checkrepo: provide target_archs() method to determine relevant archs.

The default behavior is to return the archs for which the target project
is built against, but can be used to check any project (like stagings).

osclib/checkrepo.py

@@ -22,6 +22,7 @@ import urllib2
 from xml.etree import cElementTree as ET
 from pprint import pformat
 
+import osc.core
 from osc.core import get_binary_file
 from osc.core import http_DELETE
 from osc.core import http_GET
@@ -592,6 +593,17 @@ class CheckRepo(object):
 
         return repos_to_check
 
+    @memoize(session=True)
+    def target_archs(self, project=None):
+        if not project: project = self.project
+
+        meta = osc.core.show_project_meta(self.apiurl, project)
+        meta = ET.fromstring(''.join(meta))
+        archs = []
+        for arch in meta.findall('repository[@name="standard"]/arch'):
+            archs.append(arch.text)
+        return archs
+
     def is_binary(self, project, repository, arch, package):
         """Return True if is a binary package."""
         root_xml = self.build(project, repository, arch, package)