Add detailed help

anticluster.js

@@ -30,6 +30,7 @@ class AntiCluster
             nodeId: this.cfg.node_id,
             heartbeatTimeout: this.cfg.heartbeat_timeout,
             electionTimeout: this.cfg.election_timeout,
+            leaderPriority: this.cfg.leader_priority||undefined,
             initialTerm: this.antietcd.stored_term,
             send: (to, msg) => this._sendRaftMessage(to, msg),
         });

antietcd.js

@@ -196,7 +196,7 @@ class AntiEtcd
             }
             this.clients[client_id].alive = false;
             socket.ping(() => {});
-        }, 30000);
+        }, this.cfg.ws_keepalive_interval||30000);
         socket.on('message', (msg) =>
         {
             try
@@ -434,6 +434,76 @@ function vitastor_persist_filter(prefix)
     };
 }
 
+const help_text = `Miniature etcd replacement based on TinyRaft
+(c) Vitaliy Filippov, 2024
+License: Mozilla Public License 2.0
+
+Usage:
+
+${process.argv[0]} ${process.argv[1]}
+    [--cert ssl.crt] [--key ssl.key] [--port 12379]
+    [--data data.gz] [--vitastor-persist-filter /vitastor] [--no-persist-filter] [--persist_interval 500]
+    [--node_id node1 --cluster_key abcdef --cluster node1=http://localhost:12379,node2=http://localhost:12380,node3=http://localhost:12381]
+    [other options]
+
+Supported etcd REST APIs:
+
+    /v3/kv/txn /v3/kv/put /v3/kv/range /v3/kv/deleterange
+    /v3/lease/grant /v3/lease/keepalive /v3/lease/revoke /v3/kv/lease/revoke
+    websocket-based watch API (create_request, cancel_request, progress_request)
+
+Options:
+
+HTTP:
+
+--port 2379
+    Listen port
+--cert <filename>
+    Use TLS with this certificate file (PEM format)
+--key <filename>
+    Use TLS with this key file (PEM format)
+--ws_keepalive_interval 30000
+    Client websocket ping (keepalive) interval in milliseconds
+
+Persistence:
+
+--data <filename>
+    Use <filename> to store persistent data
+--persist_interval <milliseconds>
+    Persist data on disk after this interval, not immediately
+--no_persist_filter
+    Store all data
+--vitastor_persist_filter <prefix>
+    Store only data required for Vitastor with prefix <prefix> on disk
+
+Clustering:
+
+--node_id <id>
+    ID of this cluster node
+--cluster <id1>=<url1>,<id2>=<url2>,...
+    All other cluster nodes
+--cluster_key <key>
+    Shared cluster key for identification
+--election_timeout 5000
+    Raft election timeout
+--heartbeat_timeout 1000
+    Raft leader heartbeat timeout
+--leader_priority <number>
+    Raft leader priority for this node (optional)
+--stale_read 0|1
+    Allow to serve reads from followers
+--reconnect_interval 1000
+    Unavailable peer connection retry interval
+--dump_timeout 5000
+    Timeout for dump command in milliseconds
+--load_timeout 5000
+    Timeout for load command in milliseconds
+--forward_timeout 1000
+    Timeout for forwarding requests from follower to leader in milliseconds
+--replication_timeout 1000
+    Timeout for replicating requests from leader to follower in milliseconds
+`;
+
 function parse()
 {
     const options = {
@@ -444,13 +514,7 @@ function parse()
         const arg = process.argv[i].toLowerCase().replace(/^--(.+)$/, (m, m1) => '--'+m1.replace(/-/g, '_'));
         if (arg === '-h' || arg === '--help')
         {
-            console.error(
-                'USAGE:\n  '+process.argv[0]+' '+process.argv[1]+' [OPTIONS]\n'+
-                'OPTIONS:\n'+
-                '  [--cert ssl.crt] [--key ssl.key] [--port 12379]\n'+
-                '  [--data data.gz] [--vitastor-persist-filter /vitastor] [--no-persist-filter] [--persist_interval 500]\n'+
-                '  [--node_id node1 --cluster_key abcdef --cluster node1=http://localhost:12379,node2=http://localhost:12380,node3=http://localhost:12381]'
-            );
+            console.error(help_text.trim());
             process.exit();
         }
         else if (arg == '--no_persist_filter')