From f3cb6cbd5d3872a36ad4a510320575fbb1796094 Mon Sep 17 00:00:00 2001
From: Yashvardhan Nanavati <yashn@bu.edu>
Date: Mar 18 2019 16:17:03 +0000
Subject: Return warning if there is no parent policy for a remote rule policy


Users mistakenly configure a parent policy with a decision_context and
 a gating.yaml file with another decision_context. This can cause unnecessary
delays for the user. In order to avoid this, add a check in the validate_gating_yaml
endpoint to print a warning message notifying the user about it.

---

diff --git a/functional-tests/test_api_v1.py b/functional-tests/test_api_v1.py
index f325e2e..b625494 100644
--- a/functional-tests/test_api_v1.py
+++ b/functional-tests/test_api_v1.py
@@ -958,7 +958,7 @@ def test_validate_gating_yaml_valid(requests_session, greenwave_server):
         id: "test"
         product_versions:
           - fedora-26
-        decision_context: test
+        decision_context: container-image-test
         rules:
           - !PassingTestCaseRule {test_case_name: test}
     """)
@@ -1031,6 +1031,34 @@ def test_validate_gating_yaml_missing_tag(requests_session, greenwave_server):
     assert result.status_code == 400
 
 
+def test_validate_gating_yaml_missing_decision_context(requests_session, greenwave_server):
+    gating_yaml = dedent("""
+        --- !Policy
+        id: "test"
+        product_versions:
+          - fedora-26
+        decision_context: test_missing_1
+        rules:
+          - !PassingTestCaseRule {test_case_name: test}
+
+        --- !Policy
+        id: "test_2"
+        product_versions:
+          - fedora-26
+        decision_context: test_missing_2
+        rules:
+          - !PassingTestCaseRule {test_case_name: test_2}
+    """)
+    result = requests_session.post(
+        greenwave_server + 'api/v1.0/validate-gating-yaml', data=gating_yaml)
+    assert result.json().get('message') == ('Greenwave could not find a parent policy(ies) for '
+                                            'following decision context(s): '
+                                            'test_missing_1, test_missing_2. Please change your'
+                                            ' policy so that it will match a decision'
+                                            ' context in the parent policies.')
+    assert result.status_code == 200
+
+
 def test_make_a_decision_about_compose_all_variants_architectures(
         requests_session, greenwave_server, testdatabuilder):
     compose_id = testdatabuilder.unique_compose_id()
diff --git a/greenwave/api_v1.py b/greenwave/api_v1.py
index 9a83588..7c472e5 100644
--- a/greenwave/api_v1.py
+++ b/greenwave/api_v1.py
@@ -5,7 +5,9 @@ from flask import Blueprint, request, current_app, jsonify, url_for, redirect, R
 from werkzeug.exceptions import BadRequest, NotFound, UnsupportedMediaType
 from prometheus_client import generate_latest
 from greenwave import __version__
-from greenwave.policies import summarize_answers, RemotePolicy
+from greenwave.policies import (summarize_answers,
+                                RemotePolicy,
+                                _missing_decision_contexts_in_parent_policies)
 from greenwave.resources import ResultsRetriever, retrieve_waivers
 from greenwave.safe_yaml import SafeYAMLError
 from greenwave.utils import insert_headers, jsonp
@@ -437,11 +439,18 @@ def validate_gating_yaml_post():
         log.error('No policies defined')
         raise BadRequest('No policies defined')
 
+    missing_decision_contexts = _missing_decision_contexts_in_parent_policies(policies)
     if any(True for policy in policies if policy.blacklist):
         msg = {'message': ('The gating.yaml file is valid but it is using the deprecated '
                            '"blacklist" key. Please use "excluded_packages" instead.')}
+    elif missing_decision_contexts:
+        msg = {'message': ('Greenwave could not find a parent policy(ies) for following decision'
+                           ' context(s): {}. Please change your policy so that it will match a '
+                           'decision context in the parent policies.'.format(
+                               ', '.join(missing_decision_contexts)))}
     else:
         msg = {'message': 'All OK'}
+
     return jsonify(msg)
 
 
diff --git a/greenwave/policies.py b/greenwave/policies.py
index b04e3b5..b3b6f4a 100644
--- a/greenwave/policies.py
+++ b/greenwave/policies.py
@@ -7,6 +7,7 @@ import logging
 import os
 import re
 import greenwave.resources
+from flask import current_app
 
 from greenwave.safe_yaml import (
     SafeYAMLChoice,
@@ -638,3 +639,19 @@ def applicable_decision_context_product_version_pairs(policies, **attributes):
 
     log.debug("found %i decision contexts", len(contexts_product_versions))
     return contexts_product_versions
+
+
+def _missing_decision_contexts_in_parent_policies(policies):
+    missing_decision_contexts = []
+    for policy in policies:
+        # Assume a parent policy is not present for a policy in the remote rule
+        parent_present = False
+        for parent_policy in current_app.config['policies']:
+            if parent_policy.decision_context == policy.decision_context:
+                parent_present = True
+                break
+        # If there are no parent policies for a decision_context in the remote rule,
+        # report it as missing to warn the user.
+        if not parent_present:
+            missing_decision_contexts.append(policy.decision_context)
+    return missing_decision_contexts