YAQL use cases

gistfile1.txt

Case 1: Identify hosts with faults detected by Shinken monitoring.  Request made via LiveStatus.
DATA
"result": {
    "result": [
      [
        "bench-05.example.com",
        0
      ],
      [
        "bench-03.example.com",
        0
      ],
      [
        "bench-10.example.com",
        0
      ],
      [
        "bench-07.example.com",
        1
      ]
    ]
}

YAQL
$.result.result.where($[1] > 0).select($[0])

RESULT
[
    "bench-07.example.com"
]

Case 2: Fetch hosts in maintenance mode from Consul
DATA
"result": {
    "result": [
      "280892762",
      [
        {
          "Node": {
            "Node": "bench-03",
            "Datacenter": "dc3",
            "TaggedAddresses": {
              "wan": "x.x.x.x",
              "lan": "x.x.x.x"
            },
            "ModifyIndex": 254298395,
            "Meta": {
              "consul-network-segment": ""
            },
            "Address": "x.x.x.x",
            "CreateIndex": 254253741,
            "ID": "1961be46-28d2-4bde-e47e-02ab67dde013"
          },
          "Checks": [
            {
              "Node": "bench-03",
              "CheckID": "serfHealth",
              "Name": "Serf Health Status",
              "Definition": {},
              "Notes": "",
              "ModifyIndex": 279915946,
              "Status": "passing",
              "ServiceName": "",
              "ServiceID": "",
              "Output": "Agent alive and reachable",
              "ServiceTags": [],
              "CreateIndex": 254253741
            }
          ],
          "Service": {
            "Service": "automation",
            "Tags": [
              "prod",
              "bench"
            ],
            "ModifyIndex": 254253741,
            "EnableTagOverride": false,
            "Port": 0,
            "Meta": null,
            "Address": "bench-03.example.com",
            "CreateIndex": 254253741,
            "ID": "automation"
          }
        },
        {
          "Node": {
            "Node": "bench-05",
            "Datacenter": "dc3",
            "TaggedAddresses": {
              "wan": "x.x.x.x",
              "lan": "x.x.x.x"
            },
            "ModifyIndex": 254375045,
            "Meta": {
              "consul-network-segment": ""
            },
            "Address": "x.x.x.x",
            "CreateIndex": 254253741,
            "ID": "c0b6ae82-d48f-bd5f-ee96-30bf46e2fece"
          },
          "Checks": [
            {
              "Node": "bench-05",
              "CheckID": "serfHealth",
              "Name": "Serf Health Status",
              "Definition": {},
              "Notes": "",
              "ModifyIndex": 278822424,
              "Status": "passing",
              "ServiceName": "",
              "ServiceID": "",
              "Output": "Agent alive and reachable",
              "ServiceTags": [],
              "CreateIndex": 254253741
            }
          ],
          "Service": {
            "Service": "automation",
            "Tags": [
              "prod",
              "bench"
            ],
            "ModifyIndex": 254253741,
            "EnableTagOverride": false,
            "Port": 0,
            "Meta": null,
            "Address": "bench-05.example.com",
            "CreateIndex": 254253741,
            "ID": "automation"
          }
        },
        {
          "Node": {
            "Node": "bench-07",
            "Datacenter": "dc3",
            "TaggedAddresses": {
              "wan": "x.x.x.x",
              "lan": "x.x.x.x"
            },
            "ModifyIndex": 254375625,
            "Meta": {
              "consul-network-segment": ""
            },
            "Address": "x.x.x.x",
            "CreateIndex": 254253741,
            "ID": "dcec1af3-d7a8-5aa8-3cf4-4cbc037fc077"
          },
          "Checks": [
            {
              "Node": "bench-07",
              "CheckID": "serfHealth",
              "Name": "Serf Health Status",
              "Definition": {},
              "Notes": "",
              "ModifyIndex": 254253741,
              "Status": "passing",
              "ServiceName": "",
              "ServiceID": "",
              "Output": "Agent alive and reachable",
              "ServiceTags": [],
              "CreateIndex": 254253741
            }
          ],
          "Service": {
            "Service": "automation",
            "Tags": [
              "prod",
              "bench"
            ],
            "ModifyIndex": 254253741,
            "EnableTagOverride": false,
            "Port": 0,
            "Meta": null,
            "Address": "bench-07.example.com",
            "CreateIndex": 254253741,
            "ID": "automation"
          }
        },
        {
          "Node": {
            "Node": "bench-10",
            "Datacenter": "dc3",
            "TaggedAddresses": {
              "wan": "x.x.x.x",
              "lan": "x.x.x.x"
            },
            "ModifyIndex": 254375694,
            "Meta": {
              "consul-network-segment": ""
            },
            "Address": "x.x.x.x",
            "CreateIndex": 254253741,
            "ID": "18dfa090-9ccc-01ac-1c34-afa456ee39a4"
          },
          "Checks": [
            {
              "Node": "bench-10",
              "CheckID": "serfHealth",
              "Name": "Serf Health Status",
              "Definition": {},
              "Notes": "",
              "ModifyIndex": 254375693,
              "Status": "passing",
              "ServiceName": "",
              "ServiceID": "",
              "Output": "Agent alive and reachable",
              "ServiceTags": [],
              "CreateIndex": 254253741
            }
          ],
          "Service": {
            "Service": "automation",
            "Tags": [
              "prod",
              "bench"
            ],
            "ModifyIndex": 254253741,
            "EnableTagOverride": false,
            "Port": 0,
            "Meta": null,
            "Address": "bench-10.example.com",
            "CreateIndex": 254253741,
            "ID": "automation"
          }
        }
      ]
    ]
}

YAQL
$.result.result.last().select([$.Checks.where($.CheckID = "_service_maintenance:automation" or $.CheckID = "_node_maintenance").select($.Status), $.Service.Address]).where(len($[0]) > 0).select($[1])

RESULT:
[]

Case 3: Merge three lists to produce a single list of unique hosts.
DATA
{}
VAR
farm_problem_list = ["bench-07.example.com"],
host_in_maintenance = [],
hosts_failed = ["bench-03.example.com, "bench-07.example.com"]

YAQL
($.hosts_failed + $.farm_problem_list + $.hosts_in_maintenance).distinct()

RESULT
["bench-07.example.com", "bench-03.example.com"]