docs-v2/content/kapacitor/v1.4/nodes/default_node.md

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---
title: DefaultNode (Kapacitor TICKscript node)
description: DefaultNode sets defaults of fields and tags on data points.
note: Auto generated by tickdoc
menu:
kapacitor_1_4:
name: DefaultNode
identifier: default_node
weight: 50
parent: TICKscript nodes
---
### Constructor
| Chaining Method | Description |
|:---------|:---------|
| **[default](#descr) ( )** | Create a node that can set defaults for missing tags or fields. |
### Property Methods
| Setters | Description |
|:---|:---|
| **[field](#field) ( `name` `string`, `value` `interface{}`)** | Define a field default. |
| **[tag](#tag) ( `name` `string`, `value` `string`)** | Define a tag default. |
### Chaining Methods
[Alert](/kapacitor/v1.4/nodes/default_node/#alert), [Barrier](/kapacitor/v1.4/nodes/default_node/#barrier), [Bottom](/kapacitor/v1.4/nodes/default_node/#bottom), [Combine](/kapacitor/v1.4/nodes/default_node/#combine), [Count](/kapacitor/v1.4/nodes/default_node/#count), [CumulativeSum](/kapacitor/v1.4/nodes/default_node/#cumulativesum), [Deadman](/kapacitor/v1.4/nodes/default_node/#deadman), [Default](/kapacitor/v1.4/nodes/default_node/#default), [Delete](/kapacitor/v1.4/nodes/default_node/#delete), [Derivative](/kapacitor/v1.4/nodes/default_node/#derivative), [Difference](/kapacitor/v1.4/nodes/default_node/#difference), [Distinct](/kapacitor/v1.4/nodes/default_node/#distinct), [Ec2Autoscale](/kapacitor/v1.4/nodes/default_node/#ec2autoscale), [Elapsed](/kapacitor/v1.4/nodes/default_node/#elapsed), [Eval](/kapacitor/v1.4/nodes/default_node/#eval), [First](/kapacitor/v1.4/nodes/default_node/#first), [Flatten](/kapacitor/v1.4/nodes/default_node/#flatten), [GroupBy](/kapacitor/v1.4/nodes/default_node/#groupby), [HoltWinters](/kapacitor/v1.4/nodes/default_node/#holtwinters), [HoltWintersWithFit](/kapacitor/v1.4/nodes/default_node/#holtwinterswithfit), [HttpOut](/kapacitor/v1.4/nodes/default_node/#httpout), [HttpPost](/kapacitor/v1.4/nodes/default_node/#httppost), [InfluxDBOut](/kapacitor/v1.4/nodes/default_node/#influxdbout), [Join](/kapacitor/v1.4/nodes/default_node/#join), [K8sAutoscale](/kapacitor/v1.4/nodes/default_node/#k8sautoscale), [KapacitorLoopback](/kapacitor/v1.4/nodes/default_node/#kapacitorloopback), [Last](/kapacitor/v1.4/nodes/default_node/#last), [Log](/kapacitor/v1.4/nodes/default_node/#log), [Max](/kapacitor/v1.4/nodes/default_node/#max), [Mean](/kapacitor/v1.4/nodes/default_node/#mean), [Median](/kapacitor/v1.4/nodes/default_node/#median), [Min](/kapacitor/v1.4/nodes/default_node/#min), [Mode](/kapacitor/v1.4/nodes/default_node/#mode), [MovingAverage](/kapacitor/v1.4/nodes/default_node/#movingaverage), [Percentile](/kapacitor/v1.4/nodes/default_node/#percentile), [Sample](/kapacitor/v1.4/nodes/default_node/#sample), [Shift](/kapacitor/v1.4/nodes/default_node/#shift), [Sideload](/kapacitor/v1.4/nodes/default_node/#sideload), [Spread](/kapacitor/v1.4/nodes/default_node/#spread), [StateCount](/kapacitor/v1.4/nodes/default_node/#statecount), [StateDuration](/kapacitor/v1.4/nodes/default_node/#stateduration), [Stats](/kapacitor/v1.4/nodes/default_node/#stats), [Stddev](/kapacitor/v1.4/nodes/default_node/#stddev), [Sum](/kapacitor/v1.4/nodes/default_node/#sum), [SwarmAutoscale](/kapacitor/v1.4/nodes/default_node/#swarmautoscale), [Top](/kapacitor/v1.4/nodes/default_node/#top), [Union](/kapacitor/v1.4/nodes/default_node/#union), [Where](/kapacitor/v1.4/nodes/default_node/#where), [Window](/kapacitor/v1.4/nodes/default_node/#window)
<a id='descr'/><hr/><br/>
### Description
Sets defaults of fields and tags on data points.
Example:
```javascript
stream
|default()
.field('value', 0.0)
.tag('host', '')
```
The above example will set the field `value` to float64(0) if it does not already exist
It will also set the tag `host` to string("") if it does not already exist.
Available Statistics:
* fields_defaulted -- number of fields that were missing
* tags_defaulted -- number of tags that were missing
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Properties
----------
Property methods modify state on the calling node.
They do not add another node to the pipeline, and always return a reference to the calling node.
Property methods are marked using the `.` operator.
### Field
Define a field default.
```javascript
default.field(name string, value interface{})
```
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### Tag
Define a tag default.
```javascript
default.tag(name string, value string)
```
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Chaining Methods
----------------
Chaining methods create a new node in the pipeline as a child of the calling node.
They do not modify the calling node.
Chaining methods are marked using the `|` operator.
### Alert
Create an alert node, which can trigger alerts.
```javascript
default|alert()
```
Returns: [AlertNode](/kapacitor/v1.4/nodes/alert_node/)
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### Barrier
Create a new Barrier node that emits a BarrierMessage periodically
One BarrierMessage will be emitted every period duration
```javascript
default|barrier()
```
Returns: [BarrierNode](/kapacitor/v1.4/nodes/barrier_node/)
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### Bottom
Select the bottom `num` points for `field` and sort by any extra tags or fields.
```javascript
default|bottom(num int64, field string, fieldsAndTags ...string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Combine
Combine this node with itself. The data is combined on timestamp.
```javascript
default|combine(expressions ...ast.LambdaNode)
```
Returns: [CombineNode](/kapacitor/v1.4/nodes/combine_node/)
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### Count
Count the number of points.
```javascript
default|count(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### CumulativeSum
Compute a cumulative sum of each point that is received.
A point is emitted for every point collected.
```javascript
default|cumulativeSum(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Deadman
Helper function for creating an alert on low throughput, a.k.a. deadman's switch.
- Threshold -- trigger alert if throughput drops below threshold in points/interval.
- Interval -- how often to check the throughput.
- Expressions -- optional list of expressions to also evaluate. Useful for time of day alerting.
Example:
```javascript
var data = stream
|from()...
// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
data
|deadman(100.0, 10s)
//Do normal processing of data
data...
```
The above is equivalent to this
Example:
```javascript
var data = stream
|from()...
// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
data
|stats(10s)
.align()
|derivative('emitted')
.unit(10s)
.nonNegative()
|alert()
.id('node \'stream0\' in task \'{{ .TaskName }}\'')
.message('{{ .ID }} is {{ if eq .Level "OK" }}alive{{ else }}dead{{ end }}: {{ index .Fields "emitted" | printf "%0.3f" }} points/10s.')
.crit(lambda: "emitted" <= 100.0)
//Do normal processing of data
data...
```
The `id` and `message` alert properties can be configured globally via the 'deadman' configuration section.
Since the [AlertNode](/kapacitor/v1.4/nodes/alert_node/) is the last piece it can be further modified as usual.
Example:
```javascript
var data = stream
|from()...
// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
data
|deadman(100.0, 10s)
.slack()
.channel('#dead_tasks')
//Do normal processing of data
data...
```
You can specify additional lambda expressions to further constrain when the deadman's switch is triggered.
Example:
```javascript
var data = stream
|from()...
// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
// Only trigger the alert if the time of day is between 8am-5pm.
data
|deadman(100.0, 10s, lambda: hour("time") >= 8 AND hour("time") <= 17)
//Do normal processing of data
data...
```
```javascript
default|deadman(threshold float64, interval time.Duration, expr ...ast.LambdaNode)
```
Returns: [AlertNode](/kapacitor/v1.4/nodes/alert_node/)
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### Default
Create a node that can set defaults for missing tags or fields.
```javascript
default|default()
```
Returns: [DefaultNode](/kapacitor/v1.4/nodes/default_node/)
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### Delete
Create a node that can delete tags or fields.
```javascript
default|delete()
```
Returns: [DeleteNode](/kapacitor/v1.4/nodes/delete_node/)
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### Derivative
Create a new node that computes the derivative of adjacent points.
```javascript
default|derivative(field string)
```
Returns: [DerivativeNode](/kapacitor/v1.4/nodes/derivative_node/)
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### Difference
Compute the difference between points independent of elapsed time.
```javascript
default|difference(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Distinct
Produce batch of only the distinct points.
```javascript
default|distinct(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Ec2Autoscale
Create a node that can trigger autoscale events for a ec2 autoscalegroup.
```javascript
default|ec2Autoscale()
```
Returns: [Ec2AutoscaleNode](/kapacitor/v1.4/nodes/ec2_autoscale_node/)
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### Elapsed
Compute the elapsed time between points
```javascript
default|elapsed(field string, unit time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Eval
Create an eval node that will evaluate the given transformation function to each data point.
A list of expressions may be provided and will be evaluated in the order they are given.
The results are available to later expressions.
```javascript
default|eval(expressions ...ast.LambdaNode)
```
Returns: [EvalNode](/kapacitor/v1.4/nodes/eval_node/)
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### First
Select the first point.
```javascript
default|first(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Flatten
Flatten points with similar times into a single point.
```javascript
default|flatten()
```
Returns: [FlattenNode](/kapacitor/v1.4/nodes/flatten_node/)
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### GroupBy
Group the data by a set of tags.
Can pass literal * to group by all dimensions.
Example:
```javascript
|groupBy(*)
```
```javascript
default|groupBy(tag ...interface{})
```
Returns: [GroupByNode](/kapacitor/v1.4/nodes/group_by_node/)
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### HoltWinters
Compute the holt-winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set.
```javascript
default|holtWinters(field string, h int64, m int64, interval time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### HoltWintersWithFit
Compute the holt-winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set.
This method also outputs all the points used to fit the data in addition to the forecasted data.
```javascript
default|holtWintersWithFit(field string, h int64, m int64, interval time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### HttpOut
Create an HTTP output node that caches the most recent data it has received.
The cached data is available at the given endpoint.
The endpoint is the relative path from the API endpoint of the running task.
For example, if the task endpoint is at `/kapacitor/v1/tasks/<task_id>` and endpoint is
`top10`, then the data can be requested from `/kapacitor/v1/tasks/<task_id>/top10`.
```javascript
default|httpOut(endpoint string)
```
Returns: [HTTPOutNode](/kapacitor/v1.4/nodes/http_out_node/)
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### HttpPost
Creates an HTTP Post node that POSTS received data to the provided HTTP endpoint.
HttpPost expects 0 or 1 arguments. If 0 arguments are provided, you must specify an
endpoint property method.
```javascript
default|httpPost(url ...string)
```
Returns: [HTTPPostNode](/kapacitor/v1.4/nodes/http_post_node/)
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### InfluxDBOut
Create an influxdb output node that will store the incoming data into InfluxDB.
```javascript
default|influxDBOut()
```
Returns: [InfluxDBOutNode](/kapacitor/v1.4/nodes/influx_d_b_out_node/)
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### Join
Join this node with other nodes. The data is joined on timestamp.
```javascript
default|join(others ...Node)
```
Returns: [JoinNode](/kapacitor/v1.4/nodes/join_node/)
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### K8sAutoscale
Create a node that can trigger autoscale events for a kubernetes cluster.
```javascript
default|k8sAutoscale()
```
Returns: [K8sAutoscaleNode](/kapacitor/v1.4/nodes/k8s_autoscale_node/)
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### KapacitorLoopback
Create an kapacitor loopback node that will send data back into Kapacitor as a stream.
```javascript
default|kapacitorLoopback()
```
Returns: [KapacitorLoopbackNode](/kapacitor/v1.4/nodes/kapacitor_loopback_node/)
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### Last
Select the last point.
```javascript
default|last(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Log
Create a node that logs all data it receives.
```javascript
default|log()
```
Returns: [LogNode](/kapacitor/v1.4/nodes/log_node/)
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### Max
Select the maximum point.
```javascript
default|max(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Mean
Compute the mean of the data.
```javascript
default|mean(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### 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)`.
```javascript
default|median(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Min
Select the minimum point.
```javascript
default|min(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Mode
Compute the mode of the data.
```javascript
default|mode(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### MovingAverage
Compute a moving average of the last window points.
No points are emitted until the window is full.
```javascript
default|movingAverage(field string, window int64)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Percentile
Select a point at the given percentile. This is a selector function, no interpolation between points is performed.
```javascript
default|percentile(field string, percentile float64)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Sample
Create a new node that samples the incoming points or batches.
One point will be emitted every count or duration specified.
```javascript
default|sample(rate interface{})
```
Returns: [SampleNode](/kapacitor/v1.4/nodes/sample_node/)
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### Shift
Create a new node that shifts the incoming points or batches in time.
```javascript
default|shift(shift time.Duration)
```
Returns: [ShiftNode](/kapacitor/v1.4/nodes/shift_node/)
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### Sideload
Create a node that can load data from external sources
```javascript
default|sideload()
```
Returns: [SideloadNode](/kapacitor/v1.4/nodes/sideload_node/)
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### Spread
Compute the difference between `min` and `max` points.
```javascript
default|spread(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### StateCount
Create a node that tracks number of consecutive points in a given state.
```javascript
default|stateCount(expression ast.LambdaNode)
```
Returns: [StateCountNode](/kapacitor/v1.4/nodes/state_count_node/)
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### StateDuration
Create a node that tracks duration in a given state.
```javascript
default|stateDuration(expression ast.LambdaNode)
```
Returns: [StateDurationNode](/kapacitor/v1.4/nodes/state_duration_node/)
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### 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.
```javascript
default|stats(interval time.Duration)
```
Returns: [StatsNode](/kapacitor/v1.4/nodes/stats_node/)
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### Stddev
Compute the standard deviation.
```javascript
default|stddev(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Sum
Compute the sum of all values.
```javascript
default|sum(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### SwarmAutoscale
Create a node that can trigger autoscale events for a docker swarm cluster.
```javascript
default|swarmAutoscale()
```
Returns: [SwarmAutoscaleNode](/kapacitor/v1.4/nodes/swarm_autoscale_node/)
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### Top
Select the top `num` points for `field` and sort by any extra tags or fields.
```javascript
default|top(num int64, field string, fieldsAndTags ...string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
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### Union
Perform the union of this node and all other given nodes.
```javascript
default|union(node ...Node)
```
Returns: [UnionNode](/kapacitor/v1.4/nodes/union_node/)
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### Where
Create a new node that filters the data stream by a given expression.
```javascript
default|where(expression ast.LambdaNode)
```
Returns: [WhereNode](/kapacitor/v1.4/nodes/where_node/)
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### Window
Create a new node that windows the stream by time.
NOTE: Window can only be applied to stream edges.
```javascript
default|window()
```
Returns: [WindowNode](/kapacitor/v1.4/nodes/window_node/)
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