13-bookworm-slim AS python

# Python build stage
FROM python AS python-build-stage

ARG APP_HOME=/app

WORKDIR ${APP_HOME}

# Move virtualenv OUTSIDE /app to avoid volume mount override
ENV UV_COMPILE_BYTECODE=1 \
    UV_LINK_MODE=copy \
    UV_PYTHON_DOWNLOADS=0 \
    UV_PROJECT_ENVIRONMENT=/opt/.venv \
    VIRTUAL_ENV=/opt/.venv \
    PATH="/opt/.venv/bin:$PATH"

# Install apt packages
RUN apt-get update && apt-get install --no-install-recommends -y \
  build-essential \
  libpq-dev \
  gettext \
  curl \
  wait-for-it \
  && rm -rf /var/lib/apt/lists/*

# Create venv directory
RUN mkdir -p /opt/.venv

# Copy dependency files first
COPY pyproject.toml uv.lock ./

# Install dependencies without project
RUN uv sync --frozen --no-install-project

# Copy entire application
COPY . ${APP_HOME}

# Install project
RUN uv sync --frozen

# devcontainer dependencies and utils
RUN apt-get update && apt-get install --no-install-recommends -y \
  sudo git bash-completion nano ssh curl \
  && rm -rf /var/lib/apt/lists/*

# Create devcontainer user and add it to sudoers
RUN groupadd --gid 1000 dev-user \
  && useradd --uid 1000 --gid dev-user --shell /bin/bash --create-home dev-user \
  && echo dev-user ALL=\(root\) NOPASSWD:ALL > /etc/sudoers.d/dev-user \
  && chmod 0440 /etc/sudoers.d/dev-user

COPY ./compose/production/django/entrypoint /entrypoint
RUN sed -i 's/\r$//g' /entrypoint
RUN chmod +x /entrypoint

COPY ./compose/local/django/start /start
RUN sed -i 's/\r$//g' /start
RUN chmod +x /start

COPY ./compose/local/django/celery/worker/start /start-celeryworker
RUN sed -i 's/\r$//g' /start-celeryworker
RUN chmod +x /start-celeryworker

COPY ./compose/local/django/celery/beat/start /start-celerybeat
RUN sed -i 's/\r$//g' /start-celerybeat
RUN chmod +x /start-celerybeat

COPY ./compose/local/django/celery/flower/start /start-flower
RUN sed -i 's/\r$//g' /start-flower
RUN chmod +x /start-flower

ENTRYPOINT ["/entrypoint"]

docker-compose.local.yml file:

services:
  django: &django
    build:
      context: .
      dockerfile: ./compose/local/django/Dockerfile
    image: project_local_django
    container_name: project_local_django_live
    depends_on:
      - postgres
      - redis
      - mailpit
    volumes:
      - .:/app:z
    env_file:
      - ./.envs/.local/.django
      - ./.envs/.local/.postgres
    environment:
      - SITE_PORT=8000
      - PYTHONPATH=/app
    ports:
      - '48000:8000'
    command: /start

  django_stable:
    <<: *django
    container_name: project_local_django_stable
    volumes: []
    environment:
      - SITE_PORT=8001
      - PYTHONPATH=/app
    ports:
      - '48001:8000'