You'll find Docker files for .NET nanoFramework. They are used to facilitate building images.

The available pre build images are:

• ghcr.io/nanoframework/dev-container-all: contains all elements to build a firmware image for any of the targets. Important: the size of this container is very large, if you are interested only in building targets on a single platform, you're better using one of the following images specific to that platform.
• ghcr.io/nanoframework/dev-container-chibios: contains all elements to build a firmware image for any of the ChibiOS targets
• ghcr.io/nanoframework/dev-container-ti: contains all elements to build a firmware image for any of the TI SimpleLink targets
• ghcr.io/nanoframework/dev-container-esp32: contains all elements to build a firmware image for any of the ESP32 targets
• ghcr.io/nanoframework/dev-container-azure-rtos: contains all elements to build a firmware image for any of the Eclipse ThreadX (used to be Azure RTOS) targets
• ghcr.io/nanoframework/dev-container-freertos-nxp: contains all elements to build a firmware image for any of the NXP targets
• ChibiOS-RP: contains all elements to build a firmware image for Raspberry Pi Pico (RP2040/RP2350) ChibiOS targets. Uses ChibiOS master branch which includes RP support.

You can choose the dev container needed when opening a remote container in VSCode. The options are:

• nanoFramework-All to use the pre build container with all the elements to build a firmware image for any of the targets
• nanoFramework-ThreadX to use the pre build container with all the elements to build Eclipse ThreadX (used to be Azure RTOS) targets
• nanoFramework-ChibiOS to use the pre build container with all the elements to build ChibiOS targets
• nanoFramework-ESP32 to use the pre build container with all the elements to build ESP32 targets
• nanoFramework-TI to use the pre build container with all the elements to build TI SimpleLink targets
• nanoFramework-FreeRTOS-NXP to use the pre build container with all the elements to build TI SimpleLink targets
• nanoFramework-ChibiOS-RP to build from source a container with all the elements to build Raspberry Pi Pico RP2040/RP2350 ChibiOS targets

To use the source dockerfile for the respective platform adjust its devcontainer.json file and change the "dockerFile": "Dockerfile.<platform>" element for the image you would like to use:

• Dockerfile.All.SRC to build the container image from the source with all the elements to build all the images
• Dockerfile.ThreadX.SRC to build the container image from the source with all the elements to build Eclipse ThreadX (used to be Azure RTOS) based devices
• Dockerfile.ChibiOS.SRC to build the container image from the source with all the elements to build ChibiOS based devices
• Dockerfile.ESP32.SRC to build the container image from the source with all the elements to build ESP32 based devices
• Dockerfile.TI.SRC to build the container image from the source with all the elements to build TI SimpleLink based devices
• Dockerfile.FreeRTOS.NXP.SRC to build the container image from the source with all the elements to build NXP based devices
• Dockerfile.ChibiOS-RP.SRC to build the container image from the source with all the elements to build Raspberry Pi Pico (RP2040/RP2350) ChibiOS targets

Add a "repository variable" called PUBLISH_DOCKER_IMAGE with the value true in your forked repository See: https://docs.github.com/en/actions/learn-github-actions/variables#creating-configuration-variables-for-a-repository for further help.

Note: by default, the build and publish of the devcontainer docker images will still only happen when the docker source files change and are "pushed" to the main branch.