Update chart dependencies before installing

[squaremo]

This addresses #1278, for the "alpha" series (i.e., not for #1382). It simply calls helm dep build in the chart directory, when installing or upgrading a release.

Note that it bakes in a repositories.yaml file (which specifies the repo URLs, and is necessary for the helm commands to function). This file specifies only the conventional "stable" repo. We will need to figure out how to allow other repos to be specified; it is not quite good enough to mount your own file, since it lives in a directory helm wants to write to (and the mount would mean it's read-only).

[squaremo]

I need to make sure this can cover a couple of scenarios aside from the bare basics:

Can you set it up to use a repo other than stable?

This will probably mean mounting a repositories.yaml file; but,

• those tend to have local paths in them
• .. and possibly refer to certificates which would also need to be present
• .. and, Helm really wants this file to be in the same directory as where it's downloading charts, but if you're mounting it from a volume, it'll be read-only

How do you provide credentials for the repo?

Credentials get put in the repositories.yaml file; so again, if you want to supply credentials, you'd have to mount that file from a secret, with the problems as above.

[squaremo]

Can you set it up to use a repo other than stable?

This will probably mean mounting a repositories.yaml file; but,

• those tend to have local paths in them
• .. and possibly refer to certificates which would also need to be present
• .. and, Helm really wants this file to be in the same directory as where it's downloading charts, but if you're mounting it from a volume, it'll be read-only

How do you provide credentials for the repo?

Credentials get put in the repositories.yaml file; so again, if you want to supply credentials, you'd have to mount that file from a secret, with the problems as above.

I've tried both of these things (in one go). You can mount a repositories.yaml file into the expected location $HELM_HOME/repository/repositories.yaml, so long as you:

• mount another, writable volume at $HELM_HOME/repository/cache/, so helm has a writable directory in which to put its cached things, and
• adapt the repositories.yaml file, so that each entry has a field cache pointing at the expected location of the index cache.

On that second thing: Helm seems to expect a specific value in the cache field, that is $HELM_HOME/repository/cache/$repo-index.yaml. If you exclude the cache field, helm tries to use $HELM_HOME/repository/cache as a file while updating the repo index, and breaks because it's a directory. If you provide something other than the expected value, it breaks while releasing the chart because there's no file at the expected location. (We use a recent revision of the helm go package, but an older version of the helm binary, so perhaps the differing expectations are due to that mismatch).

[squaremo]

I could do the dependency update in code to try and work around the oddnesses, but it would be a drastic step, because the helm go library also assumes the repositories.yaml, index files, and cache are inextricably tied (they all get calculated relative to a value helmhome.Home). It would involve reimplementing all the bits that make that assumption :-(

[squaremo]

I've pushed the image quay.io/squaremo/helm-operator:pr-1450 for anyone who wants to try this out.

[skurtzemann]

I've pushed the image quay.io/squaremo/helm-operator:pr-1450 for anyone who wants to try this out.

I've try your image and requirements are correctly installed 👍

• https://github.com/skurtzemann/gitops-helm/tree/master/charts/podinfo

[stefanprodan]

LGTM tested with public repos