rest: Add links to /v1 endpoint

This change adds links to /v1 endpoint and
return 200 instead of 400

Change-Id: I41a09a12a53d33cbcdd38c27e6f367ee2b4d5e79
Closes-bug: #1424627

gnocchi/rest/__init__.py

@@ -1174,13 +1174,33 @@ class CapabilityController(rest.RestController):
 
 
 class V1Controller(object):
-    search = SearchController()
-    archive_policy = ArchivePoliciesController()
-    archive_policy_rule = ArchivePolicyRulesController()
-    metric = MetricsController()
-    resource = ResourcesController()
-    aggregation = Aggregation()
-    capabilities = CapabilityController()
+
+    def __init__(self):
+        self.sub_controllers = {
+            "search": SearchController(),
+            "archive_policy": ArchivePoliciesController(),
+            "archive_policy_rule": ArchivePolicyRulesController(),
+            "metric": MetricsController(),
+            "resource": ResourcesController(),
+            "aggregation": Aggregation(),
+            "capabilities": CapabilityController()
+        }
+        for name, ctrl in self.sub_controllers.items():
+            setattr(self, name, ctrl)
+
+    @pecan.expose('json')
+    def index(self):
+        return {
+            "version": "1.0",
+            "links": [
+                {"rel": "self",
+                 "href": pecan.request.application_url + "/v1"}
+            ] + [
+                {"rel": name,
+                 "href": pecan.request.application_url + "/v1/" + name}
+                for name in sorted(self.sub_controllers)
+            ]
+        }
 
 
 class RootController(object):

gnocchi/tests/gabbi/gabbits/resource.yaml

@@ -38,11 +38,13 @@ tests:
           $.versions[0].links[0].href: $SCHEME://$NETLOC/v1/
 
     - name: root of v1
-      desc: https://bugs.launchpad.net/gnocchi/+bug/1424627
       url: /v1
-      xfail: true
-      response_strings:
-          - some hypermedia
+      redirects: true
+      response_json_paths:
+          $.version: "1.0"
+          $.links.`len`: 8
+          $.links[0].href: $SCHEME://$NETLOC/v1
+          $.links[7].href: $SCHEME://$NETLOC/v1/search
 
     - name: root of resource
       url: /v1/resource