From 50e826b0317652390b23aa26ade60095b673173f Mon Sep 17 00:00:00 2001
From: Adam Miller <maxamillion@fedoraproject.org>
Date: Oct 25 2017 16:18:57 +0000
Subject: add module to identify layered image inheritance


Created a module that will take fedora release and a list of layered
images (meant to be provided by the fedcontainer_rc module but can
originate from anywhere) and will provide a dictionary where they
keys are the parent images and the value is a list of children
images. This will assist in automating the layered image rebuild
process.

Signed-off-by: Adam Miller <maxamillion@fedoraproject.org>

---

diff --git a/ansible/fedcontainer_inheritance_demo.yml b/ansible/fedcontainer_inheritance_demo.yml
new file mode 100644
index 0000000..4ed2224
--- /dev/null
+++ b/ansible/fedcontainer_inheritance_demo.yml
@@ -0,0 +1,19 @@
+---
+- name: fedcontainer_inheritance demo
+  hosts: automator
+  vars:
+    fedora_release: 26
+  tasks:
+  - name: Gather list of releases
+    fedcontainer_rc:
+      release: "{{fedora_release}}"
+    register: query_data
+
+  - name: Determine parent image inheritance
+    fedcontainer_inheritance:
+      release: "{{fedora_release}}"
+      layered_images: "{{query_data.rebuildlist}}"
+    register: image_inheritance
+
+  - debug: var=image_inheritance["parent_children"]
+  - debug: var=image_inheritance["errors"]
diff --git a/ansible/library/fedcontainer_inheritance.py b/ansible/library/fedcontainer_inheritance.py
new file mode 100755
index 0000000..0d45cd4
--- /dev/null
+++ b/ansible/library/fedcontainer_inheritance.py
@@ -0,0 +1,134 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# fedcontainer_inheritance.py - Ansible module to gather Fedora container image
+#                               inheritance. This will return a dict.
+#
+# Copyright (C) 2017 Red Hat, Inc.
+# SPDX-License-Identifier:      GPL-2.0+
+#
+# Authors:
+#     Adam Miller <maxamillion@fedoraproject.org>
+#
+
+DOCUMENTATION = '''
+---
+author:
+  - "Adam Miller <maxamillion@fedoraproject.org>"
+module: fedcontainer_inheritance
+short_description: Query Container Parent Image Inheritance
+description:
+  - Query Container Parent Image Inheritance
+  - Returns dict entry 'parent_children' in return JSON, which will contain a
+    dict where the keys are the parent images and the values are the children
+    images.
+options:
+  release:
+    description:
+      - Fedora Release number
+    required: true
+  layered_images:
+    description:
+      - List of layered images that need their inheritance identified
+'''
+
+EXAMPLES = '''
+# Generally meant to be used with other tasks as input, registry the output var
+- fedcontainer_inheritance:
+    release: 26
+  register: image_inheritance
+
+- debug: var=image_inheritance["parent_children"]
+
+
+# More "full featured" example using the fedcontainer_rc module as input
+- name: Gather list of releases
+  fedcontainer_rc:
+    release: 26
+  register: query_data
+
+- name: Determine parent image inheritance
+  fedcontainer_inheritance:
+    release: 26
+    layered_images: "{{query_data.rebuildlist}}"
+  register: image_inheritance
+
+- debug: var=image_inheritance["parent_children"]
+'''
+
+
+##################################################
+# import module snippets
+from ansible.module_utils.basic import *
+
+import re
+
+try:
+    import requests
+except ImportError:
+    module.fail_json("requests python module not found but is required")
+
+def main():
+
+    depchain = {}
+    errors = []
+
+    query_url = "https://src.fedoraproject.org/container/{}/raw/f{}/f/Dockerfile"
+
+    # Define the module and parameters
+    module = AnsibleModule(
+        argument_spec=dict(
+            release=dict(required=True, type="int", default=None),
+            layered_images=dict(required=True, type="list", default=None),
+        ),
+        supports_check_mode=False
+    )
+
+    for container in module.params["layered_images"]:
+
+        # Grab the contents of the Dockerfile
+        r = requests.get(query_url.format(container, module.params["release"]))
+
+        # list comprehension to filter out the FROM line, it's a little overkill
+        # and a little hacky, but it is considerably faster than alternatives.
+        #
+        try:
+            # The logic here is that the list comprehension returns a list
+            # which contains a single element (which we know it will because a
+            # Dockerfile can only have one FROM line), then we look at the
+            # string at index 0 (which is the only thing in the list) and split
+            # it over whitespace and reference the last element, which will be
+            # the parent image of this layered image's Dockerfile.
+            parent_image = [
+                element for element in r.content.split("\n")
+                    if 'FROM' in element
+            ][0].split()[-1]
+
+            # Now we will filter out to make sure that the base images are all
+            # grouped together since they can technically be referenced
+            # short-hand and long form in the FROM line.
+            base_img_key = "fedora:{}".format(module.params["release"])
+            pattern = re.compile(".*{}$".format(base_img_key))
+            if pattern.match(parent_image):
+                parent_base_img_key = [
+                    key for key in depchain.keys()
+                        if pattern.match(key)
+                ]
+                if parent_base_img_key:
+                    parent_image = parent_base_img_key[0]
+
+            depchain.setdefault(parent_image, [])
+            depchain[parent_image].append(container)
+        except IndexError:
+            errors.append(r.content)
+
+
+    module.exit_json(
+        changed=False,
+        msg="Successfully identified container image inheritance, results in 'parent_children'",
+        parent_children=depchain,
+        errors=errors
+    )
+
+main()
+# vim: set expandtab sw=4 sts=4 ts=4