Configure IoT Edge module build options

Applies to: IoT Edge 1.5

Important

IoT Edge 1.5 LTS is the supported release. IoT Edge 1.4 LTS is end of life as of November 12, 2024. If you are on an earlier release, see Update IoT Edge.

The module.json file controls how modules are built and deployed. IoT Edge module projects in Visual Studio and Visual Studio Code include the module.json file. This file has configuration details for the IoT Edge module, like the version and platform used when building the module.

module.json settings

The module.json file has these settings:

Setting	Description
image.repository	The module repository.
image.tag.version	The module version.
image.tag.platforms	A list of supported platforms and their corresponding dockerfile. Each entry is a platform key and dockerfile pair <platform key>:<dockerfile>.
image.buildOptions	Build arguments used when running docker build.
image.contextPath	The context path used when running docker build. By default, it's the current folder of the module.json file. If your Docker build needs files not included in the current folder, like a reference to an external package or project, set contextPath to the root path of all necessary files. Verify the files are copied in the dockerfile.
language	The module programming language.

For example, this module.json file is for a C# IoT Edge module:

{
    "$schema-version": "0.0.1",
    "description": "",
    "image": {
        "repository": "localhost:5000/edgemodule",
        "tag": {
            "version": "0.0.1",
            "platforms": {
                "amd64": "./Dockerfile.amd64", 
                "amd64.debug": "./Dockerfile.amd64.debug",
                "arm32v7": "./Dockerfile.arm32v7",
                "arm32v7.debug": "./Dockerfile.arm32v7.debug",
                "arm64v8": "./Dockerfile.arm64v8",
                "arm64v8.debug": "./Dockerfile.arm64v8.debug",
                "windows-amd64": "./Dockerfile.windows-amd64"
            }
        },
        "buildOptions": ["--add-host=docker:10.180.0.1"],
        "contextPath": "./"
    },
    "language": "csharp"
}

After you build the module, the final image tag combines the version and platform as <repository>:<version>-<platform key>. For this example, the image tag for amd64.debug is localhost:5000/csharpmod:0.0.1-amd64.debug.

Next steps

Understand the requirements and tools for developing IoT Edge modules