Fix 'limit' and 'marker' error in provider listing

Currently, providers API's parameters like 'limit' and
'marker' are not really used, but python-karborclient
use them. This patch will add the processing of 'limit'
and 'marker' in providers API.

Change-Id: I6a6206948adc1c417177a1b9c0f54aa2c0b8ef7e
Closes-Bug: #1717827

karbor/services/protection/provider.py

@@ -197,11 +197,23 @@ class ProviderRegistry(object):
 
     def list_providers(self, marker=None, limit=None, sort_keys=None,
                        sort_dirs=None, filters=None):
-        # TODO(wangliuan) How to use the list option
-        return [dict(id=provider.id, name=provider.name,
+        # TODO(jiaopengju) How to use sort_keys, sort_dirs and filters
+        provider_ids = sorted(self.providers.keys())
+        provider_list = sorted(
+            self.providers.values(), key=lambda item: item.id)
+        if marker is not None and marker in provider_ids:
+            provider_list = provider_list[provider_ids.index(marker) + 1:]
+        valid_providers = []
+        for provider in provider_list:
+            valid_providers.append(
+                dict(id=provider.id,
+                     name=provider.name,
                      description=provider.description,
-                     extended_info_schema=provider.extended_info_schema)
-                for provider in self.providers.values()]
+                     extended_info_schema=provider.extended_info_schema
+                     ))
+            if limit is not None and len(valid_providers) == limit:
+                return valid_providers
+        return valid_providers
 
     def show_provider(self, provider_id):
         try:

karbor/tests/unit/protection/test_provider.py

@@ -36,6 +36,31 @@ resource_graph = {
 }
 
 
+def set_provider_list(provider_registry):
+    provider_registry.providers = {
+        'fake_provider_id_1': FakeProvider(
+            id='fake_provider_id_1',
+            name='fake_provider_name_1',
+            description='',
+            extended_info_schema=''
+        ),
+        'fake_provider_id_2': FakeProvider(
+            id='fake_provider_id_2',
+            name='fake_provider_name_2',
+            description='',
+            extended_info_schema=''
+        )
+    }
+
+
+class FakeProvider(object):
+    def __init__(self, id, name, description, extended_info_schema):
+        self.id = id
+        self.name = name
+        self.description = description
+        self.extended_info_schema = extended_info_schema
+
+
 class ProviderRegistryTest(base.TestCase):
     def setUp(self):
         super(ProviderRegistryTest, self).setUp()
@@ -67,6 +92,18 @@ class ProviderRegistryTest(base.TestCase):
         pr = provider.ProviderRegistry()
         self.assertEqual(1, len(pr.list_providers()))
 
+    def test_list_provider_with_marker(self):
+        pr = provider.ProviderRegistry()
+        set_provider_list(pr)
+        self.assertEqual(
+            1, len(pr.list_providers(marker='fake_provider_id_1')))
+
+    def test_list_provider_with_limit(self):
+        pr = provider.ProviderRegistry()
+        set_provider_list(pr)
+        self.assertEqual(
+            1, len(pr.list_providers(limit=1)))
+
     def test_show_provider(self):
         pr = provider.ProviderRegistry()
         provider_list = pr.list_providers()