[Bugfix/Feature] Fixed slice render staggering on dashboard first load

[Mogball]

• Initial dashboard loading set a random delay (usually 0 to 5 seconds) on slice rendering
• Triggering a dashboard refresh by changing filters or clicking "Refresh" did not do this
• If a slice is indicated in timed_refresh_immune_slices it will not load upon initial rendering

Refreshing the dashboard now will either stagger or not stagger slice rendering, regardless of how it is triggered, and there is the option to disable this and set the stagger interval (in milliseconds) in the dashboard's JSON Metadata: { ... "stagger_refresh": false, "stagger_time": 15000 }

Default value is true and 5 seconds. Staggering is also more deterministic.

[coveralls]

Coverage remained the same at 69.142% when pulling 1c9bbefacc6b9245ba6bec6bab6d20d8ccd71f07 on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[coveralls]

Coverage remained the same at 69.142% when pulling 1c9bbefacc6b9245ba6bec6bab6d20d8ccd71f07 on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[coveralls]

Coverage remained the same at 69.142% when pulling 1c9bbefacc6b9245ba6bec6bab6d20d8ccd71f07 on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[coveralls]

Coverage remained the same at 69.142% when pulling 1c9bbefacc6b9245ba6bec6bab6d20d8ccd71f07 on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[coveralls]

Coverage remained the same at 69.142% when pulling 0d9a97e3ddbccdf1ab07ae406e0dd98d05ced96f on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[coveralls]

Coverage remained the same at 69.142% when pulling 0f84378cd4f88de2c75d0fa2ccf37a0cb7ca7786 on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[coveralls]

Coverage remained the same at 69.142% when pulling 0f84378cd4f88de2c75d0fa2ccf37a0cb7ca7786 on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[coveralls]

Coverage remained the same at 69.142% when pulling 0f84378cd4f88de2c75d0fa2ccf37a0cb7ca7786 on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[coveralls]

Coverage remained the same at 69.142% when pulling c622f9580abbbb85cd4feda85f1f733a44a34a60 on Mogball:mogball/feature/dashboard_loading into e22aecb on apache:master.

[mistercrunch]

These 2 new configuration elements (stagger_refresh, stagger_refresh) need to be documented. Currently the best place for that is faq.rst

[Mogball]

@mistercrunch Added to docs

[coveralls]

Coverage increased (+0.3%) to 69.442% when pulling 963b9cb on Mogball:mogball/feature/dashboard_loading into 6fe93e1 on apache:master.

[coveralls]

Coverage increased (+0.3%) to 69.442% when pulling 963b9cb on Mogball:mogball/feature/dashboard_loading into 6fe93e1 on apache:master.

[coveralls]

Coverage increased (+0.3%) to 69.442% when pulling 963b9cb on Mogball:mogball/feature/dashboard_loading into 6fe93e1 on apache:master.

[mistercrunch]

Wait I didn't realize that there was a 5 * random sec delay by default on first load. I thought [community contributed] startPeriodicRender only applied when auto-refresh mode was on.

We need to remove that delay on the first load, the idea with the delay was to randomize the subsequent refreshes so that if you set it to refresh every 5 minutes, it won't go all reload at once, it's nicer if the slices go randomly over that period.

Do you want take this on as part of this PR since you're already deep into it?

[Mogball]

Alrighty. I'll make changes so that

• Dashboard instantly refreshes: on initial load, when changing dashboard filters, when force refreshing the dashboard
• stagger_refresh and stagger_time will only affect the periodic refreshing

[coveralls]

Coverage remained the same at 69.535% when pulling 268804e on Mogball:mogball/feature/dashboard_loading into 9af34ba on apache:master.

[coveralls]

Coverage remained the same at 69.535% when pulling 268804e on Mogball:mogball/feature/dashboard_loading into 9af34ba on apache:master.

[coveralls]

Coverage remained the same at 69.535% when pulling 268804e on Mogball:mogball/feature/dashboard_loading into 9af34ba on apache:master.

[coveralls]

Coverage remained the same at 69.535% when pulling 268804e on Mogball:mogball/feature/dashboard_loading into 9af34ba on apache:master.

[coveralls]

Coverage remained the same at 69.535% when pulling 268804e on Mogball:mogball/feature/dashboard_loading into 9af34ba on apache:master.

[Mogball]

@mistercrunch Done