Add Zaqar configuration options hook

Currently configuration tables from Zaqar cannot be automatically
generated.

Zaqar registers most of it's options in lazy way, so these options do
not appear in flagmappings file.
Also the options from the embedded zaqar-bench tool end up in
flagmappings file which is wrong.

This patch adds hook for Zaqar which manually registers lazy options and
also unregisters options from embedded zaqar-bench tool. To find all
options hook iterates through all registered entry points under
'oslo.config.opts' group and choses ones which names start from 'zaqar'.

This will make automated generation of configuration tables possible.

Change-Id: I49dc213d0389d8d8dc490d4a63c015a6d861d780

autogenerate_config_docs/hooks.py

@@ -74,8 +74,33 @@ def nova_spice():
     import nova.cmd.spicehtml5proxy  # noqa
 
 
+def zaqar_config():
+    # Zaqar registers most of it's options in lazy way
+    # Let's find all these options and manually register them
+    from oslo_config import cfg
+    import pkg_resources
+
+    zaqar_opts_sets = []
+    for p in pkg_resources.iter_entry_points(group='oslo.config.opts'):
+        if p.name.startswith('zaqar'):
+            zaqar_opts_sets.append(p.load())
+
+    for opts_set in zaqar_opts_sets:
+        for group, options in opts_set():
+            for opt in options:
+                try:
+                    cfg.CONF.register_opt(opt, group=group)
+                except cfg.DuplicateOptError:
+                    pass
+
+    # Let's unregister options that were automatically registered from embedded
+    # zaqar-bench tool during import of Zaqar's modules
+    from zaqar.bench import config as bench_config
+    cfg.CONF.unregister_opts(bench_config._CLI_OPTIONS)
+
 HOOKS = {'aodh': aodh_config,
          'glance.common.config': glance_store_config,
          'keystone.common.config': keystone_config,
          'neutron': neutron_misc,
-         'nova.spice': nova_spice}
+         'nova.spice': nova_spice,
+         'zaqar': zaqar_config}