856 lines
18 KiB
Markdown
856 lines
18 KiB
Markdown
---
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title: CombineNode
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description: >
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CombineNode combines data from a single node with itself. Points with the same time are grouped and then combinations are created. The size of the combinations is defined by how many expressions are given.
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note: Auto generated by tickdoc
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menu:
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kapacitor_1_6_ref:
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name: CombineNode
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identifier: combine_node
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weight: 100
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parent: nodes
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---
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The `combine` node combines data from a single node with itself.
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Points with the same time are grouped and then combinations are created.
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The size of the combinations is defined by how many expressions are given.
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Combinations are order-independent and will never include the same point multiple times.
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In the following example, data points for the `login` service are combined with
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the data points from all other services:
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```js
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stream
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|from()
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.measurement('request_latency')
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|combine(lambda: "service" == 'login', lambda: TRUE)
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.as('login', 'other')
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// points that are within 1 second are considered the same time.
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.tolerance(1s)
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// delimiter for new field and tag names
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.delimiter('.')
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// Change group by to be new other.service tag
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|groupBy('other.service')
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// Both the "value" fields from each data point have been prefixed
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// with the respective names 'login' and 'other'.
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|eval(lambda: "login.value" / "other.value")
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.as('ratio')
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...
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```
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In the following example, all combination pairs are created:
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```js
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|combine(lambda: TRUE, lambda: TRUE)
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.as('login', 'other')
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```
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In the following example, all combinations triples are created:
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```js
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|combine(lambda: TRUE, lambda: TRUE, lambda: TRUE)
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.as('login', 'other', 'another')
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```
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### Constructor
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| Chaining Method | Description |
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|:---------|:---------|
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| **combine ( `expressions` `...ast.LambdaNode`)** | Combine this node with itself. The data is combined on timestamp. |
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### Property Methods
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| Setters | Description |
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|:---|:---|
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| **[as](#as) ( `names` `...string`)** | Prefix names for all fields from the respective nodes. Each field from the parent nodes will be prefixed with the provided name and a '.'. See the example above. |
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| **[delimiter](#delimiter) ( `value` `string`)** | The delimiter between the As names and existing field an tag keys. Can be the empty string, but you are responsible for ensuring conflicts are not possible if you use the empty string. |
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| **[max](#max) ( `value` `int64`)** | Maximum number of possible combinations. Since the number of possible combinations can grow very rapidly you can set a maximum number of combinations allowed. If the max is crossed, an error is logged and the combinations are not calculated. Default: 10,000 |
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| **[quiet](#quiet) ( )** | Suppress all error logging events from this node. |
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| **[tolerance](#tolerance) ( `value` `time.Duration`)** | The maximum duration of time that two incoming points can be apart and still be considered to be equal in time. The joined data point's time will be rounded to the nearest multiple of the tolerance duration. |
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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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[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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[Trickle](#trickle),
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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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### As
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Prefix names for all fields from the respective nodes.
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Each field from the parent nodes will be prefixed with the provided name and a `.`.
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See the example above.
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The names cannot have a dot `.` character.
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```js
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combine.as(names ...string)
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```
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### Delimiter
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The delimiter between the As names and existing field an tag keys.
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Can be the empty string, but you are responsible for ensuring conflicts are not possible if you use the empty string.
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```js
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combine.delimiter(value string)
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```
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### Max
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Maximum number of possible combinations.
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Since the number of possible combinations can grow very rapidly,
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you can set a maximum number of combinations allowed.
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If the max is exceeded, an error is logged and the combinations are not calculated.
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**Default:** 10,000
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```js
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combine.max(value int64)
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```
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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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combine.quiet()
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```
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### Tolerance
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The maximum duration of time that two incoming points
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can be apart and still be considered to be equal in time.
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The joined data point's time will be rounded to the nearest
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multiple of the tolerance duration.
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```js
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combine.tolerance(value time.Duration)
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```
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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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combine|alert()
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```
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Returns: [AlertNode](/kapacitor/v1.6/nodes/alert_node/)
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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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combine|barrier()
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```
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Returns: [BarrierNode](/kapacitor/v1.6/nodes/barrier_node/)
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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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combine|bottom(num int64, field string, fieldsAndTags ...string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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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combine|changeDetect(field string)
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```
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Returns: [ChangeDetectNode](/kapacitor/v1.6/nodes/change_detect_node/)
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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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combine|combine(expressions ...ast.LambdaNode)
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```
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Returns: [CombineNode](/kapacitor/v1.6/nodes/combine_node/)
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### Count
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Count the number of points.
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```js
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combine|count(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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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combine|cumulativeSum(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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/v1.6/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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combine|deadman(threshold float64, interval time.Duration, expr ...ast.LambdaNode)
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```
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Returns: [AlertNode](/kapacitor/v1.6/nodes/alert_node/)
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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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combine|default()
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```
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Returns: [DefaultNode](/kapacitor/v1.6/nodes/default_node/)
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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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combine|delete()
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```
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Returns: [DeleteNode](/kapacitor/v1.6/nodes/delete_node/)
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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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combine|derivative(field string)
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```
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Returns: [DerivativeNode](/kapacitor/v1.6/nodes/derivative_node/)
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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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combine|difference(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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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combine|distinct(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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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combine|ec2Autoscale()
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```
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Returns: [Ec2AutoscaleNode](/kapacitor/v1.6/nodes/ec2_autoscale_node/)
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### Elapsed
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Compute the elapsed time between points.
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```js
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combine|elapsed(field string, unit time.Duration)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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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combine|eval(expressions ...ast.LambdaNode)
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```
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Returns: [EvalNode](/kapacitor/v1.6/nodes/eval_node/)
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### First
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Select the first point.
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```js
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combine|first(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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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combine|flatten()
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```
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Returns: [FlattenNode](/kapacitor/v1.6/nodes/flatten_node/)
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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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combine|groupBy(tag ...interface{})
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```
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Returns: [GroupByNode](/kapacitor/v1.6/nodes/group_by_node/)
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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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combine|holtWinters(field string, h int64, m int64, interval time.Duration)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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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combine|holtWintersWithFit(field string, h int64, m int64, interval time.Duration)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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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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combine|httpOut(endpoint string)
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```
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Returns: [HTTPOutNode](/kapacitor/v1.6/nodes/http_out_node/)
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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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combine|httpPost(url ...string)
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```
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Returns: [HTTPPostNode](/kapacitor/v1.6/nodes/http_post_node/)
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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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combine|influxDBOut()
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```
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Returns: [InfluxDBOutNode](/kapacitor/v1.6/nodes/influx_d_b_out_node/)
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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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combine|join(others ...Node)
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```
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Returns: [JoinNode](/kapacitor/v1.6/nodes/join_node/)
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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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combine|k8sAutoscale()
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```
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Returns: [K8sAutoscaleNode](/kapacitor/v1.6/nodes/k8s_autoscale_node/)
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### KapacitorLoopback
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Create an kapacitor loopback node that will send data back into Kapacitor as a stream.
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```js
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combine|kapacitorLoopback()
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```
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Returns: [KapacitorLoopbackNode](/kapacitor/v1.6/nodes/kapacitor_loopback_node/)
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### Last
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Select the last point.
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```js
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combine|last(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
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### Log
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|
|
Create a node that logs all data it receives.
|
|
|
|
|
|
```js
|
|
combine|log()
|
|
```
|
|
|
|
Returns: [LogNode](/kapacitor/v1.6/nodes/log_node/)
|
|
|
|
### Mean
|
|
|
|
Compute the mean of the data.
|
|
|
|
|
|
```js
|
|
combine|mean(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### 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
|
|
combine|median(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### Min
|
|
|
|
Select the minimum point.
|
|
|
|
|
|
```js
|
|
combine|min(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### Mode
|
|
|
|
Compute the mode of the data.
|
|
|
|
|
|
```js
|
|
combine|mode(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### MovingAverage
|
|
|
|
Compute a moving average of the last window points.
|
|
No points are emitted until the window is full.
|
|
|
|
|
|
```js
|
|
combine|movingAverage(field string, window int64)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### Percentile
|
|
|
|
Select a point at the given percentile. This is a selector function, no interpolation between points is performed.
|
|
|
|
|
|
```js
|
|
combine|percentile(field string, percentile float64)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### Sample
|
|
|
|
Create a new node that samples the incoming points or batches.
|
|
|
|
One point will be emitted every count or duration specified.
|
|
|
|
|
|
```js
|
|
combine|sample(rate interface{})
|
|
```
|
|
|
|
Returns: [SampleNode](/kapacitor/v1.6/nodes/sample_node/)
|
|
|
|
### Shift
|
|
|
|
Create a new node that shifts the incoming points or batches in time.
|
|
|
|
|
|
```js
|
|
combine|shift(shift time.Duration)
|
|
```
|
|
|
|
Returns: [ShiftNode](/kapacitor/v1.6/nodes/shift_node/)
|
|
|
|
### Sideload
|
|
|
|
Create a node that can load data from external sources.
|
|
|
|
|
|
```js
|
|
combine|sideload()
|
|
```
|
|
|
|
Returns: [SideloadNode](/kapacitor/v1.6/nodes/sideload_node/)
|
|
|
|
### Spread
|
|
|
|
Compute the difference between `min` and `max` points.
|
|
|
|
|
|
```js
|
|
combine|spread(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### StateCount
|
|
|
|
Create a node that tracks number of consecutive points in a given state.
|
|
|
|
|
|
```js
|
|
combine|stateCount(expression ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [StateCountNode](/kapacitor/v1.6/nodes/state_count_node/)
|
|
|
|
### StateDuration
|
|
|
|
Create a node that tracks duration in a given state.
|
|
|
|
|
|
```js
|
|
combine|stateDuration(expression ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [StateDurationNode](/kapacitor/v1.6/nodes/state_duration_node/)
|
|
|
|
### 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
|
|
combine|stats(interval time.Duration)
|
|
```
|
|
|
|
Returns: [StatsNode](/kapacitor/v1.6/nodes/stats_node/)
|
|
|
|
### Stddev
|
|
|
|
Compute the standard deviation.
|
|
|
|
|
|
```js
|
|
combine|stddev(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### Sum
|
|
|
|
Compute the sum of all values.
|
|
|
|
|
|
```js
|
|
combine|sum(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### SwarmAutoscale
|
|
|
|
Create a node that can trigger autoscale events for a Docker swarm cluster.
|
|
|
|
|
|
```js
|
|
combine|swarmAutoscale()
|
|
```
|
|
|
|
Returns: [SwarmAutoscaleNode](/kapacitor/v1.6/nodes/swarm_autoscale_node/)
|
|
|
|
### Top
|
|
|
|
Select the top `num` points for `field` and sort by any extra tags or fields.
|
|
|
|
|
|
```js
|
|
combine|top(num int64, field string, fieldsAndTags ...string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.6/nodes/influx_q_l_node/)
|
|
|
|
### Trickle
|
|
|
|
Create a new node that converts batch data to stream data.
|
|
|
|
```js
|
|
combine|trickle()
|
|
```
|
|
|
|
Returns: [TrickleNode](/kapacitor/v1.6/nodes/trickle_node/)
|
|
|
|
### Union
|
|
|
|
Perform the union of this node and all other given nodes.
|
|
|
|
|
|
```js
|
|
combine|union(node ...Node)
|
|
```
|
|
|
|
Returns: [UnionNode](/kapacitor/v1.6/nodes/union_node/)
|
|
|
|
### Where
|
|
|
|
Create a new node that filters the data stream by a given expression.
|
|
|
|
|
|
```js
|
|
combine|where(expression ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [WhereNode](/kapacitor/v1.6/nodes/where_node/)
|
|
|
|
### Window
|
|
|
|
Create a new node that windows the stream by time.
|
|
|
|
NOTE: Window can only be applied to stream edges.
|
|
|
|
|
|
```js
|
|
combine|window()
|
|
```
|
|
|
|
Returns: [WindowNode](/kapacitor/v1.6/nodes/window_node/)
|