Automatically create a live preview for every PR

[hansl]

It might be a firebase server, or AppEngine. I would consider building a docker on Travis as a Part I and then sending that docker to a server as Part 2.

[jelbourn]

One possible approach:

1. Add GitHub hook to remote server when a PR is opened / updated
2. Remote server pulls the PR, builds, copies build output to a directory and serves it.
3. Bot posts to the PR with a link to the preview

Note that any servers being used need to be administered by the Angular team, so any community contribution here would be more about the tooling involved.

[devversion]

So, I'm working on this issue.

The following steps will be executed:

• Waiting for Github Webhooks
• Applies PR patch to a extra branch for the PR (preview/pr-517)
• Builds Distribution with Angular CLI
• Bundles required dependencies into a bundle (accelerates firebase deploy and load time significant)
• Modifies the index.html with a virtual DOM, to use the bundle file.
• Removes unnecessary vendors (e.g ´@angular` - it's now in the bundle)
• Deploys new change to the Firebase Hosting
• Post's link to the PR preview to the PR.

I've already finished this and it's working very well.

I saved a lot of time, by building / enhancing the internal Angular Bot for Material 1 (in progress)

Little Preview of PR #517 (automatically generated)

• https://angular-bot.firebaseapp.com/pr-517/

@jelbourn If you wan't to chat about the implementation or how we should continue, let me know :)

[devversion]

Here is a live preview, how it currently looks like.

It has a build time of ~1-2 minutes (minus wasted time for manually executing the hook).

• Test PR devversion/material2#2

Notice, how the bot posts the link of the automatically built preview. (Message is just temporary)

[jelbourn]

@devversion wow, that was fast.

Bundles required dependencies into a bundle (accelerates firebase deploy and load time significant)

Are you just running npm install on each PR to get the latest clean dependencies?

Overall sounds great. Once you make a PR, I can spin up a new firebase instance and we can simply point the code to that.