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json_exporter

A prometheus exporter which scrapes JSON objects to collect metrics. Inspired by json_exporter but using jq expression instead of JSONPath and webhook for the source.

Example Usage

1. configure and run json_exporter with test config

export TEST_SHARED_WEB_HOOK_KEY="some-secret"
export EXPORTER_CONFIG=test/config.yaml
go build && ./json_exporter

2. send json payload to exporter's webhooks

# send data to example webhook with secret
> curl -i -d @test/data.json \
    -H "Authorization:some-secret" \
    http://localhost:9000/webhook/example

HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Date: Mon, 01 Jan 2024 22:37:06 GMT
Content-Length: 2
Content-Type: text/plain; charset=utf-8

ok

# send data to animals webhook
> curl -i -d @test/animal-data.json \
    http://localhost:9000/animals

HTTP/1.1 204 No Content
Date: Mon, 01 Jan 2024 22:37:06 GMT

3. verify metrics on exporter

❯ curl http://localhost:9000/metrics

# HELP animal_population Example of top-level lists in a separate collectors
# TYPE animal_population gauge
animal_population{name="deer",predator="false"} 456
animal_population{name="lion",predator="true"} 123
animal_population{name="pigeon",predator="false"} 789
# HELP example_global_value Example of a top-level global value scrape in the json
# TYPE example_global_value gauge
example_global_value{environment="beta",location="planet-mars"} 1234
# HELP example_inactive_value_count Example of a timestamped value scrape in the json
# TYPE example_inactive_value_count counter
example_inactive_value_count{environment="beta"} 2
# HELP example_value_active Example of sub-level value scrapes from a json
# TYPE example_value_active counter
example_value_active{environment="beta",id="id-A"} 1
example_value_active{environment="beta",id="id-C"} 1
# HELP example_value_boolean Example of sub-level value scrapes from a json
# TYPE example_value_boolean counter
example_value_boolean{environment="beta",id="id-A"} 1
example_value_boolean{environment="beta",id="id-C"} 0
# HELP example_value_count Example of sub-level value scrapes from a json
# TYPE example_value_count counter
example_value_count{environment="beta",id="id-A"} 1
example_value_count{environment="beta",id="id-C"} 3

Collector Config

collectors:
  # id of the collector
  example: 
    # namespace for all metrics of the collector
    namespace: example
    # labels shared with all metrics of the collector 
    defaultLabels: 
        # name of the label
      - name: environment
        # value (jq expression): evaluated on json object of metric
        # its always relative to metric's 'path' exp
        value: '"beta"'
    # list of all the metrics of the collector
    metrics:
      - name: global_value
        help: Example of a top-level global value scrape in the json
        # type of the metrics value should be either 'counter' or 'gauge'
        # default is counter
        type: gauge
        # path (jq expression): path exp for the json object on which this metrics should be collected
        # default is '.'
        path: "."
        # filter (jq expression): metric collection will be skipped if this
        # exp results in 'false' value
        filter: "."
        # value (jq expression): should result in the value of the metric
        # default is 1
        value: .counter
        # 'operation' is only used for gauge metrics
        # value should be either 'set' or 'add', default is 'set'
        # 'set' sets the Gauge to an given value.
        # 'add' adds the given value to the Gauge. (The value can be negative,
        # resulting in a decrease of the Gauge.)
        operation: set
        # labels specific to this metric
        labels:
          - name: location
            value: '"planet-"+ .location'

      - name: inactive_value_count
        help: Example of a timestamped value scrape in the json
        path: .values[]
        filter: '.state == "INACTIVE"'
        value: ".count"

  animals:
    defaultLabels:
      - name: name
        value: .noun
    metrics:
      - name: animal_population
        help: Example of top-level lists in a separate collectors
        type: gauge
        path: ".[]"
        value: .population
        labels:
          - name: predator
            value: .predator

Notes:

  • at the moment only counter and gauge metrics are supported. if metric type is counter given value will be added to the metrics, for gauge value will be set.

  • to set const value use value: '"beta"' for this exp value will always be beta

  • jq doesn't support the "decimal fraction" in timestamp. to truncate use | .[0:19] +"Z" | fromdateiso8601..

    jq -nr '"2020-12-11T01:00:52.605001Z" | .[0:19] +"Z" | fromdateiso8601'

Webhook Config

webhooks:
  # id of the webhook
  example:
    # allowed method for the HTTP request.
    method: POST
    # The URL path on which requests are sent.
    path: /webhook/example
    auth:
      # A list of HTTP headers and values all request must have
      headers:
        - name: Authorization
          valueFromEnv: TEST_SHARED_WEB_HOOK_KEY
        - name: Content-Type
          value: application/json
    # Specifies the HTTP response that will be returned on successful requests.
    response:
      code: 200
      headers:
        - name: Access-Control-Allow-Origin
          value: "*"
      message: "ok"
    # list of collectors where received payload will be sent
    collectors:
        # id of the collector
      - id: example
        # transform is a jq expression which will be executed on payload and 
        # output will be sent to collector
        transform: "."

  animals:
    method: POST
    path: /animals
    response:
      code: 204
    collectors:
      - id: animals

Note:

  • webhooks will use same port as metrics server