Documentation

monitor.deadman() function

monitor.deadman() detects when a group stops reporting data. It takes a stream of tables and reports if groups have been observed since time t.

monitor.deadman() retains the most recent row from each input table and adds a dead column. If a record appears after time t, monitor.deadman() sets dead to false. Otherwise, dead is set to true.

Function type signature
(<-tables: stream[{B with _time: C}], t: A) => stream[{B with dead: bool, _time: C}] where A: Comparable, C: Comparable

For more information, see Function type signatures.

Parameters

t

(Required) Time threshold for the deadman check.

tables

Input data. Default is piped-forward data (<-).

Examples

Detect if a host hasn’t reported since a specific time

import "array"
import "influxdata/influxdb/monitor"

data =
    array.from(
        rows: [
            {_time: 2021-01-01T00:00:00Z, host: "a", _value: 1.2},
            {_time: 2021-01-01T00:01:00Z, host: "a", _value: 1.3},
            {_time: 2021-01-01T00:02:00Z, host: "a", _value: 1.4},
            {_time: 2021-01-01T00:03:00Z, host: "a", _value: 1.3},
        ],
    )
        |> group(columns: ["host"])

data
    |> monitor.deadman(t: 2021-01-01T00:05:00Z)

View example input and output

Detect if a host hasn’t reported since a relative time

Use date.add() to return a time value relative to a specified time.

import "influxdata/influxdb/monitor"
import "date"

from(bucket: "example-bucket")
    |> range(start: -10m)
    |> filter(fn: (r) => r._measurement == "example-measurement")
    |> monitor.deadman(t: date.add(d: -5m, to: now()))

Was this page helpful?

Thank you for your feedback!


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.

Read more

New in InfluxDB 3.4

Key enhancements in InfluxDB 3.4 and the InfluxDB 3 Explorer 1.2.

See the Blog Post

InfluxDB 3.4 is now available for both Core and Enterprise, which introduces offline token generation for use in automated deployments and configurable license type selection that lets you bypass the interactive license prompt. InfluxDB 3 Explorer 1.2 is also available, which includes InfluxDB cache management and other new features.

For more information, check out: