Add zuul.child_jobs in ansible inventory file

A job may want to know information about the first level of child jobs
that will run after it, to provide this information we now include
zuul.child_jobs (as list) in the inventory file.

Change-Id: I17386d4aa1409b7ac996518981501c2d22899434
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

doc/source/user/jobs.rst

@@ -175,6 +175,11 @@ of item.
       configuration of items ahead in a dependent pipeline changes,
       Zuul creates a new buildset and restarts all of the jobs.
 
+   .. var:: child_jobs
+
+      A list of the first level child jobs to be run after this job
+      has finished successfully.
+
    .. var:: ref
 
       The git ref of the item.  This will be the full path (e.g.,

releasenotes/notes/inventory-zuul-child-jobs-0e7cf28f0cab83b8.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    A new Ansible inventory variable :var:`zuul.child_jobs` which is a
+    list of the first level child jobs to be run after a job has
+    finished successfully.

tests/fixtures/config/ansible/git/common-config/playbooks/check-vars.yaml

@@ -8,6 +8,13 @@
           - nodepool.region == 'test-region'
           - nodepool.provider == 'test-provider'
 
+    - name: Assert zuul variables are valid.
+      assert:
+        that:
+          - zuul.child_jobs is defined
+          - zuul.child_jobs|length == 1
+          - "'check-hostvars' in zuul.child_jobs"
+
     - name: Assert zuul-executor variables are valid.
       assert:
         that:
@@ -39,4 +46,4 @@
           - vartest_job == 'vartest_job'
           - vartest_secret.value == 'vartest_secret'
           - vartest_site == 'vartest_site'
-          - base_var == 'base_var'
+          - base_var == 'base_var'

tests/fixtures/config/ansible/git/org_project/.zuul.yaml

@@ -15,8 +15,12 @@
         - python27
         - faillocal
         - check-vars
-        - check-hostvars
-        - check-secret-names
+        - check-hostvars:
+            dependencies:
+              - check-vars
+        - check-secret-names:
+            dependencies:
+              - check-hostvars
         - timeout
         - post-timeout
         - hello-world

zuul/executor/client.py

@@ -182,6 +182,8 @@ class ExecutorClient(object):
             zuul_params['newrev'] = item.change.newrev
         zuul_params['projects'] = {}  # Set below
         zuul_params['items'] = dependent_changes
+        zuul_params['child_jobs'] = list(item.job_graph.getDirectDependentJobs(
+            job.name))
 
         params = dict()
         params['job'] = job.name

zuul/model.py

@@ -1394,7 +1394,7 @@ class JobGraph(object):
     def getJobs(self):
         return list(self.jobs.values())  # Report in the order of layout cfg
 
-    def _getDirectDependentJobs(self, parent_job):
+    def getDirectDependentJobs(self, parent_job):
         ret = set()
         for dependent_name, parent_names in self._dependencies.items():
             if parent_job in parent_names:
@@ -1406,7 +1406,7 @@ class JobGraph(object):
         jobs_to_iterate = set([parent_job])
         while len(jobs_to_iterate) > 0:
             current_job = jobs_to_iterate.pop()
-            current_dependent_jobs = self._getDirectDependentJobs(current_job)
+            current_dependent_jobs = self.getDirectDependentJobs(current_job)
             new_dependent_jobs = current_dependent_jobs - all_dependent_jobs
             jobs_to_iterate |= new_dependent_jobs
             all_dependent_jobs |= new_dependent_jobs