PLAT-700 Limit ldap heartbeat search query scope and size

lib/ldap.js

@@ -33,7 +33,12 @@ function initializeConnection () {
   });
 
   connection.heartbeat = function (callback) {
-    connection.search('', '(objectclass=*)', function (err, res) {
+    const searchOpts = {
+      filter: '(objectclass=person)',
+      scope: 'sub',
+      sizeLimit: 1
+    };
+    connection.search(nconf.get('LDAP_BASE'), searchOpts , function (err, res) {
       if (err) {
         return callback(err);
       }
@@ -47,7 +52,12 @@ function initializeConnection () {
       res.once('error', function(err) {
         client.removeAllListeners('end');
         clearTimeout(abort);
-        callback(err);
+        // if there are more than one entry matching the search, the server returns the one entry and a SizeLimitExceededError error
+        if (err.name === 'SizeLimitExceededError') {
+          callback();
+        } else {
+          callback(err);
+        }
       }).once('end', function () {
         client.removeAllListeners('error');
         clearTimeout(abort);