feat(dockerfile): Add pip caching for faster build

Dockerfile

@@ -553,9 +553,9 @@ function common::install_pip_version() {
     echo "${COLOR_BLUE}Installing pip version ${AIRFLOW_PIP_VERSION}${COLOR_RESET}"
     echo
     if [[ ${AIRFLOW_PIP_VERSION} =~ .*https.* ]]; then
-        pip install --disable-pip-version-check --no-cache-dir "pip @ ${AIRFLOW_PIP_VERSION}"
+        pip install --disable-pip-version-check "pip @ ${AIRFLOW_PIP_VERSION}"
     else
-        pip install --disable-pip-version-check --no-cache-dir "pip==${AIRFLOW_PIP_VERSION}"
+        pip install --disable-pip-version-check "pip==${AIRFLOW_PIP_VERSION}"
     fi
     mkdir -p "${HOME}/.local/bin"
 }
@@ -1123,7 +1123,7 @@ if [[ -n "${_PIP_ADDITIONAL_REQUIREMENTS=}" ]] ; then
     >&2 echo "         the container starts, so it is only useful for testing and trying out"
     >&2 echo "         of adding dependencies."
     >&2 echo
-    pip install --root-user-action ignore --no-cache-dir ${_PIP_ADDITIONAL_REQUIREMENTS}
+    pip install --root-user-action ignore ${_PIP_ADDITIONAL_REQUIREMENTS}
 fi
 
 
@@ -1201,7 +1201,8 @@ SHELL ["/bin/bash", "-o", "pipefail", "-o", "errexit", "-o", "nounset", "-o", "n
 ARG PYTHON_BASE_IMAGE
 ENV PYTHON_BASE_IMAGE=${PYTHON_BASE_IMAGE} \
     DEBIAN_FRONTEND=noninteractive LANGUAGE=C.UTF-8 LANG=C.UTF-8 LC_ALL=C.UTF-8 \
-    LC_CTYPE=C.UTF-8 LC_MESSAGES=C.UTF-8
+    LC_CTYPE=C.UTF-8 LC_MESSAGES=C.UTF-8 \
+    PIP_CACHE_DIR=/tmp/.cache/pip
 
 ARG DEV_APT_DEPS=""
 ARG ADDITIONAL_DEV_APT_DEPS=""
@@ -1386,8 +1387,15 @@ WORKDIR ${AIRFLOW_HOME}
 COPY --from=scripts install_from_docker_context_files.sh install_airflow.sh \
      install_additional_dependencies.sh /scripts/docker/
 
-# hadolint ignore=SC2086, SC2010
-RUN if [[ ${INSTALL_PACKAGES_FROM_CONTEXT} == "true" ]]; then \
+# Useful for creating a cache id based on the underlying architecture, preventing the use of cached python packages from
+# an incorrect architecture.
+ARG TARGETARCH
+# Value to be able to easily change cache id and therefore use a bare new cache
+ARG PIP_CACHE_EPOCH="0"
+
+# hadolint ignore=SC2086, SC2010, DL3042
+RUN --mount=type=cache,id=$PYTHON_BASE_IMAGE-$AIRFLOW_PIP_VERSION-$TARGETARCH-$PIP_CACHE_EPOCH,target=/tmp/.cache/pip,uid=${AIRFLOW_UID} \
+  if [[ ${INSTALL_PACKAGES_FROM_CONTEXT} == "true" ]]; then \
         bash /scripts/docker/install_from_docker_context_files.sh; \
     fi; \
     if ! airflow version 2>/dev/null >/dev/null; then \
@@ -1405,8 +1413,10 @@ RUN if [[ ${INSTALL_PACKAGES_FROM_CONTEXT} == "true" ]]; then \
 # In case there is a requirements.txt file in "docker-context-files" it will be installed
 # during the build additionally to whatever has been installed so far. It is recommended that
 # the requirements.txt contains only dependencies with == version specification
-RUN if [[ -f /docker-context-files/requirements.txt ]]; then \
-        pip install --no-cache-dir --user -r /docker-context-files/requirements.txt; \
+# hadolint ignore=DL3042
+RUN --mount=type=cache,id=additional-requirements-$PYTHON_BASE_IMAGE-$AIRFLOW_PIP_VERSION-$TARGETARCH-$PIP_CACHE_EPOCH,target=/tmp/.cache/pip,uid=${AIRFLOW_UID} \
+    if [[ -f /docker-context-files/requirements.txt ]]; then \
+        pip install --user -r /docker-context-files/requirements.txt; \
     fi
 
 ##############################################################################################

Dockerfile.ci

@@ -513,9 +513,9 @@ function common::install_pip_version() {
     echo "${COLOR_BLUE}Installing pip version ${AIRFLOW_PIP_VERSION}${COLOR_RESET}"
     echo
     if [[ ${AIRFLOW_PIP_VERSION} =~ .*https.* ]]; then
-        pip install --disable-pip-version-check --no-cache-dir "pip @ ${AIRFLOW_PIP_VERSION}"
+        pip install --disable-pip-version-check "pip @ ${AIRFLOW_PIP_VERSION}"
     else
-        pip install --disable-pip-version-check --no-cache-dir "pip==${AIRFLOW_PIP_VERSION}"
+        pip install --disable-pip-version-check "pip==${AIRFLOW_PIP_VERSION}"
     fi
     mkdir -p "${HOME}/.local/bin"
 }

docs/docker-stack/build-arg-ref.rst

@@ -278,3 +278,6 @@ Docker context files.
 |                                          |                                          | This allows to optimize iterations for   |
 |                                          |                                          | Image builds and speeds up CI builds.    |
 +------------------------------------------+------------------------------------------+------------------------------------------+
+| ``PIP_CACHE_EPOCH``                      | ``"0"``                                  | Allow to invalidate cache by passing a   |
+|                                          |                                          | new argument.                            |
++------------------------------------------+------------------------------------------+------------------------------------------+

docs/docker-stack/build.rst

@@ -972,3 +972,15 @@ The architecture of the images
 
 You can read more details about the images - the context, their parameters and internal structure in the
 `IMAGES.rst <https://github.com/apache/airflow/blob/main/IMAGES.rst>`_ document.
+
+
+Pip packages caching
+....................
+
+To enable faster iteration when building the image locally (especially if you are testing different combination of
+python packages), pip caching has been enabled. The caching id is based on four different parameters:
+
+1. ``PYTHON_BASE_IMAGE``: Avoid sharing same cache based on python version and target os
+2. ``AIRFLOW_PIP_VERSION``
+3. ``TARGETARCH``: Avoid sharing architecture specific cached package
+4. ``PIP_CACHE_EPOCH``: Enable changing cache id by passing ``PIP_CACHE_EPOCH`` as ``--build-arg``

docs/docker-stack/changelog.rst

@@ -58,6 +58,10 @@ here so that users affected can find the reason for the changes.
 Airflow 2.7
 ~~~~~~~~~~~
 
+* 2.7.4
+
+  * PIP caching for local builds has been enabled to speed up local custom image building
+
 * 2.7.3
 
   * Add experimental feature for select type of MySQL Client libraries during the build custom image via ``INSTALL_MYSQL_CLIENT_TYPE``

scripts/docker/common.sh

@@ -77,9 +77,9 @@ function common::install_pip_version() {
     echo "${COLOR_BLUE}Installing pip version ${AIRFLOW_PIP_VERSION}${COLOR_RESET}"
     echo
     if [[ ${AIRFLOW_PIP_VERSION} =~ .*https.* ]]; then
-        pip install --disable-pip-version-check --no-cache-dir "pip @ ${AIRFLOW_PIP_VERSION}"
+        pip install --disable-pip-version-check "pip @ ${AIRFLOW_PIP_VERSION}"
     else
-        pip install --disable-pip-version-check --no-cache-dir "pip==${AIRFLOW_PIP_VERSION}"
+        pip install --disable-pip-version-check "pip==${AIRFLOW_PIP_VERSION}"
     fi
     mkdir -p "${HOME}/.local/bin"
 }

scripts/docker/entrypoint_prod.sh

@@ -308,7 +308,7 @@ if [[ -n "${_PIP_ADDITIONAL_REQUIREMENTS=}" ]] ; then
     >&2 echo "         the container starts, so it is only useful for testing and trying out"
     >&2 echo "         of adding dependencies."
     >&2 echo
-    pip install --root-user-action ignore --no-cache-dir ${_PIP_ADDITIONAL_REQUIREMENTS}
+    pip install --root-user-action ignore ${_PIP_ADDITIONAL_REQUIREMENTS}
 fi