feat: add saml client installation provider

[Filirom1]

Hello,

I need to retrieve the SAML installation XML to inject it in AWS SAML Provider

resource "keycloak_realm" "realm" {
    realm   = "my-realm"
    enabled = true
}

resource "keycloak_saml_client" "saml_client" {
    realm_id                = "${keycloak_realm.realm.id}"
    client_id               = "test-saml-client"
    name                    = "test-saml-client"

    sign_documents          = false
    sign_assertions         = true
    include_authn_statement = true

    signing_certificate = "${file("saml-cert.pem")}"
    signing_private_key = "${file("saml-key.pem")}"
}

data "keycloak_saml_client_installation_provider" "saml_idp_descriptor" {
  realm_id    = "${keycloak_realm.realm.id}"
  client_id   = "${keycloak_saml_client.saml_client}"
  provider_id = "saml-idp-descriptor"
}

resource "aws_iam_saml_provider" "default" {
  name                   = "myprovider"
  saml_metadata_document = data.keycloak_saml_client_installation_provider.saml_idp_descriptor.value
}

I started this Pull Request that is working, but I will need help if you need tests or refactoring because I am not fluent in golang yet :-)

Cheers
Romain

[mrparkers]

Hey @Filirom1, thanks for the PR!

I think the code you've submitted looks good so far. I really like the example you posted in this PR, that's a good use case for this data source. If you'd like, you could include that example in the docs to show off a real use case for this.

I've never personally used the "Installation" tab for a SAML client before, but based on the code you've submitted, it looks like you're expecting an XML document to be returned in the value attribute. I think a good test for this data source would create a realm, a saml client, and a saml installation provider data source (just like your example), and grab the value attribute from the data source and use golang's xml package to parse it. You'll have to create a basic struct with xml tags, but you don't have to include the entire structure of the xml payload if you don't want to. All I want to assert is that the value attribute is an xml document.

You can look at examples for parsing xml in the xml package godoc: https://golang.org/pkg/encoding/xml/. Feel free to model your test similarly to the other data source tests.

If you have any specific questions about any of this please feel free to let me know. Thanks!

[Filirom1]

Is it OK for you @mrparkers ?

[mrparkers]

LGTM, thanks for the PR!

[jurgen-weber-deltatre]

so for setting up a SAML client for AWS...

signing_certificate = "${file("saml-cert.pem")}"

signing_private_key = "${file("saml-key.pem")}"

what are these files? Where do I get them?