Depends_on ignored

[BuckinghamIO]

When using Terraform with the Helmfile provider it completely ignores any depends on requirements.

In my instance I require this as some of my hooks actually setup credentials which are only available once the cluster is created. Since the Helmfile resource always try to generate a diff output regardless of the depends on requirement it fails every time on a fresh install unless I create Terraform and Helmfile seperately.

is there anyway I can work around this?

EDIT: the main cause of this issue is terraform plan also executes helmfile diff without taking into consideration if tiller is even present let alone if the cluster is even present

[mumoshu]

@BuckinghamIO It should generally work. How are you providing KUBECONFIG envvar or kubeconfig_path attribute to your helmfile_release_set resource? The release set resource is programmed to skip running helmfile-diff when kubeconfig_path is empty, because it is set to empty by terraform plan.

A working example is https://github.com/mumoshu/terraform-provider-eksctl/blob/master/examples/productionsetup-alb/testdata/01-bootstrap/main.tf#L155. In this example, terraform plan does work even before creating the eksctl_cluster, because the helmfile provider skips running helmfile-diff when KUBECONFIG is empty.

To be clear, even if it is declared as KUBECONFIG = eksctl_cluster.blue.kubeconfig_path, terraform plan evaluates it to KUBECONFIG = "" before creating the dependent eksctl_cluster. But the helmfile provider skips running helmfile-diff when it is empty, plan succeeds and works as expected.

[mumoshu]

In other words and from a developer's perspective, it is Terraform that ignores depends_on on plan, not the provider. So we need to understand every real-world use-case and implenment a workaround for each so that the provider "looks" like understanding depends_on, even if Terraform doesn't support it.

[mumoshu]

@BuckinghamIO #42 may also fix your issue if this was due to that

[danil-fomichev]

@mumoshu here is a use-case example.

We would like to generate environment.yaml file with values imported from another modules and only after that run the helmfile_release_set resource. Right now we cannot do this because the provider runs "helmfile diff" and it fails because the file doesn't exist.

[mumoshu]

@danil-fomichev How is environment.yaml used by your helmfile_release_set? An example helmfile_release_set definition would help!

[danil-fomichev]

@mumoshu it is included from helmfile.yaml:

bases:
- environment.yaml

obviously it must be generated before we run "helmfile diff".

The name of environment is specified in helmfile_release_set definition.

[mumoshu]

@danil-fomichev Gotcha! Thanks for clarifying. AFAIK, there's no way to make some terraform resource's "plan" operation optional depending on condition. #38 (comment)

So the only way would be to enhance the provider to support something like skip_diff_on_missing_files = ["path/to/environment.yaml"] so that the provider can skip helmfile-diff before the files are generated somehow.

WDYT?

[danil-fomichev]

@mumoshu great idea! And thank you!

[mumoshu]

@danil-fomichev Thanks for confirming! I'll give it a try

[mumoshu]

@BuckinghamIO Does the planned feature above #38 (comment) look like to work for your use-case, too?

[mumoshu]

@danil-fomichev @BuckinghamIO skip_diff_on_missing_files is added since v0.10.0. Would you mind giving it a try?

[danil-fomichev]

@mumoshu Thank you so much! When approximately do you plan to publish it to registry.terraform.io?

[mumoshu]

@danil-fomichev It should be available soon :) registry.terraform.io automatically syncs github releases so there should be nothing blocking that process on my end.

[danil-fomichev]

@mumoshu unfortunately it doesn't work as expected.

resource "helmfile_release_set" "infra" {
  depends_on            = [local_file.environment_file]
  working_directory     = var.helmfile_path
  environment           = var.environment.name
  kubeconfig            = var.kubeconfg_path
  environment_variables = local.environment_variables
  skip_diff_on_missing_files = [
    local_file.environment_file
  ]
}

it still runs 'helm diff' during 'terraform plan' and fails with error.

[danil-fomichev]

It works when I set absolute path to the file instead of 'local_file.environment_file'. Not very nice looking code but it works.

Thanks!

[mumoshu]

@danil-fomichev Thanks for the feedback! I'll definitely enahnce it to work with relative paths. Stay tuned.

[mumoshu]

@danil-fomichev Since v0.10.1, it automatically coverts relative paths to absolute paths. Would you mind trying?

If it doesn't work as expected, try running terraform with TF_LOG=TRACE terraform plan so that you can see logs added in b24131f#diff-5cd325f86c36ad7da723fd859369712f88fe899ef97a4f3b286cda8f8625c6a9R12 for debugging