Network: Support simple liveness check via http on gossip server port.

node/follower_node.go

@@ -127,6 +127,11 @@
 	}
 
 	node.ledger.RegisterBlockListeners(blockListeners)
+
+	if cfg.IsGossipServer() {
+		rpcs.MakeHealthService(node.net)
+	}
+
 	node.blockService = rpcs.MakeBlockService(node.log, cfg, node.ledger, p2pNode, node.genesisID)
 	node.catchupBlockAuth = blockAuthenticatorImpl{Ledger: node.ledger, AsyncVoteVerifier: agreement.MakeAsyncVoteVerifier(node.lowPriorityCryptoVerificationPool)}
 	node.catchupService = catchup.MakeService(node.log, node.config, p2pNode, node.ledger, node.catchupBlockAuth, make(chan catchup.PendingUnmatchedCertificate), node.lowPriorityCryptoVerificationPool)

node/node.go

@@ -251,6 +251,11 @@
 		return nil, err
 	}
 
+	// The health service registers itself with the network
+	if cfg.IsGossipServer() {
+		rpcs.MakeHealthService(node.net)
+	}
+
 	node.blockService = rpcs.MakeBlockService(node.log, cfg, node.ledger, p2pNode, node.genesisID)
 	node.ledgerService = rpcs.MakeLedgerService(cfg, node.ledger, p2pNode, node.genesisID)
 	rpcs.RegisterTxService(node.transactionPool, p2pNode, node.genesisID, cfg.TxPoolSize, cfg.TxSyncServeResponseSize)

rpcs/healthService.go

@@ -0,0 +1,41 @@
+// Copyright (C) 2019-2024 Algorand, Inc.
+// This file is part of go-algorand
+//
+// go-algorand is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// go-algorand is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with go-algorand.  If not, see <https://www.gnu.org/licenses/>.
+
+package rpcs
+
+import (
+	"github.com/algorand/go-algorand/network"
+	"net/http"
+)
+
+// HealthServiceStatusPath is the path to register HealthService as a handler for when using gorilla/mux
+const HealthServiceStatusPath = "/status"
+
+// HealthService is a service that provides health information endpoints for the node
+type HealthService struct{}
+
+// MakeHealthService creates a new HealthService and registers it with the provided network if enabled
+func MakeHealthService(net network.GossipNode) HealthService {
+	service := HealthService{}
+
+	net.RegisterHTTPHandler(HealthServiceStatusPath, service)
+
+	return service
+}
+
+func (h HealthService) ServeHTTP(writer http.ResponseWriter, _ *http.Request) {
+	writer.WriteHeader(http.StatusOK)
+}

rpcs/healthService_test.go

@@ -0,0 +1,52 @@
+// Copyright (C) 2019-2024 Algorand, Inc.
+// This file is part of go-algorand
+//
+// go-algorand is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// go-algorand is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with go-algorand.  If not, see <https://www.gnu.org/licenses/>.
+
+package rpcs
+
+import (
+	"github.com/algorand/go-algorand/network"
+	"github.com/algorand/go-algorand/test/partitiontest"
+	"github.com/stretchr/testify/require"
+	"io"
+	"net/http"
+	"path"
+	"testing"
+)
+
+func TestHealthService_ServeHTTP(t *testing.T) {
+	partitiontest.PartitionTest(t)
+
+	nodeA := &basicRPCNode{}
+	nodeA.start()
+	defer nodeA.stop()
+
+	_ = MakeHealthService(nodeA)
+
+	parsedURL, err := network.ParseHostOrURL(nodeA.rootURL())
+	require.NoError(t, err)
+
+	client := http.Client{}
+
+	parsedURL.Path = path.Join(parsedURL.Path, HealthServiceStatusPath)
+
+	response, err := client.Get(parsedURL.String())
+	require.NoError(t, err)
+
+	require.Equal(t, http.StatusOK, response.StatusCode)
+	bodyData, err := io.ReadAll(response.Body)
+	require.NoError(t, err)
+	require.Empty(t, bodyData)
+}