Primary endpoint (#1439)

python/ccf/clients.py

@@ -341,6 +341,7 @@ class RequestClient:
             "url": f"https://{self.host}:{self.port}{request.path}",
             "auth": auth_value,
             "headers": extra_headers,
+            "allow_redirects": False,
         }
 
         if request.params is not None:
@@ -491,6 +492,9 @@ class CCFClient:
     def delete(self, *args, **kwargs):
         return self.call(*args, http_verb="DELETE", **kwargs)
 
+    def head(self, *args, **kwargs):
+        return self.call(*args, http_verb="HEAD", **kwargs)
+
 
 @contextlib.contextmanager
 def client(

src/node/rpc/endpoint_registry.h

@@ -56,6 +56,7 @@ namespace ccf
   {
     Sometimes,
     Always,
+    Never
   };
 
   /** The EndpointRegistry records the user-defined endpoints for a given

src/node/rpc/frontend.h

@@ -335,6 +335,11 @@ namespace ccf
       {
         switch (endpoint->forwarding_required)
         {
+          case ForwardingRequired::Never:
+          {
+            break;
+          }
+
           case ForwardingRequired::Sometimes:
           {
             if (ctx->session->is_forwarding)

src/node/rpc/node_frontend.h

@@ -317,6 +317,33 @@ namespace ccf
       make_read_only_endpoint(
         "network", HTTP_GET, json_read_only_adapter(network_status))
         .install();
+
+      auto is_primary = [this](ReadOnlyEndpointContext& args) {
+        if (this->node.is_primary())
+        {
+          args.rpc_ctx->set_response_status(HTTP_STATUS_OK);
+        }
+        else
+        {
+          args.rpc_ctx->set_response_status(HTTP_STATUS_PERMANENT_REDIRECT);
+          if (consensus != nullptr)
+          {
+            NodeId primary_id = consensus->primary();
+            auto nodes_view = args.tx.get_read_only_view(this->network.nodes);
+            auto info = nodes_view->get(primary_id);
+            if (info)
+            {
+              args.rpc_ctx->set_response_header(
+                "Location",
+                fmt::format(
+                  "https://{}:{}/node/primary", info->pubhost, info->rpcport));
+            }
+          }
+        }
+      };
+      make_read_only_endpoint("primary", HTTP_HEAD, is_primary)
+        .set_forwarding_required(ForwardingRequired::Never)
+        .install();
     }
   };
 

tests/e2e_logging.py

@@ -539,6 +539,28 @@ def test_tx_statuses(network, args):
     return network
 
 
+@reqs.description("Primary and redirection")
+@reqs.at_least_n_nodes(2)
+def test_primary(network, args, notifications_queue=None, verify=True):
+    LOG.error(network.nodes)
+    primary, _ = network.find_primary()
+    LOG.error(f"PRIMARY {primary.pubhost}")
+    with primary.client() as c:
+        r = c.head("/node/primary")
+        assert r.status == http.HTTPStatus.OK.value
+
+    backup = network.find_any_backup()
+    LOG.error(f"BACKUP {backup.pubhost}")
+    with backup.client() as c:
+        r = c.head("/node/primary")
+        assert r.status == http.HTTPStatus.PERMANENT_REDIRECT.value
+        assert (
+            r.headers["location"]
+            == f"https://{primary.pubhost}:{primary.rpc_port}/node/primary"
+        )
+    return network
+
+
 def run(args):
     hosts = ["localhost"] * (3 if args.consensus == "pbft" else 2)
 
@@ -573,6 +595,7 @@ def run(args):
             network = test_raw_text(network, args)
             network = test_historical_query(network, args)
             network = test_view_history(network, args)
+            network = test_primary(network, args)
             network = test_metrics(network, args)