****************
IDF Docker Image
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:link_to_translation:`zh_CN:[中文]`

..
    When changing this page, please keep tools/docker/README.md in sync.

.. highlight:: bash

IDF Docker image (``espressif/idf``) is intended for building applications and libraries with specific versions of ESP-IDF when doing automated builds.

The image contains:

- Common utilities such as ``git``, ``wget``, ``curl``, and ``zip``.
- Python 3.8 or newer.
- A copy of a specific version of ESP-IDF. See below for information about versions. ``IDF_PATH`` environment variable is set and points to the ESP-IDF location in the container.
- All the build tools required for the specific version of ESP-IDF: CMake, Ninja, cross-compiler toolchains, etc.
- All Python packages required by ESP-IDF are installed in a virtual environment.

The image ``ENTRYPOINT`` sets up the ``PATH`` environment variable to point to the correct version of tools, and activates the Python virtual environment. As a result, the environment is ready to use the ESP-IDF build system.

The image can also be used as a base for custom images, if additional utilities are required.

Tags
====

Multiple tags of this image are maintained:

- ``latest``: tracks ``master`` branch of ESP-IDF
- ``vX.Y``: corresponds to ESP-IDF release ``vX.Y``
- ``release-vX.Y``: tracks ``release/vX.Y`` branch of ESP-IDF

.. note::

    Versions of ESP-IDF released before this feature was introduced do not have corresponding Docker image versions. You can check the up-to-date list of available tags at https://hub.docker.com/r/espressif/idf/tags.

Usage
=====

Setting up Docker
~~~~~~~~~~~~~~~~~

Before using the ``espressif/idf`` Docker image locally, make sure you have Docker installed. Follow the instructions at https://docs.docker.com/install/, if it is not installed yet.

If using the image in a CI environment, consult the documentation of your CI service on how to specify the image used for the build process.

Building a Project with CMake
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In the project directory, run:

.. code-block:: bash

    docker run --rm -v $PWD:/project -w /project -u $UID -e HOME=/tmp espressif/idf idf.py build

The above command explained:

- ``docker run``: runs a Docker image. It is a shorter form of the command ``docker container run``.
- ``--rm``: removes the container when the build is finished.
- ``-v $PWD:/project``: mounts the current directory on the host (``$PWD``) as ``/project`` directory in the container.
- ``-w /project``: makes ``/project`` the working directory for the command.
- ``-u $UID``: makes the command run with your user ID so that files are created as you (instead of root).
- ``-e HOME=/tmp``: gives the user a home directory for storing temporary files created by ``idf.py`` in ``~/.cache``.
- ``espressif/idf``: uses Docker image ``espressif/idf`` with tag ``latest``. The ``latest`` tag is implicitly added by Docker when no tag is specified.
- ``idf.py build``: runs this command inside the container.

.. note::

   When the mounted directory, ``/project``, contains a git repository owned by a different user (``UID``) than the one running the Docker container, git commands executed within ``/project`` might fail, displaying an error message ``fatal: detected dubious ownership in repository at '/project'``. To resolve this issue, you can designate the ``/project`` directory as safe by setting the IDF_GIT_SAFE_DIR environment variable during the Docker container startup. For instance, you can achieve this by including ``-e IDF_GIT_SAFE_DIR='/project'`` as a parameter. Additionally, multiple directories can be specified by using a ``:`` separator. To entirely disable this git security check, ``*`` can be used.

To build with a specific Docker image tag, specify it as ``espressif/idf:TAG``, for example:

.. code-block:: bash

    docker run --rm -v $PWD:/project -w /project -u $UID -e HOME=/tmp espressif/idf:release-v4.4 idf.py build

You can check the up-to-date list of available tags at https://hub.docker.com/r/espressif/idf/tags.

Using the Image Interactively
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

It is also possible to do builds interactively, to debug build issues or test the automated build scripts. Start the container with ``-i -t`` flags:

.. code-block:: bash

    docker run --rm -v $PWD:/project -w /project -u $UID -e HOME=/tmp -it espressif/idf

Then inside the container, use ``idf.py`` as usual:

.. code-block:: bash

    idf.py menuconfig
    idf.py build

.. note::

    Commands which communicate with the development board, such as ``idf.py flash`` and ``idf.py monitor`` does not work in the container, unless the serial port is passed through into the container. This can be done with Docker for Linux with the `device option`_. However, currently, this is not possible with Docker for Windows (https://github.com/docker/for-win/issues/1018) and Docker for Mac (https://github.com/docker/for-mac/issues/900). This limitation may be overcome by using `remote serial ports`_. An example of how to do this can be found in the following `using remote serial port`_ section.

.. note::

    On Linux, when adding the host serial port device into the container using options like ``--device`` or ``--privileged``, and starting the container with a specific user using ``-u $UID``, ensure that this user has read/write access to the device. This can be achieved by adding the container user into the group ID that is assigned to the device on the host, using the ``--group-add`` option. For instance, if the host device has the ``dialout`` group assigned, you can utilize ``--group-add $(getent group dialout | cut -d':' -f3)`` to add the container user to the host's ``dialout`` group.


.. _using remote serial port:

Using Remote Serial Port
~~~~~~~~~~~~~~~~~~~~~~~~

The `RFC2217`_ (Telnet) protocol can be used to remotely connect to a serial port. For more information please see the `remote serial ports`_ documentation in the ESP tool project. This method can also be used to access the serial port inside a Docker container if it cannot be accessed directly. Following is an example of how to use the Flash command from within a Docker container.

On host install and start ``esp_rfc2217_server``:

* On Windows, the package is available as a one-file bundled executable created by ``pyinstaller`` and it can be downloaded from the `esptool releases`_ page in a ZIP archive along with other ESP tool utilities:

.. code-block:: bash

    esp_rfc2217_server -v -p 4000 COM3

* On Linux or macOS, the package is available as part of ``esptool``, which can be found in the ESP-IDF environment or by installing using ``pip``:

.. code-block:: bash

    pip install esptool

And then starting the server by executing

.. code-block:: bash

    esp_rfc2217_server.py -v -p 4000 /dev/ttyUSB0

Now the device attached to the host can be flashed from inside a Docker container by using:

.. code-block:: bash

    docker run --rm -v <host_path>:/<container_path> -w /<container_path> espressif/idf idf.py --port 'rfc2217://host.docker.internal:4000?ign_set_control' flash

Please make sure that ``<host_path>`` is properly set to your project path on the host, and ``<container_path>`` is set as a working directory inside the container with the ``-w`` option. The ``host.docker.internal`` is a special Docker DNS name to access the host. This can be replaced with a host IP if necessary.


Building Custom Images
======================

The Docker file in ESP-IDF repository provides several build arguments which can be used to customize the Docker image:

- ``IDF_CLONE_URL``: URL of the repository to clone ESP-IDF from. Can be set to a custom URL when working with a fork of ESP-IDF. The default is ``https://github.com/espressif/esp-idf.git``.
- ``IDF_CLONE_BRANCH_OR_TAG``: Name of a git branch or tag used when cloning ESP-IDF. This value is passed to the ``git clone`` command using the ``--branch`` argument. The default is ``master``.
- ``IDF_CHECKOUT_REF``: If this argument is set to a non-empty value, ``git checkout $IDF_CHECKOUT_REF`` command performs after cloning. This argument can be set to the SHA of the specific commit to check out, for example, if some specific commit on a release branch is desired.
- ``IDF_CLONE_SHALLOW``: If this argument is set to a non-empty value, ``--depth=1 --shallow-submodules`` arguments are used when performing ``git clone``. Depth can be customized using ``IDF_CLONE_SHALLOW_DEPTH``. Doing a shallow clone significantly reduces the amount of data downloaded and the size of the resulting Docker image. However, if switching to a different branch in such a "shallow" repository is necessary, an additional ``git fetch origin <branch>`` command must be executed first.
- ``IDF_CLONE_SHALLOW_DEPTH``: This argument specifies the depth value to use when doing a shallow clone. If not set, ``--depth=1`` will be used. This argument has effect only if ``IDF_CLONE_SHALLOW`` is used. Use this argument if you are building a Docker image for a branch, and the image has to contain the latest tag on that branch. To determine the required depth, run ``git describe`` for the given branch and note the offset number. Increment it by 1, then use it as the value of this argument. The resulting image will contain the latest tag on the branch, and consequently ``git describe`` command inside the Docker image will work as expected.
- ``IDF_INSTALL_TARGETS``: Comma-separated list of ESP-IDF targets to install toolchains for, or ``all`` to install toolchains for all targets. Selecting specific targets reduces the amount of data downloaded and the size of the resulting Docker image. The default is ``all``.

To use these arguments, pass them via the ``--build-arg`` command line option. For example, the following command builds a Docker image with a shallow clone of ESP-IDF v4.4.1 and tools for ESP32-C3 only:

.. code-block:: bash

    docker build -t idf-custom:v4.4.1-esp32c3 \
        --build-arg IDF_CLONE_BRANCH_OR_TAG=v4.4.1 \
        --build-arg IDF_CLONE_SHALLOW=1 \
        --build-arg IDF_INSTALL_TARGETS=esp32c3 \
        tools/docker

.. _remote serial ports: https://docs.espressif.com/projects/esptool/en/latest/esptool/remote-serial-ports.html
.. _RFC2217: http://www.ietf.org/rfc/rfc2217.txt
.. _esptool releases: https://github.com/espressif/esptool/releases
.. _device option: https://docs.docker.com/engine/reference/run/#runtime-privilege-and-linux-capabilities