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IDF Docker Image
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..
    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, zip.
- Python 3.7 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 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 ``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 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::

    docker run --rm -v $PWD:/project -w /project 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
- ``espressif/idf``: uses Docker image ``espressif/idf`` with tag ``latest`` (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::

    docker run --rm -v $PWD:/project -w /project 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::

    docker run --rm -v $PWD:/project -w /project -it espressif/idf


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

    idf.py menuconfig
    idf.py build

.. note::

    Commands which communicate with the development board, such as ``idf.py flash`` and ``idf.py monitor`` will 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 how to do this can be found in the following `using remote serial port`_ section.


.. _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 esptool 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 how to use the flash command from within a Docker container.

On host install and start ``esp_rfc2217_server``:

* On Windows, 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 esptool utilities::

        esp_rfc2217_server -v -p 4000 COM3

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

        pip install esptool

  And then starting the server by executing::

        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::

    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 host IP if necessary.


Building custom images
======================

The Dockerfile 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 will build a Docker image with a shallow clone of ESP-IDF v4.4.1 and tools for ESP32-C3, only::

    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