Documentation

experimental.chain() function

experimental.chain() is subject to change at any time.

experimental.chain() runs two queries in a single Flux script sequentially and outputs the results of the second query.

Flux typically executes multiple queries in a single script in parallel. Running the queries sequentially ensures any dependencies the second query has on the results of the first query are met.

Applicable use cases
  • Write to an InfluxDB bucket and query the written data in a single Flux script.

    _Note: experimental.chain() does not gaurantee that data written to InfluxDB is immediately queryable. A delay between when data is written and when it is queryable may cause a query using experimental.chain() to fail.

  • Execute queries sequentially in testing scenarios.

Function type signature
(first: stream[A], second: stream[B]) => stream[B] where A: Record, B: Record
For more information, see Function type signatures.

Parameters

first

(Required) First query to execute.

second

(Required) Second query to execute.

Examples

Write to a bucket and query the written data

import "experimental"

downsampled_max =
    from(bucket: "example-bucket-1")
        |> range(start: -1d)
        |> filter(fn: (r) => r._measurement == "example-measurement")
        |> aggregateWindow(every: 1h, fn: max)
        |> to(bucket: "downsample-1h-max", org: "example-org")

average_max =
    from(bucket: "downsample-1h-max")
        |> range(start: -1d)
        |> filter(fn: (r) => r.measurement == "example-measurement")
        |> mean()

experimental.chain(first: downsampled_max, second: average_max)

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Linux Package Signing Key Rotation

All signed InfluxData Linux packages have been resigned with an updated key. If using Linux, you may need to update your package configuration to continue to download and verify InfluxData software packages.

For more information, see the Linux Package Signing Key Rotation blog post.