Install the psycopg package if using postgres

ref #4270

roles/pulp3/README.md

@@ -11,6 +11,8 @@ Role Variables:
 * `pulp_cache_dir`: Location of Pulp cache. Defaults to "/var/lib/pulp/tmp".
 * `pulp_config_dir`: Directory which will contain Pulp configuration files.
   Defaults to "/etc/pulp".
+* `pulp_db_type`: Type of db to install packages for. Options are postgres
+  or mysql. Default is postgres.
 * `pulp_default_admin_password`: Initial password for the Pulp admin. **Required**.
 * `pulp_install_dir`: Location of a virtual environment for Pulp and its Python
   dependencies. Defaults to "/usr/local/lib/pulp".

roles/pulp3/defaults/main.yml

@@ -2,6 +2,7 @@
 
 pulp_cache_dir: '/var/lib/pulp/tmp'
 pulp_config_dir: '/etc/pulp'
+pulp_db_type: 'postgres'
 pulp_default_admin_password: ''
 pulp_install_dir: '/usr/local/lib/pulp'
 pulp_install_plugins: {}

roles/pulp3/tasks/install.yml

@@ -66,6 +66,22 @@
         virtualenv: '{{ pulp_install_dir }}'
         virtualenv_command: '{{ pulp_python_interpreter }} -m venv'
 
+    - name: Install the psycopg python package
+      pip:
+        name: psycopg2-binary
+        state: present
+        virtualenv: '{{ pulp_install_dir }}'
+        virtualenv_command: '{{ pulp_python_interpreter }} -m venv'
+      when: pulp_db_type == "postgres"
+
+    - name: Install the mysqlclient python package
+      pip:
+        name: mysqlclient
+        state: present
+        virtualenv: '{{ pulp_install_dir }}'
+        virtualenv_command: '{{ pulp_python_interpreter }} -m venv'
+      when: pulp_db_type == "mysql"
+
     - name: Install pulpcore package from source
       pip:
         name: '{{ pulp_source_dir }}'