JSON API Grafana Datasource

The JSON Datasource executes requests against arbitrary backends and parses JSON response into Grafana dataframes.

Contents

• Installation
• Setup
• API
  • /search
  • /query
  • /tag-keys
  • /tag-values
• Development Setup

Installation

To install this plugin using the grafana-cli tool:

 grafana-cli plugins install simpod-json-datasource

See here for more information.

Setup

When adding datasource add your API endpoint to the URL field. That's where datasource will make requests to.

If you want to add custom headers, keep Access set to Server.

API

An OpenAPI definition is defined at openapi.yaml.

To work with this datasource the backend needs to implement 4 endpoints:

• GET / with 200 status code response. Used for "Test connection" on the datasource config page.
• POST /search to return available metrics.
• POST /query to return panel data or annotations.

Those two urls are optional:

• POST /tag-keys returning tag keys for ad hoc filters.
• POST /tag-values returning tag values for ad hoc filters.

/search

POST /search

Grafana issues this request on

1. Variables > New/Edit page. Query field value is passed in a body as shown below (template variables are expanded as regex by default)

{ "target": "query field value" }

Alternatively, flick on the "Raw JSON" switch to provide a full valid JSON string in the query field which will be passed in the request body as a native JSON object.

Template variables will be expanded as a JSON array. For example, selecting two items in a multi-field dropdown $myservers

{"selectedservers":$myservers}

will be expanded to

{"selectedservers":["server1","server2"]}

2. Panel > Queries page. Format As and Metric values are passed in a body as

{ "target": "upper_50" }

The way you handle those values is up to you.

The response body can either contain an array or a map.

Example array response:

["upper_25","upper_50","upper_75","upper_90","upper_95"]

Example map response:

[ { "text": "upper_25", "value": 1}, { "text": "upper_75", "value": 2} ]

/query

POST /query

Example request:

{
  "panelId": 1,
  "range": {
    "from": "2016-10-31T06:33:44.866Z",
    "to": "2016-10-31T12:33:44.866Z",
    "raw": {
      "from": "now-6h",
      "to": "now"
    }
  },
  "rangeRaw": {
    "from": "now-6h",
    "to": "now"
  },
  "interval": "30s",
  "intervalMs": 30000,
  "maxDataPoints": 550,
  "targets": [
     { "target": "Packets", "refId": "A", "payload": { "additional": "optional json" } },
     { "target": "Errors", "refId": "B" }
  ],
  "adhocFilters": [{
    "key": "City",
    "operator": "=",
    "value": "Berlin"
  }]
}

Response body can contain anything that is or can be converted to a Grafana DataFrame using this function. Returned data will be mapped to a DataFrame through that.

Example response (metric value as a float , unix timestamp in milliseconds):

[
  {
    "target":"pps in",
    "datapoints":[
      [622,1450754160000],
      [365,1450754220000]
    ]
  },
  {
    "target":"pps out",
    "datapoints":[
      [861,1450754160000],
      [767,1450754220000]
    ]
  },
  {
    "target":"errors out",
    "datapoints":[
      [861,1450754160000],
      [767,1450754220000]
    ]
  },
  {
    "target":"errors in",
    "datapoints":[
      [861,1450754160000],
      [767,1450754220000]
    ]
  }
]

[
  {
    "columns":[
      {"text":"Time","type":"time"},
      {"text":"Country","type":"string"},
      {"text":"Number","type":"number"}
    ],
    "rows":[
      [1234567,"SE",123],
      [1234567,"DE",231],
      [1234567,"US",321]
    ],
    "type":"table"
  }
]

The relation between target in request and response is 1:n. You can return multiple targets in response for one requested target.

Payload

Sending additional data for each metric is supported via the Payload input field that allows you to enter any JSON string.

For example, when { "additional": "optional json" } is entered into Payload input, it is attached to the target data under "payload" key:

{ "target": "upper_50", "refId": "A", "payload": { "additional": "optional json" } }

You can also enter variables:

/tag-keys

POST /tag-keys

Example request body

{ }

The tag keys api returns:

[
    {"type":"string","text":"City"},
    {"type":"string","text":"Country"}
]

/tag-values

POST /tag-values

Example request body

{"key": "City"}

The tag values api returns:

[
    {"text": "Eins!"},
    {"text": "Zwei"},
    {"text": "Drei!"}
]

Development

Use of Yarn is encouraged to build.

yarn install
yarn run build