Move to managing devcontainer environment outside of dockerfile

Author: callumforrester

.devcontainer/devcontainer.json

@@ -7,7 +7,8 @@
     },
     "remoteEnv": {
         // Allow X11 apps to run inside the container
-        "DISPLAY": "${localEnv:DISPLAY}"
+        "DISPLAY": "${localEnv:DISPLAY}",
+        "PATH": "${containerEnv:PATH}:/workspaces/${localWorkspaceFolderBasename}/.venv/bin"
     },
     "customizations": {
         "vscode": {
@@ -39,8 +40,14 @@
         // Make sure SELinux does not disable with access to host filesystems like tmp
         "--security-opt=label=disable"
     ],
+    "mounts": [
+        {
+            "target": "/workspaces/${localWorkspaceFolderBasename}/.venv",
+            "type": "volume"
+        }
+    ],
     // Mount the parent as /workspaces so we can pip install peers as editable
     "workspaceMount": "source=${localWorkspaceFolder}/..,target=/workspaces,type=bind",
     // After the container is created, install the uv env
-    "postCreateCommand": "uv pip install $([ -f dev-requirements.txt ] && echo '-c dev-requirements.txt') -e '.[dev]' && pre-commit install"
+    "postCreateCommand": "uv venv --seed && uv sync --locked && pre-commit install"
 }

Dockerfile

@@ -3,19 +3,9 @@
 ARG PYTHON_VERSION=3.11
 FROM python:${PYTHON_VERSION} AS developer
 
-# Add any system dependencies for the developer/build environment here
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    graphviz \
-    && rm -rf /var/lib/apt/lists/*
+# Use this version of uv
+ARG UV_VERSION=0.7.4
 
-# Install uv using the official installer script
-RUN curl -LsSf https://astral.sh/uv/install.sh | \
-    env UV_INSTALL_DIR="/usr/local/bin" sh
-
-# Configure environment
-ENV UV_CHECK_UPDATE=false
-
-# Create virtual environment
-RUN uv venv --seed venv
-ENV VIRTUAL_ENV=/venv
-ENV PATH=$VIRTUAL_ENV/bin:$PATH
+# Install uv using the official image
+# See https://docs.astral.sh/uv/guides/integration/docker/#installing-uv
+COPY --from=ghcr.io/astral-sh/uv:${UV_VERSION} /uv /uvx /bin/

pyproject.toml

@@ -7,7 +7,7 @@ name = "python-copier-template"
 dynamic = ["version"]
 requires-python = ">=3.11"
 
-[project.optional-dependencies]
+[dependency-groups]
 dev = [
     "copier",
     "myst-parser",

template/Dockerfile.jinja

@@ -3,38 +3,47 @@
 ARG PYTHON_VERSION=3.11
 FROM python:${PYTHON_VERSION} AS developer
 
-# Add any system dependencies for the developer/build environment here
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    graphviz \
-    && rm -rf /var/lib/apt/lists/*
-
-# Install uv using the official installer script
-RUN curl -LsSf https://astral.sh/uv/install.sh | \
-    env UV_INSTALL_DIR="/usr/local/bin" sh
+# Use this version of uv
+ARG UV_VERSION=0.7.4
 
-# Configure environment
-ENV UV_CHECK_UPDATE=false
+# Add any system dependencies for the developer/build environment here
+# RUN apt-get update && apt-get install -y --no-install-recommends \
+#     graphviz
 
-# Create virtual environment
-RUN uv venv --seed venv
-ENV VIRTUAL_ENV=/venv
-ENV PATH=$VIRTUAL_ENV/bin:$PATH{% if docker %}
+# Install uv using the official image
+# See https://docs.astral.sh/uv/guides/integration/docker/#installing-uv
+COPY --from=ghcr.io/astral-sh/uv:${UV_VERSION} /uv /uvx /bin/
 
 # The build stage installs the context into the venv
 FROM developer AS build
 COPY . /context
 WORKDIR /context
 
-# install dependencies and project into the local packages directory
-RUN touch dev-requirements.txt && uv pip install -c dev-requirements.txt .
+# Enable bytecode compilation and copy from the cache instead of linking 
+# since it's a mounted volume
+ENV UV_COMPILE_BYTECODE=1
+ENV UV_LINK_MODE=copy
+
+# Install the project's dependencies using the lockfile and settings
+RUN --mount=type=cache,target=/root/.cache/uv \
+    --mount=type=bind,source=uv.lock,target=uv.lock \
+    --mount=type=bind,source=pyproject.toml,target=pyproject.toml \
+    uv sync --locked --no-install-project --no-dev
+
+# Then, add the rest of the project source code and install it
+# Installing separately from its dependencies allows optimal layer caching
+COPY . /context
+RUN --mount=type=cache,target=/root/.cache/uv \
+    uv sync --locked --no-dev
 
 # The runtime stage copies the built venv into a slim runtime container
 FROM python:${PYTHON_VERSION}-slim AS runtime
 # Add apt-get system dependecies for runtime here if needed
-COPY --from=build /venv/ .venv/
-ENV VIRTUAL_ENV=./.venv
-ENV PATH=$VIRTUAL_ENV/bin:$PATH
 
-# change this entrypoint if it is not the same as the repo
+# We need to keep the venv at the same absolute path as in the build stage
+COPY --from=build /context/venv/ /context/venv/
+ENV PATH=/context/venv/bin:$PATH
+
+# Change this entrypoint if it is not the same as the repo
 ENTRYPOINT ["{{ repo_name }}"]
 CMD ["--version"]{% endif %}