Add OSTree dependencies to pulp_installer

[pulpbot]

Author: @lubosmj (lmjachky)

Redmine Issue: 9212, https://pulp.plan.io/issues/9212

---

The pulp_ostree plugin needs some prerequisites, similarly to pulp_rpm https://github.com/pulp/pulp_installer/tree/master/roles/pulp_rpm_prerequisites.

The required packages to install are:

1. ostree (a client application that enables management of OSTree repositories)
2. ostree-libs (a library that enables pulp_ostree to run OSTree commands via python bindings)

[lubosmj]

For an unpinned PyGObject requirement:

[lmjachky@localhost pulp_ostree]$ cat requirements.txt
pulpcore>=3.15.0
PyGObject

I was able to spin up a new VM with the following changes:

diff --git a/example.dev-config.yml b/example.dev-config.yml
index 2963fab..d448ee9 100644
--- a/example.dev-config.yml
+++ b/example.dev-config.yml
@@ -13,8 +13,10 @@ pulp_install_plugins:
   #   # git_revision: "0.7.3"  # optional specific branch/tag/commit
   # pulp-certguard:
   #   source_dir: "/home/vagrant/devel/pulp-certguard"
   # pulp-container:
   #   source_dir: "/home/vagrant/devel/pulp_container"
+  pulp-ostree:
+    source_dir: "/home/vagrant/devel/pulp_ostree"
   # pulp-cookbook:
   #   source_dir: "/home/vagrant/devel/pulp_cookbook"
   # pulp-deb:
diff --git a/roles/pulp_common/tasks/install_pip.yml b/roles/pulp_common/tasks/install_pip.yml
index 5a72e79..18c45f5 100644
--- a/roles/pulp_common/tasks/install_pip.yml
+++ b/roles/pulp_common/tasks/install_pip.yml
@@ -329,6 +329,20 @@
       tags:
         - molecule-idempotence-notest
 
+    - name: Install Pycairo
+      pip:
+        name: pycairo
+        state: present
+        virtualenv: '{{ pulp_install_dir }}'
+        virtualenv_command: '{{ pulp_python_interpreter }} -m venv'
+
+    - name: Install PyGObject
+      pip:
+        name: PyGObject
+        state: present
+        virtualenv: '{{ pulp_install_dir }}'
+        virtualenv_command: '{{ pulp_python_interpreter }} -m venv'
+
     - name: Install Pulp plugins from source
       pip:
         name: '{{ item.value.source_dir }}'
@@ -362,6 +376,7 @@
         virtualenv: '{{ pulp_install_dir }}'
         virtualenv_command: '{{ pulp_python_interpreter }} -m venv'
 
   become: true
   become_user: '{{ pulp_user }}'
 ...
diff --git a/roles/pulp_common/vars/Fedora.yml b/roles/pulp_common/vars/Fedora.yml
index 3581ff8..36d17f6 100644
--- a/roles/pulp_common/vars/Fedora.yml
+++ b/roles/pulp_common/vars/Fedora.yml
@@ -10,6 +10,12 @@ pulp_preq_packages:
   - git                 # For source install, and SELinux policy install
   - sudo
   - gnupg2              # For the signing service via the gpg python module
+  - gobject-introspection-devel
+  - cairo-gobject-devel
+  - pkg-config
+  - python3-devel
+  - gtk3
+  - ostree
 
 # Pulp requires Python 3.8+.
 pulp_python_interpreter: /usr/bin/python3

Not sure what is really needed and what are the least viable installation requirements. Problems may arise during the installation of PyGObject (therefore, it is necessary to add more dependencies to other distros, like in https://pygobject.readthedocs.io/en/latest/getting_started.html#fedora-logo-fedora).