main.json

{
  "metric_keys": [
    "puma_threads"
  ],
  "dashboard": {
    "title": "Puma metrics",
    "description": "Track Puma workers on this dashboard,\nsee how many worker processes are running\nand what the used/available concurrency is for those workers.\n",
    "visuals": [
      {
        "type": "timeseries",
        "display": "line",
        "format": "number",
        "draw_null_as_zero": true,
        "title": "Threads running/max",
        "description": "Number of threads (over all workers, if running multiple processes)",
        "line_label": "%type% - %hostname%",
        "metrics": [
          {
            "name": "puma_threads",
            "fields": [
              {
                "field": "gauge"
              }
            ],
            "tags": [
              {
                "key": "hostname",
                "value": "*"
              },
              {
                "key": "type",
                "value": "*"
              }
            ]
          }
        ]
      },
      {
        "type": "timeseries",
        "display": "line",
        "format": "number",
        "draw_null_as_zero": true,
        "title": "Connection backlog",
        "description": "Connections waiting to be processed in the server backlog queue.",
        "line_label": "%hostname%",
        "metrics": [
          {
            "name": "puma_connection_backlog",
            "fields": [
              {
                "field": "gauge"
              }
            ],
            "tags": [
              {
                "key": "hostname",
                "value": "*"
              }
            ]
          }
        ]
      },
      {
        "type": "timeseries",
        "display": "line",
        "format": "number",
        "draw_null_as_zero": true,
        "title": "Pool capacity",
        "description": "How many idle threads are ready to receive requests.",
        "line_label": "%hostname%",
        "metrics": [
          {
            "name": "puma_pool_capacity",
            "fields": [
              {
                "field": "gauge"
              }
            ],
            "tags": [
              {
                "key": "hostname",
                "value": "*"
              }
            ]
          }
        ]
      },
      {
        "type": "timeseries",
        "display": "line",
        "format": "number",
        "draw_null_as_zero": true,
        "title": "Workers",
        "description": "After a deploy, old workers should be replaced with newly booted workers.",
        "line_label": "%type% - %hostname%",
        "metrics": [
          {
            "name": "puma_workers",
            "fields": [
              {
                "field": "gauge"
              }
            ],
            "tags": [
              {
                "key": "hostname",
                "value": "*"
              },
              {
                "key": "type",
                "value": "*"
              }
            ]
          }
        ]
      }
    ]
  }
}