Check the current number of connections to MongoDb

Question

What is the command to get the number of clients connected to a particular MongoDB server?

Answer 1

Sorry because this is an old post and currently there is more options than before.

db.getSiblingDB("admin").aggregate( [
   { $currentOp: { allUsers: true, idleConnections: true, idleSessions: true } }
  ,{$project:{
            "_id":0
           ,client:{$arrayElemAt:[ {$split:["$client",":"]}, 0 ] }
           ,curr_active:{$cond:[{$eq:["$active",true]},1,0]}
           ,curr_inactive:{$cond:[{$eq:["$active",false]},1,0]}
           }
   }
  ,{$match:{client:{$ne: null}}}
  ,{$group:{_id:"$client",curr_active:{$sum:"$curr_active"},curr_inactive:{$sum:"$curr_inactive"},total:{$sum:1}}}
  ,{$sort:{total:-1}}
] )

Output example:

{ "_id" : "xxx.xxx.xxx.78", "curr_active" : 0, "curr_inactive" : 1428, "total" : 1428 }
{ "_id" : "xxx.xxx.xxx.76", "curr_active" : 0, "curr_inactive" : 1428, "total" : 1428 }
{ "_id" : "xxx.xxx.xxx.73", "curr_active" : 0, "curr_inactive" : 1428, "total" : 1428 }
{ "_id" : "xxx.xxx.xxx.77", "curr_active" : 0, "curr_inactive" : 1428, "total" : 1428 }
{ "_id" : "xxx.xxx.xxx.74", "curr_active" : 0, "curr_inactive" : 1428, "total" : 1428 }
{ "_id" : "xxx.xxx.xxx.75", "curr_active" : 0, "curr_inactive" : 1428, "total" : 1428 }
{ "_id" : "xxx.xxx.xxx.58", "curr_active" : 0, "curr_inactive" : 510, "total" : 510 }
{ "_id" : "xxx.xxx.xxx.57", "curr_active" : 0, "curr_inactive" : 459, "total" : 459 }
{ "_id" : "xxx.xxx.xxx.55", "curr_active" : 0, "curr_inactive" : 459, "total" : 459 }
{ "_id" : "xxx.xxx.xxx.56", "curr_active" : 0, "curr_inactive" : 408, "total" : 408 }
{ "_id" : "xxx.xxx.xxx.47", "curr_active" : 1, "curr_inactive" : 11, "total" : 12 }
{ "_id" : "xxx.xxx.xxx.48", "curr_active" : 1, "curr_inactive" : 7, "total" : 8 }
{ "_id" : "xxx.xxx.xxx.51", "curr_active" : 0, "curr_inactive" : 8, "total" : 8 }
{ "_id" : "xxx.xxx.xxx.46", "curr_active" : 0, "curr_inactive" : 8, "total" : 8 }
{ "_id" : "xxx.xxx.xxx.52", "curr_active" : 0, "curr_inactive" : 6, "total" : 6 }
{ "_id" : "127.0.0.1", "curr_active" : 1, "curr_inactive" : 0, "total" : 1 }
{ "_id" : "xxx.xxx.xxx.3", "curr_active" : 0, "curr_inactive" : 1, "total" : 1 }