Documentation

Using reduce() to construct a JSON.

Send data in JSON body with http.post()

Use the reduce() function to create a JSON object to include as the body with http.post().

  1. Import both the array package to query data and construct table(s), and the http package to transfer JSON over http.

  2. Use array.from() to query data and construct a table. Or, use another method to query data with Flux.

  3. Use the reduce() function to construct a JSON object, and then use yield() to store the output of reduce. This table looks like:

    fieldtag
    example-field:[“3"4"1{example-tag-key:[“bar"bar"bar
  4. Use the map() function to combine the two components together into a JSON object, and then use a second yield() function to store this object as final JSON. This table looks like:

    fieldtagfinal
    example-field:[“3"4"1{example-tag-key:[“bar"bar"bar{example-tag-key:[“bar"bar"bar] , example-field:[“3"4"1]}
  5. Use the findRecord() function to extract the value from the final column, the JSON.

  6. Use http.post() to specify a URL to sent the JSON to. In this example, we use Post Test Server as URL to send the JSON to, and test the http.post() function.

import "array"
import "http"

 
data = array.from(
        rows: [
            {_time: 2020-01-01T00:00:00Z, _field: "example-field", _value: 3, foo: "bar"},
            {_time: 2020-01-01T00:01:00Z, _field: "example-field", _value: 4, foo: "bar"},
            {_time: 2020-01-01T00:02:00Z, _field: "example-field", _value: 1, foo: "bar"},
        ],
    )
  
    |> reduce(
            fn: (r, accumulator) => ({tag:accumulator.tag + "\"" + r.foo, 
                                    field : accumulator.field + "\"" + string(v:r._value)
                                    }),
            identity: {tag: "{example-tag-key:[", 
                    field: "example-field:[" }
    )
    |> yield(name: "output of reduce")
    |> map(fn: (r) => ({ r with tag: r.tag + "]" }))
    |> map(fn: (r) => ({ r with field: r.field + "]}" }))
    |> map(fn: (r) => ({ r with final: r.tag + " , " + r.field}))
    |> yield(name: "final JSON")
    |> findRecord(
        fn: (key) => true,
        idx: 0,
        )


http.post(
    url: "https://ptsv2.com/t/c4x38-1656014222/post",
    headers: {"Content-type": "application/json"},
    data: bytes(v: data.final),
    )

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The future of Flux

Flux is going into maintenance mode. You can continue using it as you currently are without any changes to your code.

Flux is going into maintenance mode and will not be supported in InfluxDB 3.0. This was a decision based on the broad demand for SQL and the continued growth and adoption of InfluxQL. We are continuing to support Flux for users in 1.x and 2.x so you can continue using it with no changes to your code. If you are interested in transitioning to InfluxDB 3.0 and want to future-proof your code, we suggest using InfluxQL.

For information about the future of Flux, see the following: