Changes to modules are not pulled in automatically

[gruntwork-io]

Changes to modules are not pulled in automatically

[josh-padnick]

I think @abtreece raises a valid improvement or feature we could add. For example, the .terragrunt file could have an option like this:

modules = {
   autoUpdate = true
}

When true, we could follow the method suggested by @brikis98 above. False would be the default, and would represent our current behavior.

[brikis98]

Thanks for filing. This is a limitation of Terraform itself. Perhaps it can be fixed by relying on Git sha1 commit hashes and checking if they changed for each module on each run?

[abtreece]

Perhaps... I'm going to dig into it further. My Go skills are limited at this point, but I am learning and will try to contribute.

[brikis98]

Awesome, thanks :)

[abtreece]

I like ^this^. There is a ref function in the Terraform module source parameter, but adding an option to the terragrunt config would be easier to use and/or an additional fail-safe.

[bwhaley]

Raising this issue from the dead. Not sure I fully understand the feature request here. Is it that Terragrunt will always check the remote to ensure that the code locally matches the code on the remote? E.g. if a module source has ref=foo-bar-branch, and Terragrunt has already downloaded that module at that ref, it currently will not download it again, even if a new commit has been pushed to foo-bar-branch.

If that is indeed the feature request, then --terragrunt-source-update is a reasonable workaround. This will ensure that the contents of the folder are deleted and will force Terragrunt to download again.

Another option is to pin the ref to the actual Git commit sha. Any valid Git reference will work for a module source, including the branch, tag, and sha.

Recommend closing this unless I'm missing something!

[yorinasub17]

The issue is for a specific use case of terragrunt, where the source modules are local path references. In this case, updates to the module source in the terraform module require a reinit as terragrunt auto init won't kick in.

In this situation, --terragrunt-source-update would indeed be a reasonable workaround, and should not be as painful as using a remote source reference given that it is local path copying.

I think it is reasonable to close this given the existence of --terragrunt-source-update, and the fact that modern terragrunt is built around pulling remote references (in which case this isn't really an issue because the underlying terraform modules would not change unless you update the terraform.source attribute in terragrunt.hcl, and that change would trigger auto-init).