WIP: API Task Queue

CHANGELOG

@@ -1,3 +1,6 @@
+X.X.X
+* New setting to adjust concurrent rpc calls: rpc_concurrent_tasks, rpc_task_timeout
+
 1.7.4
 * Updated themes to Bootstrap 4.5 by using latest Bootswatch themes
 * Deleted unmaintained themes that were never ported to Bootstrap4

UPGRADE

@@ -1,4 +1,8 @@
 Note: All updates require the explorer to be restarted
+X.X.X
+* Add new setting to settings.json (see settings.json.template)
+  * rpc_concurrent_tasks
+  * rpc_task_timeout
 1.7.3 -> 1.7.4
 * Ensure that you are not using theme "Paper" or "Readable" as these were not ported by Bootswatch
 * Add new settings to settings.json (see settings.json.template)

lib/explorer.js

@@ -7,6 +7,39 @@ var base_url = 'http://127.0.0.1:' + settings.port + '/api/';
 const Client = require('bitcoin-core');
 const client = new Client(settings.wallet);
 
+class API_Task_Queue {
+  constructor() {
+    this.max_tasks = settings.rpc_concurrent_tasks;
+    this.active_tasks = 0;
+  }
+  start_task() {
+    if (this.active_tasks < this.max_tasks) {
+      this.active_tasks++;
+      return true;
+    } else {
+      // console.log('cannot start task');
+      return false;
+    }
+  }
+  finish_task() {
+    this.active_tasks--;
+    return true;
+  }
+  queue_task(run_task) {
+    var Queue = this;
+    if (Queue.start_task()) {
+      return run_task();
+    } else {
+      setTimeout(function() {
+        Queue.finish_task();
+        return Queue.queue_task(run_task);
+      }, settings.rpc_task_timeout);
+    }
+  }
+}
+
+var API_Queue = new API_Task_Queue();
+
 
 // returns coinbase total sent as current coin supply
 function coinbase_supply(cb) {
@@ -20,14 +53,16 @@ function coinbase_supply(cb) {
 }
 
 function rpcCommand(params, cb) {
-  client.command([{method: params[0].method, parameters: params[0].parameters}], function(err, response){
-    if(err){console.log('Error: ', err); }
-    else{
-      if(response[0].name == 'RpcError'){
-        return cb('There was an error. Check your console.');
+  API_Queue.queue_task(function() {
+    client.command([{method: params[0].method, parameters: params[0].parameters}], function(err, response){
+      if(err){console.log('Error: ', err); }
+      else{
+        if(response[0].name == 'RpcError'){
+          return cb('There was an error. Check your console.');
+        }
+        return cb(response[0]);
       }
-      return cb(response[0]);
-    }
+    });
   });
 }
 

lib/settings.js

@@ -126,6 +126,8 @@ exports.confirmations = 6;
 exports.update_timeout = 125;
 exports.check_timeout = 250;
 exports.block_parallel_tasks = 1;
+exports.rpc_concurrent_tasks = 1;
+exports.rpc_task_timeout = 8;
 
 
 //genesis

settings.json.template

@@ -47,6 +47,9 @@
   "update_timeout": 10,
   "check_timeout": 250,
   "block_parallel_tasks": 1,
+  // limits and timeouts for RPC concurrent task queue
+  "rpc_concurrent_tasks": 4,
+  "rpc_task_timeout": 8,
 
   // wallet settings
   "use_rpc": false,