Track app usage

[joelanman]

UPDATE

I had misunderstood custom dimensions, and we should use them to track operating system, node version, prototype kit version

https://docs.google.com/document/d/13or0ac7H8TdfWfMSt8xnsGgOuTV8jp7CuEtPa6qcP9U/edit#

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This work adds opt-in tracking of app usage, using Google Analytics.

It asks for user's permission when first run.

The app then records the user's answer in usage-data-config.js.

If the answer was yes:

It also records a unique user ID in the same file.

It sends an Event to Google Analytics, with:

• Category: 'Start'
• Action: the version of the prototype kit
• Value: the operating system type (eg Windows) and version

I've refactored start.js slightly into a series of functions, this makes it a lot easier to handle the correct flow, based on whether the user is opted in or out.

Known issues

• Not tracking Node version
• The prompt is a bit ugly and needs @amyhupe to check the text
• I think we need a documentation page in the kit to tell people exactly what usage data is recorded, possibly linked to from the prompt

Screens

When recorded in GA, the event looks like this:

[joelanman]

@hannalaakso The data recorded is documented here: https://github.com/alphagov/govuk-prototype-kit-private-beta/blob/d8b51e8a92fce5a231370ddf1c9b6f0f995c385e/docs/documentation/usage-data.md

Nice point about reminding people every start, I'll look into that.

[joelanman]

On reviewing this with @alex-ju, I'm not sure the Google Analytics approach can work.

We want to know for example, what % of our users are on Windows. GA does this with Dimensions, which I don't think we can use (custom dimensions are managed by hand, and only have 200 different values).

GA Events (the approach taken in this PR) are not reported on as above. They are reported on as Total events, or Unique events. Either one one show a user starting the kit twice on Windows to have 2 events, and a user starting once on OSX to have 1. This does not give us the data we need.

[NickColley]

Would this stop heroku from deploying the prototype kit since it could get stuck on this question?

[joelanman]

@nickcolley it's a good question, but Heroku doesn't run npm start - it runs procfile instead

[alex-ju]

Updated with using custom dimensions for storing persistent data (Operating System, Prototype Kit Version and Node Version).

[alex-ju]

Updated with using custom dimensions for storing persistent data (Operating System, Prototype Kit Version and Node Version).

Refactored the code. @nickcolley can you take a look when you have time (no pressure)?

[alex-ju]

@nickcolley thanks for the review. tried to address your comments. please let me know if you feel it's good to go or you have any concerns.

[NickColley]

@alex-ju looks great 👍

[joelanman]

Please don't merge while it has my test GA code on it :)

[alex-ju]

@joelanman I'm aware. We can update the tracking code tomorrow. It's up to you when's the right time to merge it, since you opened this PR, just trying to make we have it prepared.

[alex-ju]

@joelanman updated the tracking code. Looking at the Real-time events seems to be tracking well. I'll check again in a few minutes in the Event section to make sure they're stored correctly.

Updated: records well! good to be merged from my side

[alex-ju]

@joelanman thanks for the review! updated.

[joelanman]

@alex-ju it looks like checkFiles still happens after the require I highlighted?

[edwardhorsford]

It might be worth storing the date the user accepted the opt-in. Might be useful if you ever want to decide whether to send a new opt-in request.

[joelanman]

@edwardhorsford I think thats a good idea, but I think we can add it later. For now the file created date should be ok. It raises the question of whether the 'permission proof' living with the user is sufficient. If they ever lost it there would be no proof. I wonder whether in this case we could prove that data is only sent if a user explicitly opts in.

[alex-ju]

@nickcolley, can you give us a hand with the final review? I'm aware you already approved, but there were some small changes since then.