Improve scope documentation for amp-install-serviceworker and amp-web-push scopes

[westonruter]

What's the issue?

Normally when wanting to install a service worker, the way to do so is to use the aptly-named amp-install-serviceworker component.

However, if wanting to then add push notifications, the amp-web-push component needs to be used.

This introduces a problem because the amp-web-push component also takes the responsibility of installing a service worker (apparently). Because only one service worker can be active on a given page, this introduces a conflict.

This being said, in testing if I add both components to the page, it doesn't seem to result in the service worker attempting to be installed twice. In fact, only the service worker referenced in amp-install-serviceworker is being added, even when I put <amp-web-push> before <amp-install-serviceworker>. I'm not seeing <amp-web-push> install any service worker at all, so maybe I am not correctly understanding how it is supposed to work. However, if it is supposed to install a service worker it could create major confusions when a user tries to supply a service worker script that is specific to push notifications on <amp-web-push> but another script entirely for <amp-install-serviceworker>. This should get raised by the component as a user error.

Also, ideally the amp-web-push component would allow omission of the service-worker-url attribute if there is an <amp-install-serviceworker> element on the page. This would also allow amp-web-push to take advantage of the capabilities of amp-install-serviceworker, such as installing the origin service worker while accessing a page loaded from an AMP Cache.

All of this to say, I am not clear if there is actually a conflict. But since the documentation for the components does not refer to each other, it is not clear if they can work together. If not, they should. And the docs should be updated to clarify.

How do we reproduce the issue?

Include both amp-service-worker and amp-web-push on a page.

[westonruter]

It turns out that this is not a conflict, as long as the scope for the amp-web-push does not conflict with the scope of the service worker that is expected to control the requests of the page.

[westonruter]

I think the main thing needed here is to improve documentation, to make it clear how amp-web-push and amp-install-serviceworker can be used together, especially in regards to making the scopes distinct.

[rgomezp]

I've encountered some of our users seeing this exact issue. They have their own service worker but also want to use amp-web-push. To make everything work, they have to put the notifications SW on a different scope, say /push. This was all found by trial and error so it would be helpful to make a note on the documentation page for amp-web-push of how these two work together.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.

[rgomezp]

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