progress: display vertex status name

[jedevc]

So, it seems that VertexStatus.Name isn't actually used anywhere. Originally, I was attempting to try and update the display name for a vertex status, thinking that Name would be the way to go, but that's not plumbed through in the same way.

I'm not quite sure what the original intention of Name was, but it appears like it was probably something like determining how this would get displayed? The issue is, that over time, the ID field for vertex status has been the thing to display (as a name), and isn't entirely used purely as an identifier.

The Name field gets populated (by setting .Action) by the local file transfers, so taking a change like this could mean that progress on older clients would change, so maybe the safest option would be doing a protobuf field number bump on .Name (since it doesn't appear used anywhere client-side as far as I can tell 🤔).

@sipsma I know you worked a lot on progress things, so maybe you have some insight? I poked around to see how dagger handles this and found this similar kind of remapping: https://github.com/dagger/dagger/blob/35da30bbd9452e16f7e68f3d4fdea93a5c3ec2e2/core/bk2progrock.go#L64.

[vito]

Chiming in as the one that did the remapping in Dagger/Progrock. I was also confused when I saw there was both an ID and a Name, and Name never seemed to be used, but ID seemed to be used like a Name.

Do we need both? It sounds OK in theory, for the same reason that vertices have an ID and a name, but in practice nothing ever keys on a status ID independently of a vertex, and I don't think you'd ever have duplicate names within a vertex, so having both just seems like cruft to me. But maybe I'm missing something.

[jedevc]

We don't need both at the moment - however, if we want to be able to change the Name on a VertexStatus during the run, we'd need both. For example, say you want to change a message to say "extracting" instead of "downloading". We'd need some stable way to refer to that VertexStatus so as to change the name, we can do this already with the Vertex.Digest for vertices, but there's no corresponding way to do it for a VertexStatus (without the ID).

[vito]

@jedevc Playing devil's advocate: wouldn't it be better to create a new status instead of replacing the name on an old one? That way you can distinguish between the "downloading" and "extracting" duration.

Your point definitely stands if there's still some reason to update the name though. 👍

[jedevc]

@vito you're definitely not wrong 😄 Though then, you have to have two separate statuses ( taking up two lines), even if it's "one operation".

e.g. imagine downloading and unpacking a set of artifacts, or layers in an image, etc - having to have double of all of those is a bit tricky, and then takes up a lot more space than wanted.

[jedevc]

Did some more updates for this - TL;DR, I think we should completely get rid of the old progress.Status.Action property (regardless of whether we take this PR) - they're not used to display anything in the progress UI, and seem to be left over from some previous refactor. I've split this removal out into 985b247.

I've then added a new Name property in (with a different proto id), that we can use to actually be able to change the vertex display. This is what we can use to change VertexStatuses displays - for example, to change from "downloading" to "extracting" in a per-layer view.

With this change, we could change:

 => resolve image config for docker.io/docker/dockerfile:1                                                                                                   5.1s
 => docker-image://docker.io/docker/dockerfile:1@sha256:ac85f380a63b13dfcefa89046420e1781752bab202122f8f50032edf31be0021                                     0.9s
 => => resolve docker.io/docker/dockerfile:1@sha256:ac85f380a63b13dfcefa89046420e1781752bab202122f8f50032edf31be0021                                         0.0s
 => => sha256:9d9c93f4b00be908ab694a4df732570bced3b8a96b7515d70ff93402179ad232 11.80MB / 11.80MB                                                             0.7s
 => => extracting sha256:9d9c93f4b00be908ab694a4df732570bced3b8a96b7515d70ff93402179ad232                                                                    0.1s
 => [internal] load metadata for docker.io/library/ubuntu:20.04                                                                                              1.3s
 => [1/4] FROM docker.io/library/ubuntu:20.04@sha256:33a5cc25d22c45900796a1aca487ad7a7cb09f09ea00b779e3b2026b4fc2faba                                        1.8s
 => => resolve docker.io/library/ubuntu:20.04@sha256:33a5cc25d22c45900796a1aca487ad7a7cb09f09ea00b779e3b2026b4fc2faba                                        0.0s
 => => sha256:edaedc954fb53f42a7754a6e2d1b57f091bc9b11063bc445c2e325ea448f8f68 27.51MB / 27.51MB                                                             1.1s
 => => extracting sha256:edaedc954fb53f42a7754a6e2d1b57f091bc9b11063bc445c2e325ea448f8f68                                                                    0.5s

into

 => resolve image config for docker.io/docker/dockerfile:1                                                                                                   5.1s
 => docker-image://docker.io/docker/dockerfile:1@sha256:ac85f380a63b13dfcefa89046420e1781752bab202122f8f50032edf31be0021                                     0.9s
 => => resolve docker.io/docker/dockerfile:1@sha256:ac85f380a63b13dfcefa89046420e1781752bab202122f8f50032edf31be0021                                         0.0s
 => => done sha256:9d9c93f4b00be908ab694a4df732570bced3b8a96b7515d70ff93402179ad232 11.80MB / 11.80MB                                                        0.7s
 => [internal] load metadata for docker.io/library/ubuntu:20.04                                                                                              1.3s
 => [1/4] FROM docker.io/library/ubuntu:20.04@sha256:33a5cc25d22c45900796a1aca487ad7a7cb09f09ea00b779e3b2026b4fc2faba                                        1.8s
 => => resolve docker.io/library/ubuntu:20.04@sha256:33a5cc25d22c45900796a1aca487ad7a7cb09f09ea00b779e3b2026b4fc2faba                                        0.0s
 => => done sha256:edaedc954fb53f42a7754a6e2d1b57f091bc9b11063bc445c2e325ea448f8f68 27.51MB / 27.51MB                                                        1.1s

As a layer moves between "downloading", "extracting" and "done" stages, we can change the message. This halves the number of lines needed to display layer downloads, which could be incredibly useful for large builds.