azuredns: allow oidc authentication

[pchanvallon]

Hello,

Here is the implementation for the OIDC authentication support (fixes #2027).

I was able to test the integration with GitHub actions workflows, but not with Terraform cloud.
@stmcx, can you try that this is also working in your use case ?

Thanks.

[stmcx]

Thanks @pchanvallon

Rebuilt Terraform ACME provider with replace github.com/go-acme/lego/v4 v4.14.2 => github.com/pchanvallon/lego/v4 v4.0.0-20231018073353-c97089b94e14

Did not work and got 401 at first

Then included AZURE_AUTH_METHOD="oidc" and it worked!

* (Terraform Cloud exports "ARM_USE_OIDC" = "true" instead but that is okay)

resource "acme_certificate" "certificate" {
  account_key_pem              = acme_registration.registration.account_key_pem
  common_name                  = var.certificate_common_name
  subject_alternative_names    = []
  disable_complete_propagation = true
  dns_challenge {
    provider = "azuredns"
    config = {
      AZURE_RESOURCE_GROUP = var.certificate_dns_challenge_azure_resource_group_name
      AZURE_AUTH_METHOD="oidc"
    }
  }
}

Also, I added these here to the provider since Terraform Cloud exports them as ARM rather than AZURE. I guess the provider maintainers will know more.

"ARM_OIDC_REQUEST_TOKEN":   "AZURE_OIDC_REQUEST_TOKEN",
"ARM_OIDC_REQUEST_URL":     "AZURE_OIDC_REQUEST_URL",
"ARM_OIDC_TOKEN":           "AZURE_OIDC_TOKEN",
"ARM_OIDC_TOKEN_FILE_PATH": "AZURE_OIDC_TOKEN_FILE_PATH",

[pchanvallon]

Hello @stmcx,
Thank you for your feedback.
Yes we will have to request this change in acme TF provider after the lib update to finalize the integration.

[ldez]

LGTM