Function getFeaturesBuildOptions

src/spec-node/containerFeatures.ts:227–361

(params: DockerResolverParameters, devContainerConfig: SubstitutedConfig<DevContainerConfig>, featuresConfig: FeaturesConfig, baseName: string, imageBuildInfo: ImageBuildInfo, composeServiceUser: string | undefined)

}

async function getFeaturesBuildOptions(params: DockerResolverParameters, devContainerConfig: SubstitutedConfig<DevContainerConfig>, featuresConfig: FeaturesConfig, baseName: string, imageBuildInfo: ImageBuildInfo, composeServiceUser: string | undefined): Promise<ImageBuildOptions | undefined> {
	const { common } = params;
	const { cliHost, output } = common;
	const { dstFolder } = featuresConfig;

	if (!dstFolder || dstFolder === '') {
		output.write('dstFolder is undefined or empty in addContainerFeatures', LogLevel.Error);
		return undefined;
	}

	// With Buildkit (0.8.0 or later), we can supply an additional build context to provide access to
	// the container-features content.
	// For non-Buildkit, we build a temporary image to hold the container-features content in a way
	// that is accessible from the docker build for non-BuiltKit builds
	// TODO generate an image name that is specific to this dev container?
	const buildKitVersionParsed = params.buildKitVersion?.versionMatch ? parseVersion(params.buildKitVersion.versionMatch) : undefined;
	const minRequiredVersion = [0, 8, 0];
	const useBuildKitBuildContexts = buildKitVersionParsed ? !isEarlierVersion(buildKitVersionParsed, minRequiredVersion) : false;
	const buildContentImageName = 'dev_container_feature_content_temp';
	const disableSELinuxLabels = useBuildKitBuildContexts && await isUsingSELinuxLabels(params);
    // Access Docker engine version
    const dockerEngineVersionParsed = params.dockerEngineVersion?.versionMatch ? parseVersion(params.dockerEngineVersion.versionMatch) : undefined;
    const minDockerEngineVersion = [23, 0, 0];
    const skipDefaultSyntax = dockerEngineVersionParsed ? !isEarlierVersion(dockerEngineVersionParsed, minDockerEngineVersion) : false;
	const omitPropertyOverride = params.common.skipPersistingCustomizationsFromFeatures ? ['customizations'] : [];
	const imageMetadata = getDevcontainerMetadata(imageBuildInfo.metadata, devContainerConfig, featuresConfig, omitPropertyOverride, getOmitDevcontainerPropertyOverride(params.common));
	const { containerUser, remoteUser } = findContainerUsers(imageMetadata, composeServiceUser, imageBuildInfo.user);
	const builtinVariables = [
		`_CONTAINER_USER=${containerUser}`,
		`_REMOTE_USER=${remoteUser}`,
	];
	const envPath = cliHost.path.join(dstFolder, 'devcontainer-features.builtin.env');
	await cliHost.writeFile(envPath, Buffer.from(builtinVariables.join('\n') + '\n'));

	// When copying via buildkit, the content is accessed via '.' (i.e. in the context root)
	// When copying via temp image, the content is in '/tmp/build-features'
	const contentSourceRootPath = useBuildKitBuildContexts ? '.' : '/tmp/build-features/';
	const dockerfile = getContainerFeaturesBaseDockerFile(contentSourceRootPath)
		.replace('#{nonBuildKitFeatureContentFallback}', useBuildKitBuildContexts ? '' : `FROM ${buildContentImageName} as dev_containers_feature_content_source`)
		.replace('#{featureLayer}', getFeatureLayers(featuresConfig, containerUser, remoteUser, useBuildKitBuildContexts, contentSourceRootPath))
		.replace('#{containerEnv}', generateContainerEnvsV1(featuresConfig))
		.replace('#{devcontainerMetadata}', getDevcontainerMetadataLabel(imageMetadata))
		.replace('#{containerEnvMetadata}', generateContainerEnvs(devContainerConfig.config.containerEnv, true))
		;
    const syntax = imageBuildInfo.dockerfile?.preamble.directives.syntax;
    const omitSyntaxDirective = common.omitSyntaxDirective; // Can be removed when https://github.com/moby/buildkit/issues/4556 is fixed
    const dockerfilePrefixContent = `${omitSyntaxDirective ? '' :
        skipDefaultSyntax ? (syntax ? `# syntax=${syntax}` : '') :
        useBuildKitBuildContexts && !(imageBuildInfo.dockerfile && supportsBuildContexts(imageBuildInfo.dockerfile)) ? '# syntax=docker/dockerfile:1.4' :
        syntax ? `# syntax=${syntax}` : ''}
ARG _DEV_CONTAINERS_BASE_IMAGE=placeholder
`;

	// Build devcontainer-features.env and devcontainer-features-install.sh file(s) for each features source folder
	for await (const fSet of featuresConfig.featureSets) {
		if (fSet.internalVersion === '2')
		{
			for await (const fe of fSet.features) {