playground_aggregation.json

db.clients.aggregate([
  {
    "$match": {
      "id": "1"
    }
  },
  {
    "$project": {
      "_id": 0,
      "_meta_data": 0
    }
  },
  {
    "$lookup": {
      "from": "queues",
      "as": "queues",
      "localField": "queues",
      "foreignField": "id"
    }
  },
  {
    "$project": {
      "queues": "$queues",
      "listeners": {
        "$reduce": {
          "input": "$queues.listeners",
          "initialValue": [],
          "in": {
            "$concatArrays": [
              "$$value",
              "$$this"
            ]
          }
        }
      }
    }
  },
  {
    "$lookup": {
      "from": "listeners",
      "pipeline": [
        {
          "$project": {
            "_id": 0,
            "_meta_data": 0
          }
        }
      ],
      "as": "resources",
      "localField": "listeners",
      "foreignField": "id"
    }
  },
  {
      $project: {
      "resources": "$resources",
      "resource_paths": {
        "$reduce": {
          "input": "$queues",
          "initialValue": {},
          "in": {
              $mergeObjects: [
              "$$value",
              {
                  $let: {
                    vars: {
                      parent: "$$this.id",
                      children: "$$this.listeners"
                  },
                    in: {
                      $reduce: {
                      "input": "$$children",
                      "initialValue": {},
                        in: {
                          $mergeObjects: [
                          "$$value",
                          {
                              $arrayToObject: [
                              [
                                {
                                    k: "$$this",
                                    v: {
                                      $concat: [
                                      "/",
                                      "queues",
                                      "/",
                                      "$$parent",
                                      "/",
                                      "listeners",
                                      "/",
                                      "$$this"
                                    ]
                                  }
                                }
                              ]
                            ]
                          }
                        ]
                      }
                    }
                  }
                }
              }
            ]
          }
        }
      }
    }
  }
])