Arvados

Draft for discussion

Another possibility

Putting up my own idea. Apologies for my chicken scratch. Here are the key things I think are relevant:

• We present the lifecycle as basically linear, and then throughout that process there are a series of off-ramps that all lead to the container request having state=Final. I think this lends itself well to a two-column presentation, where the first column represents the full normal lifecycle and then the second column are the end states that the different off-ramps take you to.
• Boxes represent object state, arrows represent different actors changing those objects' state. Boxes document what object is changing (container request and/or container) and the key field changes that occurred from the action. Arrows document both who is acting on an object (user, API server independently, Crunch) and what the change is.
• IMO the two-layer presentation of container request state and container state in Tom's suggestion is a little too clever and dense. I would rather have each box document both the state of the container request and its associated container (if any).
• I used a lot of abbreviations for space. We should spell everything out. CR = container request. c_uuid = container_uuid. "User cancels CR" = User updates container request with priority=0. My descriptions of the transitions between Queued→Locked→Running might be a little off, please correct, I more wanted to get the structure out than exactly right.
• We could highlight other key fields that change like log_uuid, output_uuid, etc.
• I forgot to draw an arrow for "Container runs to completion," oops.
• We could probably add judicious color outlines to distinguish end states with no container, cancelled container, failed container, and successful container.

I gave up trying to coerce the graphviz layout. Using color to indicate the end states seems to work OK though.

If you like this version I can just tack it onto the branch, let me know.

Applied in changeset arvados|e75f2cd097eb9c8e541576fadce46e09c51c7dab.