How to set global tags in Pulumi Azure Native

In a stack specific settings file (i.e. Pulumi.dev.yaml), if location is set (i.e. azure-native:location) then resource group location is set automatically and location for resources is derived from resource group location. Now I am trying to apply common tag for all resources i.e. CreatedBy: Pulumi. Is there any way to set common/global tags, similar to azure-native:location in settings file (Pulumi.dev.yaml) ?

Expected: both location and tags will be set from Pulumi.dev.yaml

config:
  azure-native:location: japaneast
  azure-native:tags:
    CreatedBy: Pulumi

var mainRgArgs = config.RequireObject<JsonElement>(KEY_RESOURCE_GROUP_ARGS);
var mainRgName = mainRgArgs.GetProperty(RESOURCE_GROUP_NAME).GetString()!;

var mainRg = new ResourceGroup(RESOURCE_GROUP_MAIN, new ResourceGroupArgs
{
    ResourceGroupName = mainRgName
    //Location = 
    //Tags = 
});

Solution

It isn't possible to set the tags automatically, because tags aren't a required API property.

The reason location is a provider argument is because every resource requires a location when it's created. That isn't true for tags.

However, it is possible to automatically add tags to resources that are taggable (which isn't all resources) using a transformation

Transformations allow you to inject properties into every resource, regardless of whether you've set that value on your resource explicitly. You will however have to set a list of taggable resources, because not every Azure resource is taggable.

A function which will register tags on resources will look something like this:

export function registerAutoTags(autoTags: Record<string, string>): void {
    pulumi.runtime.registerStackTransformation((args) => {
        if (isTaggable(args.type)) {
            args.props["tags"] = { ...args.props["tags"], ...autoTags };
            return { props: args.props, opts: args.opts };
        }
        return undefined;
    });
}

and then you can use those tags by calling the function:

registerAutoTags({
    "user:Project": pulumi.getProject(),
    "user:Stack": pulumi.getStack(),
    "user:Cost Center": config.require("costCenter"),
});

There's more information on this (albeit for AWS, not Azure) here. You can find a list of Azure resources that are support tags here