Avoid specifying publication hrefs for distributions

Pulp hrefs are not very easy to work with, and aren't known up front. Use the
repository name and version to lookup a matching publication when distributing.

Author: markgoddard

roles/pulp_distribution/README.md

@@ -29,10 +29,11 @@ Example playbook
       pulp_distribution_rpm:
         - name: centos-baseos
           base_path: centos-baseos
-          publication:
+          repository: centos-baseos
           state: present
         - name: centos-appstream
           base_path: centos-appstream
-          publication:
+          repository: centos-appstream
+          version: 2
           state: present
 ```

roles/pulp_distribution/tasks/rpm.yml

@@ -1,12 +1,35 @@
 ---
+- name: Query repositories
+  pulp.squeezer.rpm_repository:
+    pulp_url: "{{ pulp_url }}"
+    username: "{{ pulp_username }}"
+    password: "{{ pulp_password }}"
+    validate_certs: "{{ pulp_validate_certs | bool }}"
+  register: pulp_repos_list
+
+- name: Query publications
+  pulp.squeezer.rpm_publication:
+    pulp_url: "{{ pulp_url }}"
+    username: "{{ pulp_username }}"
+    password: "{{ pulp_password }}"
+    validate_certs: "{{ pulp_validate_certs | bool }}"
+  register: pulp_pubs_list
+
 - name: Ensure RPM distributions are defined
+  vars:
+    repo: "{{ pulp_repos_list.repositories | selectattr('name', 'equalto', item.repository) | first }}"
+    # If the distribution references a specific version:
+    specific_pub: "{{ pulp_pubs_list.publications | selectattr('repository_version', 'equalto', repo.pulp_href ~ 'versions/' ~ item.version | default ~ '/') }}"
+    # If the distribution uses the latest version:
+    latest_pub: "{{ pulp_pubs_list.publications | selectattr('repository', 'equalto', repo.pulp_href) | sort(attribute='repository_version', reverse=True) }}"
+    pub: "{{ latest_pub | first if item.version is not defined else specific_pub | first }}"
   pulp.squeezer.rpm_distribution:
     pulp_url: "{{ pulp_url }}"
     username: "{{ pulp_username }}"
     password: "{{ pulp_password }}"
     validate_certs: "{{ pulp_validate_certs | bool }}"
     name: "{{ item.name }}"
     base_path: "{{ item.base_path }}"
-    publication: "{{ item.publication }}"
+    publication: "{{ pub.pulp_href }}"
     state: "{{ item.state }}"
   with_items: "{{ pulp_distribution_rpm }}"