[Issue] Support passing build-arg to docker builds

[aaronpowell]

When deploying apps that are within a container, such as Container Apps, there can be scenarios where you need to provide build-time variables to the Dockerfile. An example of this I described in this issue comment, but there are other reasons you may need an environment variable to trigger different aspects of the container build.

Looking at the Docker build function here:

azure-dev/cli/azd/pkg/tools/docker/docker.go

Lines 43 to 60 in 037e763

	func (d *Docker) Build(
	ctx context.Context,
	cwd string,
	dockerFilePath string,
	platform string,
	buildContext string,
	) (string, error) {
	if strings.TrimSpace(platform) == "" {
	platform = "amd64"
	}
	res, err := d.executeCommand(ctx, cwd, "build", "-q", "-f", dockerFilePath, "--platform", platform, buildContext)
	if err != nil {
	return "", fmt.Errorf("building image: %s: %w", res.String(), err)
	}
	return strings.TrimSpace(res.Stdout), nil
	}

There's no way to provide a build-arg flag to the docker build command. I suggest we expand the docker.properties part the azure.yaml schema (

azure-dev/schemas/v1.0/azure.yaml.json

Lines 110 to 139 in 037e763

	"docker": {
	"type": "object",
	"description": "This is only applicable when `host` is `containerapp`",
	"additionalProperties": false,
	"properties": {
	"path": {
	"type": "string",
	"title": "The path to the Dockerfile",
	"description": "Path to the Dockerfile is relative to your service",
	"default": "./Dockerfile"
	},
	"context": {
	"type": "string",
	"title": "The docker build context",
	"description": "When specified overrides the default context",
	"default": "."
	},
	"platform": {
	"type": "string",
	"title": "The platform target",
	"default": "amd64"
	},
	"tag": {
	"type": "string",
	"title": "The tag that will be applied to the built container image.",
	"description": "If omitted, a unique tag will be generated based on the format: {appName}/{serviceName}-{environmentName}:azdev-deploy-{unix time (seconds)}. Use environment variable substitution to generate unique tags for a given release. For example, myapp/myimage:${DOCKER_IMAGE_TAG}."
	}
	}
	}
	},

) so that we can provide build-args as desired.

[jongio]

Great idea! Thanks for the request.

[weikanglim]

We should consider how this plays well with #1810

Also, do we expect envsubt to work with this parameter configuration? Or should the configuration be configurable via env variables?

[aaronpowell]

We should consider how this plays well with #1810

Sure. I'll have a read of #1810 and add thoughts.

Also, do we expect envsubt to work with this parameter configuration? Or should the configuration be configurable via env variables?

I think we should support substitution of environment variables, both from a system level and from the azd output. I described a particular scenario in #121 (comment) in which I wanted to take the output from one service and use it in another via buildArgs, so that's my end goal here.

[savannahostrowski]

Is this now complete via #2266 ?