remove 'email us for access to Prom-aaS' obstacle

[rade]

https://github.com/weaveworks/frankenstein/blob/master/README.md says

If you are interested in using our hosted Prometheus as a service, please contact help@weave.works.

We need to make it easier for interested folks to access this new part of Weave Cloud, even while it is still in a very fluent state.

[rade]

Some options I can think of...

1. enable access for everyone, i.e. everyone would see the graph icon next to the instance name in the top nav
   • easy
   • there is a distinct lack of explanation about this new feature, the caveats etc
2. enable access for everyone but only show the graph icon when a user has actually sent in some prom data
   • similar to the present "does an instance have probes?" detection
   • easy-ish?
   • this effectively makes the prom ui only accessible to folks who have followed the instructions in the README, thus solving the main problem with 1
3. add some in-service opt-in, with some explanation
   • keeps everything inside the service
   • possibly the way we should generally enable access to experimental features in the future
   • requires a fair bit of design, f/e & b/e code

I am sure there are others.

Of the above, I favour 2, but this rather hinges on whether it can be implemented relatively easily. @tomwilkie @davkal?

[tomwilkie]

This belongs in the frankenstein repo.

[rade]

This belongs in the frankenstein repo.

How so? The bulk of the work likely involves this repo.

[davkal]

I'm in favour of 2 as well. But I'd always show the icon, and then on click check in the backend if there was prom data present. If there was, show prom query UI, if there was not, show help page on how to set up.

@tomwilkie what can the UI query to find out if prom data is available?

Let's not spend too much time on the icon integration, that's done in #853

[tomwilkie]

How so? The bulk of the work likely involves this repo.

The email-us-for-access prompt is in the readme there.

@tomwilkie what can the UI query to find out if prom data is available?

There is no such endpoint.

[rade]

There is no such endpoint.

Would it be hard to add one?

[paulbellamy]

2 seems odd. I'm in favour of 1, with adding some explanation of this feature.

[davkal]

We're gonna do:

• show icon always
• have help page when no data
• have vanilla prom graph UI wrapped with a status banner when data seen

Here are mockups: https://docs.google.com/a/weave.works/presentation/d/1lUL9jAXx8Hi_Fjql9dGB3x7LWnWi4mo18W19hVmcpw4/edit?usp=sharing

[rade]

Here are mockups:

I suggest we split off a phase 0 from the phase 1 in that, which

• adds the endpoint
• removes the feature flag
• displays icon only when the endpoint reports that there are connected proms
• removes the "email us" from https://github.com/weaveworks/prism/blob/master/README.md

Nearly all of that is needed for phase 1, so we are not doing unnecessary extra work. And it resolves the substance of this issue sooner. Incremental improvement, etc, etc.

Any compelling reason not to do that?