Create symlinks for failed builds logs

This allows to know which image failed to build without having to parse
the huge job-output.txt file.

This commit creates a convenient 000_FAILED_image_name.log symlink to
the relevant log files when kolla is configured to output to a log
directory. This creates symlinks only for the parent image with error,
i.e. it skips images that failed to build because of parent error.

Change-Id: I05954e2335dc3fac469276809c91f9c87e3ecab2

kolla/image/build.py

@@ -1018,6 +1018,10 @@ class KollaWorker(object):
                     'name': name,
                     'status': status,
                 })
+                if self.conf.logs_dir and status == STATUS_ERROR:
+                    os.symlink("%s.log" % name,
+                               os.path.join(self.conf.logs_dir,
+                                            "000_FAILED_%s.log" % name))
 
         if self.image_statuses_unmatched:
             LOG.debug("=====================================")

tests/playbooks/post.yml

@@ -65,6 +65,12 @@
               sudo mv $f ${f/.log/.txt}
           done
 
+          # Update symlinks to new file names
+          for f in $(find logs -name "*FAILED*"); do
+              sudo mv ${f} ${f}.gz
+              sudo ln -sf ${f#*/000_FAILED_}.gz ${f}.gz
+          done
+
           # append .txt to all kolla config file
           find logs/kolla_configs -type f -exec mv '{}' '{}'.txt \;