RudderVirt

#Previewing a module

A preview is your own private copy of a module, running the same image your students would get. It exists so you can walk through a module yourself before you put it in front of a class, and so module authors can check a build before promoting it.

Previewing is available to anyone whose organization can see the module: the organization that built it, an organization it was shared with, and any organization at all for a public module.

#Starting one

There are two ways in, and both do the same thing:

  • On the module page, use the Preview button in the action bar.
  • In the module library, open a module row's menu and choose Preview. You will land on the module page, where the preview appears once it is ready.

Provisioning takes a minute or so. The button becomes Preview provisioning while that happens, then Open preview, which opens the VM console in the browser.

If the Preview option is greyed out, it is for one of two reasons. Either the module has no stable build in your organization's deployment zone yet — the same condition that stops you releasing it to a class, and nothing can be previewed until one is promoted — or your organization has bought no capacity yet. Previewing needs at least one virt on your account, or at least one VM Slot on your subscription. The button says which applies when you hover it.

#Which build you get

Your preview runs your zone's stable build of the module: exactly what students receive when you release it. You do not choose the build, and you cannot preview work the author has not promoted.

Module authors and maintainers get more. From the Builds tab, or from an individual build's page, they can preview any succeeded build, which is how a build gets checked before it becomes stable.

If the author promotes a newer build while your preview is running, your next Preview click re-points the clone at it. That resets the VM, so anything you did in the old one is gone. You will be asked to confirm.

#What it costs, and how it goes away

A preview is free to run. It spends no virts and holds no VM Slot, so you can try a module while every slot you own is committed to live classes, and being at your limit never stops you evaluating something.

What it does require is that you have bought something: an organization with no virts and no subscribed VM Slots cannot start a preview. Holding capacity is enough — previewing never consumes it.

What pays for that is a short leash:

  • A preview runs for one hour, measured from when you started it. The module page shows the time remaining next to Open preview. At the hour the console stops opening and the clone is deleted, whether or not you were using it.
  • Re-pointing a preview at a newer stable build, or resetting it from the Builds tab, gives you a fresh hour.
  • Your organization gets one preview at a time, across all modules. Starting one while another module's preview is running is refused, and names the module to destroy first. Yours is still separate from the author's and from every other organization's.

Use Destroy preview on the module page as soon as you are done, rather than waiting out the hour, so you can preview something else. Nothing is lost by letting it expire on its own.

#Grading

Running the module's grader against a preview is a module-authoring feature, limited to the organization that owns the module and to maintainers it has shared editing rights with. The grade breakdown includes the commands the grader runs and the answers it expects, which is not something to hand to everyone who can run the module.

You can still work through a preview exactly as a student would; you just will not see a score for it.