Pull existing images to update them to new versions

[kennu]

Apparently there is no way to pull each configured image to update them to latest versions. I frequently do this because I deploy new versions of my apps by pushing new images to a private repository. Currently I have to run "docker pull" manually for each of them.

Could there be a command like:

fig pull [service]

(If there already is a command for this, I missed it while trying to grep the source code and read the docs.)

[aanand]

I've thought about this too. I think my one worry is that if you're using images you've just built/tagged manually, it'll try to pull them and fail. However, I'm not aware of anyone doing that (I mean, that's what build: /path/to/build/dir is for), so it's probably an edge case.

[kennu]

In my case, we're running Fig on a cloud server, and the actual images are built by developers on their own computers. I don't know if this is the usual case..

[sherzberg]

+1

@kennu not sure if its good or not, but this is what we do too. currently I am managing two almost identical fig files. one with build and one with image.

[bfirsh]

+1 fig pull

[bmorton]

+1 for fig pull service or fig update service

Would the maintainers be interested in this if I tried to put something together?

[bfirsh]

@bmorton yeah, that'd be fantastic!

[sublimino]

fig pull would be fantastic. Currently using this (usual regex caveats apply):

for image in $(sed 's/image: \(.*\)/\1/gp;d' fig.yml); do docker pull $image; done

[schainker-digbil]

Can fig up automatically get the latest updates for specified images, too? Then we have both manual and "automatic" ways of handling this.

[bfirsh]

@schainker-digbil I agree that "fig up" should always attempt to create a consistent environment, even if it is slower. Related: #12

[aanand]

I can see auto-pull being a problem when:

1. there's no internet connection
2. the internet connection is bad
3. there's a ton of stuff to download

1 can be worked around by checking for a working connection (or attempting to pull and catching the appropriate error). 2 and 3, I'm less sure about. I don't want to have to wait around to get to work just because someone released a new version of an image I depend on.

It's also worth noting that auto-pull would result in different update semantics for image services than for build services. Even if we automatically build on every invocation of fig up, if there's a cached build then Docker won't attempt to pull the upstream FROM image.

[sublimino]

I concur with @aanand's cache analogy - docker will never retrieve the latest base image unless the cache is invalidated, and as such doesn't create a consistent environment between caches before/after a given image tag.

Perhaps fig up --pull could transparently invoke fig pull, or notify that the cached :latest does not match the remote?

[d11wtq]

I definitely would not want auto-pull behaviour. Our CI updates the tags in the registry. In the same way I don't want my git master to auto-pull just because a colleague pushed new code while I'm in the middle of something, I don't want my docker containers to mysteriously change the next time I do fig up while in the middle of something. fig pull is nice and explicit and has a nice symmetry with the docker client. fig up --pull would be a fine addition too 👍

[schainker-digbil]

@aanand: For #2, maybe you could monitor the connection speed while you download and bail out if it's too slow, and then relaunch the "stale" container? For #3, I it depends whether the user cares about a ton of stuff to download or not? In our deployment, we mostly push small changes once the container is up. Good points, though, those last two cases are "non-trivial".

@sublimino @d11wtq what about fig up --pull warns the user :latest doesn't match remote but applies no changes, and a fig up --pull --force to ignore warnings and do apply changes?

[d11wtq]

I think fig up --pull should just blindly pull the most up to date tag without warning, since that's what you're explicitly asking for. It just making it automatic on fig up and fig run that I don't want.

[schainker-digbil]

@d11wtq +1