[update] Allow to process single ROS distro, fix 723 (#738)

* [update] skip other distro if --rosdistro passed

Signed-off-by: Mikael Arguedas <mikael.arguedas@gmail.com>

* ignore argument if specified distro doesnt exist

* address review comments

* update help message for rosdistro

Signed-off-by: Mikael Arguedas <mikael.arguedas@gmail.com>

src/rosdep2/main.py

@@ -269,7 +269,7 @@ def setup_environment_variables(ros_distro):
     """
     Set environment variables needed to find ROS packages and evaluate conditional dependencies.
 
-    :param rosdistro: The requested ROS distro passed on the CLI, or None
+    :param ros_distro: The requested ROS distro passed on the CLI, or None
     """
     if ros_distro is not None:
         if 'ROS_DISTRO' in os.environ and os.environ['ROS_DISTRO'] != ros_distro:
@@ -355,7 +355,9 @@ def _rosdep_main(args):
     parser.add_option('--rosdistro', dest='ros_distro', default=None,
                       help='Explicitly sets the ROS distro to use, overriding '
                            'the normal method of detecting the ROS distro '
-                           'using the ROS_DISTRO environment variable.')
+                           'using the ROS_DISTRO environment variable. '
+                           "When used with the 'update' verb, "
+                           'only the specified distro will be updated.')
     parser.add_option('--as-root', default=[], action='append',
                       metavar='INSTALLER_KEY:<bool>', help='Override '
                       'whether sudo is used for a specific installer, '
@@ -643,14 +645,18 @@ def update_error_handler(data_source, exc):
             pass
         update_sources_list(success_handler=update_success_handler,
                             error_handler=update_error_handler,
-                            skip_eol_distros=not options.include_eol_distros)
+                            skip_eol_distros=not options.include_eol_distros,
+                            ros_distro=options.ros_distro)
         print('updated cache in %s' % (sources_cache_dir))
     except InvalidData as e:
         print('ERROR: invalid sources list file:\n\t%s' % (e), file=sys.stderr)
         return 1
     except IOError as e:
         print('ERROR: error loading sources list:\n\t%s' % (e), file=sys.stderr)
         return 1
+    except ValueError as e:
+        print('ERROR: invalid argument value provided:\n\t%s' % (e), file=sys.stderr)
+        return 1
     if error_occured:
         print('ERROR: Not all sources were able to be updated.\n[[[')
         for e in error_occured:

src/rosdep2/sources_list.py

@@ -439,7 +439,7 @@ def _generate_key_from_urls(urls):
 
 def update_sources_list(sources_list_dir=None, sources_cache_dir=None,
                         success_handler=None, error_handler=None,
-                        skip_eol_distros=False):
+                        skip_eol_distros=False, ros_distro=None):
     """
     Re-downloaded data from remote sources and store in cache.  Also
     update the cache index based on current sources.
@@ -487,12 +487,21 @@ def update_sources_list(sources_list_dir=None, sources_cache_dir=None,
     python_versions = {}
 
     print('Query rosdistro index %s' % get_index_url())
-    for dist_name in sorted(get_index().distributions.keys()):
+    distribution_names = get_index().distributions.keys()
+    if ros_distro is not None and ros_distro not in distribution_names:
+        raise ValueError(
+            'Requested distribution "%s" is not in the index.' % ros_distro)
+
+    for dist_name in sorted(distribution_names):
         distribution = get_index().distributions[dist_name]
-        if skip_eol_distros:
-            if distribution.get('distribution_status') == 'end-of-life':
-                print('Skip end-of-life distro "%s"' % dist_name)
+        if dist_name != ros_distro:
+            if ros_distro is not None:
+                print('Skip distro "%s" different from requested "%s"' % (dist_name, ros_distro))
                 continue
+            if skip_eol_distros:
+                if distribution.get('distribution_status') == 'end-of-life':
+                    print('Skip end-of-life distro "%s"' % dist_name)
+                    continue
         print('Add distro "%s"' % dist_name)
         rds = RosDistroSource(dist_name)
         rosdep_data = get_gbprepo_as_rosdep_data(dist_name)