CG metadata for koji task id

Related: https://pagure.io/koji/issue/215

docs/source/content_generator_metadata.rst

@@ -45,6 +45,7 @@ The build map contains the following entries:
 -  owner: The owner of the build task in username format. This field
    is optional.
 -  build_id: Reserved build ID. This field is optional.
+-  task_id: In case there is a corresponding task in koji (int/None)
 -  extra: A map of extra metadata associated with the build, which
    must include at least one of:
 

kojihub/kojihub.py

@@ -6690,6 +6690,11 @@ class CG_Importer(object):
         buildinfo['completion_time'] = \
             datetime.datetime.fromtimestamp(float(metadata['build']['end_time'])).isoformat(' ')
         owner = metadata['build'].get('owner', None)
+        # get task id from OSBS or from standard place
+        if metadata['build'].get('task_id'):
+            buildinfo['task_id'] = int(metadata['build']['task_id'])
+        elif metadata['build'].get('extra', {}).get('container_koji_task_id'):
+            buildinfo['task_id'] = int(metadata['build']['extra']['container_koji_task_id'])
         if owner:
             if not isinstance(owner, str):
                 raise koji.GenericError("Invalid owner format (expected username): %s" % owner)