883 lines
23 KiB
Markdown
883 lines
23 KiB
Markdown
---
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title: SampleNode
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description: >
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SampleNode samples points or batches. One point will be emitted every count or duration specified.
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note: Auto generated by tickdoc
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menu:
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kapacitor_1_5_ref:
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name: SampleNode
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identifier: sample_node
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weight: 230
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parent: nodes
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---
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The `sample` node samples points or batches.
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One point will be emitted every count or duration specified.
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Example:
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```js
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stream
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|sample(3)
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```
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Keep every third data point or batch.
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Example:
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```js
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stream
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|sample(10s)
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```
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Keep only samples that land on the 10s boundary.
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See [FromNode.Truncate,](/kapacitor/v1.5/nodes/from_node/#truncate) [QueryNode.GroupBy](/kapacitor/v1.5/nodes/query_node/#groupby) time or [WindowNode.Align](/kapacitor/v1.5/nodes/window_node/#align)
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for ensuring data is aligned with a boundary.
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### Constructor
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| Chaining Method | Description |
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|:---------|:---------|
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| **sample ( `rate` `interface{}`)** | Create a new node that samples the incoming points or batches. |
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### Property Methods
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| Setters | Description |
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|:---|:---|
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| **[quiet](#quiet) ( )** | Suppress all error logging events from this node. |
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### Chaining Methods
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[Alert](#alert),
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[Barrier](#barrier),
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[Bottom](#bottom),
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[ChangeDetect](#changedetect),
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[Combine](#combine),
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[Count](#count),
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[CumulativeSum](#cumulativesum),
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[Deadman](#deadman),
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[Default](#default),
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[Delete](#delete),
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[Derivative](#derivative),
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[Difference](#difference),
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[Distinct](#distinct),
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[Ec2Autoscale](#ec2autoscale),
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[Elapsed](#elapsed),
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[Eval](#eval),
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[First](#first),
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[Flatten](#flatten),
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[GroupBy](#groupby),
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[HoltWinters](#holtwinters),
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[HoltWintersWithFit](#holtwinterswithfit),
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[HttpOut](#httpout),
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[HttpPost](#httppost),
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[InfluxDBOut](#influxdbout),
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[Join](#join),
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[K8sAutoscale](#k8sautoscale),
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[KapacitorLoopback](#kapacitorloopback),
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[Last](#last),
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[Log](#log),
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[Max](#max),
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[Mean](#mean),
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[Median](#median),
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[Min](#min),
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[Mode](#mode),
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[MovingAverage](#movingaverage),
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[Percentile](#percentile),
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[Sample](#sample),
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[Shift](#shift),
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[Sideload](#sideload),
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[Spread](#spread),
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[StateCount](#statecount),
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[StateDuration](#stateduration),
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[Stats](#stats),
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[Stddev](#stddev),
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[Sum](#sum),
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[SwarmAutoscale](#swarmautoscale),
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[Top](#top),
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[Union](#union),
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[Where](#where),
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[Window](#window)
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---
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## Properties
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Property methods modify state on the calling node.
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They do not add another node to the pipeline, and always return a reference to the calling node.
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Property methods are marked using the `.` operator.
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### Quiet
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Suppress all error logging events from this node.
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```js
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sample.quiet()
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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## Chaining Methods
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Chaining methods create a new node in the pipeline as a child of the calling node.
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They do not modify the calling node.
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Chaining methods are marked using the `|` operator.
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### Alert
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Create an alert node, which can trigger alerts.
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```js
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sample|alert()
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```
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Returns: [AlertNode](/kapacitor/v1.5/nodes/alert_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Barrier
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Create a new Barrier node that emits a BarrierMessage periodically.
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One BarrierMessage will be emitted every period duration.
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```js
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sample|barrier()
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```
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Returns: [BarrierNode](/kapacitor/v1.5/nodes/barrier_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Bottom
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Select the bottom `num` points for `field` and sort by any extra tags or fields.
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```js
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sample|bottom(num int64, field string, fieldsAndTags ...string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### ChangeDetect
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Create a new node that only emits new points if different from the previous point.
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```js
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sample|changeDetect(field string)
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```
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Returns: [ChangeDetectNode](/kapacitor/v1.5/nodes/change_detect_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Combine
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Combine this node with itself. The data is combined on timestamp.
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```js
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sample|combine(expressions ...ast.LambdaNode)
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```
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Returns: [CombineNode](/kapacitor/v1.5/nodes/combine_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Count
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Count the number of points.
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```js
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sample|count(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### CumulativeSum
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Compute a cumulative sum of each point that is received.
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A point is emitted for every point collected.
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```js
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sample|cumulativeSum(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Deadman
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Helper function for creating an alert on low throughput, a.k.a. deadman's switch.
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- Threshold: trigger alert if throughput drops below threshold in points/interval.
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- Interval: how often to check the throughput.
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- Expressions: optional list of expressions to also evaluate. Useful for time of day alerting.
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Example:
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```js
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var data = stream
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// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
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data
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|deadman(100.0, 10s)
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//Do normal processing of data
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data...
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```
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The above is equivalent to this example:
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```js
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var data = stream
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|from()...
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// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
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data
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|stats(10s)
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.align()
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|derivative('emitted')
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.unit(10s)
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.nonNegative()
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|alert()
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.id('node \'stream0\' in task \'{{ .TaskName }}\'')
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.message('{{ .ID }} is {{ if eq .Level "OK" }}alive{{ else }}dead{{ end }}: {{ index .Fields "emitted" | printf "%0.3f" }} points/10s.')
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.crit(lambda: "emitted" <= 100.0)
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//Do normal processing of data
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data...
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```
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The `id` and `message` alert properties can be configured globally via the 'deadman' configuration section.
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Since the [AlertNode](/kapacitor/v1.5/nodes/alert_node/) is the last piece it can be further modified as usual.
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Example:
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```js
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var data = stream
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// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
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data
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|deadman(100.0, 10s)
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.slack()
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.channel('#dead_tasks')
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//Do normal processing of data
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data...
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```
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You can specify additional lambda expressions to further constrain when the deadman's switch is triggered.
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Example:
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```js
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var data = stream
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// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
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// Only trigger the alert if the time of day is between 8am-5pm.
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data
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|deadman(100.0, 10s, lambda: hour("time") >= 8 AND hour("time") <= 17)
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//Do normal processing of data
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data...
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```
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```js
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sample|deadman(threshold float64, interval time.Duration, expr ...ast.LambdaNode)
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```
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Returns: [AlertNode](/kapacitor/v1.5/nodes/alert_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Default
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Create a node that can set defaults for missing tags or fields.
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```js
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sample|default()
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```
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Returns: [DefaultNode](/kapacitor/v1.5/nodes/default_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Delete
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Create a node that can delete tags or fields.
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```js
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sample|delete()
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```
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Returns: [DeleteNode](/kapacitor/v1.5/nodes/delete_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Derivative
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Create a new node that computes the derivative of adjacent points.
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```js
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sample|derivative(field string)
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```
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Returns: [DerivativeNode](/kapacitor/v1.5/nodes/derivative_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Difference
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Compute the difference between points independent of elapsed time.
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```js
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sample|difference(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Distinct
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Produce batch of only the distinct points.
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```js
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sample|distinct(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Ec2Autoscale
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Create a node that can trigger autoscale events for a ec2 autoscalegroup.
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```js
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sample|ec2Autoscale()
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```
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Returns: [Ec2AutoscaleNode](/kapacitor/v1.5/nodes/ec2_autoscale_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Elapsed
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Compute the elapsed time between points.
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```js
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sample|elapsed(field string, unit time.Duration)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Eval
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Create an eval node that will evaluate the given transformation function to each data point.
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A list of expressions may be provided and will be evaluated in the order they are given.
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The results are available to later expressions.
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```js
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sample|eval(expressions ...ast.LambdaNode)
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```
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Returns: [EvalNode](/kapacitor/v1.5/nodes/eval_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### First
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Select the first point.
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```js
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sample|first(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Flatten
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Flatten points with similar times into a single point.
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```js
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sample|flatten()
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```
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Returns: [FlattenNode](/kapacitor/v1.5/nodes/flatten_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### GroupBy
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Group the data by a set of tags.
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Can pass literal * to group by all dimensions.
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Example:
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```js
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|groupBy(*)
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```
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```js
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sample|groupBy(tag ...interface{})
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```
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Returns: [GroupByNode](/kapacitor/v1.5/nodes/group_by_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### HoltWinters
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Compute the Holt-Winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set.
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```js
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sample|holtWinters(field string, h int64, m int64, interval time.Duration)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### HoltWintersWithFit
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Compute the Holt-Winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set.
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This method also outputs all the points used to fit the data in addition to the forecasted data.
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```js
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sample|holtWintersWithFit(field string, h int64, m int64, interval time.Duration)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### HttpOut
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Create an HTTP output node that caches the most recent data it has received.
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The cached data is available at the given endpoint.
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The endpoint is the relative path from the API endpoint of the running task.
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For example, if the task endpoint is at `/kapacitor/v1/tasks/<task_id>` and endpoint is
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`top10`, then the data can be requested from `/kapacitor/v1/tasks/<task_id>/top10`.
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```js
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sample|httpOut(endpoint string)
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```
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Returns: [HTTPOutNode](/kapacitor/v1.5/nodes/http_out_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### HttpPost
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Creates an HTTP Post node that POSTS received data to the provided HTTP endpoint.
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HttpPost expects 0 or 1 arguments. If 0 arguments are provided, you must specify an
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endpoint property method.
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```js
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sample|httpPost(url ...string)
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```
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Returns: [HTTPPostNode](/kapacitor/v1.5/nodes/http_post_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### InfluxDBOut
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Create an influxdb output node that will store the incoming data into InfluxDB.
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```js
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sample|influxDBOut()
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```
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Returns: [InfluxDBOutNode](/kapacitor/v1.5/nodes/influx_d_b_out_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Join
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Join this node with other nodes. The data is joined on timestamp.
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```js
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sample|join(others ...Node)
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```
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Returns: [JoinNode](/kapacitor/v1.5/nodes/join_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### K8sAutoscale
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Create a node that can trigger autoscale events for a kubernetes cluster.
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```js
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sample|k8sAutoscale()
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```
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Returns: [K8sAutoscaleNode](/kapacitor/v1.5/nodes/k8s_autoscale_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### KapacitorLoopback
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|
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|
Create an kapacitor loopback node that will send data back into Kapacitor as a stream.
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|
|
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|
```js
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|
sample|kapacitorLoopback()
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|
```
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|
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|
Returns: [KapacitorLoopbackNode](/kapacitor/v1.5/nodes/kapacitor_loopback_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Last
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|
Select the last point.
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|
|
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|
```js
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|
sample|last(field string)
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|
```
|
|
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|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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|
### Log
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|
|
|
Create a node that logs all data it receives.
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|
|
|
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|
```js
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|
sample|log()
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|
```
|
|
|
|
Returns: [LogNode](/kapacitor/v1.5/nodes/log_node/)
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|
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|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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|
### Max
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|
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|
Select the maximum point.
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|
|
|
|
|
```js
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|
sample|max(field string)
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|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Mean
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|
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|
Compute the mean of the data.
|
|
|
|
|
|
```js
|
|
sample|mean(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Median
|
|
|
|
Compute the median of the data.
|
|
|
|
> **Note:** This method is not a selector.
|
|
If you want the median point, use `.percentile(field, 50.0)`.
|
|
|
|
|
|
```js
|
|
sample|median(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Min
|
|
|
|
Select the minimum point.
|
|
|
|
|
|
```js
|
|
sample|min(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Mode
|
|
|
|
Compute the mode of the data.
|
|
|
|
|
|
```js
|
|
sample|mode(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### MovingAverage
|
|
|
|
Compute a moving average of the last window points.
|
|
No points are emitted until the window is full.
|
|
|
|
|
|
```js
|
|
sample|movingAverage(field string, window int64)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Percentile
|
|
|
|
Select a point at the given percentile. This is a selector function, no interpolation between points is performed.
|
|
|
|
|
|
```js
|
|
sample|percentile(field string, percentile float64)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Sample
|
|
|
|
Create a new node that samples the incoming points or batches.
|
|
|
|
One point will be emitted every count or duration specified.
|
|
|
|
|
|
```js
|
|
sample|sample(rate interface{})
|
|
```
|
|
|
|
Returns: [SampleNode](/kapacitor/v1.5/nodes/sample_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Shift
|
|
|
|
Create a new node that shifts the incoming points or batches in time.
|
|
|
|
|
|
```js
|
|
sample|shift(shift time.Duration)
|
|
```
|
|
|
|
Returns: [ShiftNode](/kapacitor/v1.5/nodes/shift_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Sideload
|
|
|
|
Create a node that can load data from external sources.
|
|
|
|
|
|
```js
|
|
sample|sideload()
|
|
```
|
|
|
|
Returns: [SideloadNode](/kapacitor/v1.5/nodes/sideload_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Spread
|
|
|
|
Compute the difference between `min` and `max` points.
|
|
|
|
|
|
```js
|
|
sample|spread(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### StateCount
|
|
|
|
Create a node that tracks number of consecutive points in a given state.
|
|
|
|
|
|
```js
|
|
sample|stateCount(expression ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [StateCountNode](/kapacitor/v1.5/nodes/state_count_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### StateDuration
|
|
|
|
Create a node that tracks duration in a given state.
|
|
|
|
|
|
```js
|
|
sample|stateDuration(expression ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [StateDurationNode](/kapacitor/v1.5/nodes/state_duration_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Stats
|
|
|
|
Create a new stream of data that contains the internal statistics of the node.
|
|
The interval represents how often to emit the statistics based on real time.
|
|
This means the interval time is independent of the times of the data points the source node is receiving.
|
|
|
|
|
|
```js
|
|
sample|stats(interval time.Duration)
|
|
```
|
|
|
|
Returns: [StatsNode](/kapacitor/v1.5/nodes/stats_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Stddev
|
|
|
|
Compute the standard deviation.
|
|
|
|
|
|
```js
|
|
sample|stddev(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Sum
|
|
|
|
Compute the sum of all values.
|
|
|
|
|
|
```js
|
|
sample|sum(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### SwarmAutoscale
|
|
|
|
Create a node that can trigger autoscale events for a Docker swarm cluster.
|
|
|
|
|
|
```js
|
|
sample|swarmAutoscale()
|
|
```
|
|
|
|
Returns: [SwarmAutoscaleNode](/kapacitor/v1.5/nodes/swarm_autoscale_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Top
|
|
|
|
Select the top `num` points for `field` and sort by any extra tags or fields.
|
|
|
|
|
|
```js
|
|
sample|top(num int64, field string, fieldsAndTags ...string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Union
|
|
|
|
Perform the union of this node and all other given nodes.
|
|
|
|
|
|
```js
|
|
sample|union(node ...Node)
|
|
```
|
|
|
|
Returns: [UnionNode](/kapacitor/v1.5/nodes/union_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Where
|
|
|
|
Create a new node that filters the data stream by a given expression.
|
|
|
|
|
|
```js
|
|
sample|where(expression ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [WhereNode](/kapacitor/v1.5/nodes/where_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Window
|
|
|
|
Create a new node that windows the stream by time.
|
|
|
|
NOTE: Window can only be applied to stream edges.
|
|
|
|
|
|
```js
|
|
sample|window()
|
|
```
|
|
|
|
Returns: [WindowNode](/kapacitor/v1.5/nodes/window_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|