---
title: FromNode (Kapacitor TICKscript node)
description: FromNode selects a subset of the data flowing through a StreamNode. You can select which portion of the stream you want to process.
note: Auto generated by tickdoc
menu:
kapacitor_1_4:
name: FromNode
identifier: from_node
weight: 110
parent: TICKscript nodes
---
### Constructor
| Chaining Method | Description |
|:---------|:---------|
| **[from](#descr) ( )** | Creates a new stream node that can be further filtered using the Database, RetentionPolicy, Measurement and Where properties. From can be called multiple times to create multiple independent forks of the data stream. |
### Property Methods
| Setters | Description |
|:---|:---|
| **[database](#database) ( `value` `string`)** | The database name. If empty any database will be used. |
| **[groupBy](#groupby) ( `tag` `...interface{}`)** | Group the data by a set of tags. |
| **[groupByMeasurement](#groupbymeasurement) ( )** | If set will include the measurement name in the group ID. Along with any other group by dimensions. |
| **[measurement](#measurement) ( `value` `string`)** | The measurement name If empty any measurement will be used. |
| **[retentionPolicy](#retentionpolicy) ( `value` `string`)** | The retention policy name If empty any retention policy will be used. |
| **[round](#round) ( `value` `time.Duration`)** | Optional duration for rounding timestamps. Helpful to ensure data points land on specific boundaries Example: stream |from() .measurement('mydata') .round(1s) |
| **[truncate](#truncate) ( `value` `time.Duration`)** | Optional duration for truncating timestamps. Helpful to ensure data points land on specific boundaries Example: stream |from() .measurement('mydata') .truncate(1s) |
| **[where](#where) ( `lambda` `ast.LambdaNode`)** | Filter the current stream using the given expression. This expression is a Kapacitor expression. Kapacitor expressions are a superset of InfluxQL WHERE expressions. See the [expression](/kapacitor/v1.4/tick/expr/) docs for more information. |
### Chaining Methods
[Alert](/kapacitor/v1.4/nodes/from_node/#alert), [Barrier](/kapacitor/v1.4/nodes/from_node/#barrier), [Bottom](/kapacitor/v1.4/nodes/from_node/#bottom), [Combine](/kapacitor/v1.4/nodes/from_node/#combine), [Count](/kapacitor/v1.4/nodes/from_node/#count), [CumulativeSum](/kapacitor/v1.4/nodes/from_node/#cumulativesum), [Deadman](/kapacitor/v1.4/nodes/from_node/#deadman), [Default](/kapacitor/v1.4/nodes/from_node/#default), [Delete](/kapacitor/v1.4/nodes/from_node/#delete), [Derivative](/kapacitor/v1.4/nodes/from_node/#derivative), [Difference](/kapacitor/v1.4/nodes/from_node/#difference), [Distinct](/kapacitor/v1.4/nodes/from_node/#distinct), [Ec2Autoscale](/kapacitor/v1.4/nodes/from_node/#ec2autoscale), [Elapsed](/kapacitor/v1.4/nodes/from_node/#elapsed), [Eval](/kapacitor/v1.4/nodes/from_node/#eval), [First](/kapacitor/v1.4/nodes/from_node/#first), [Flatten](/kapacitor/v1.4/nodes/from_node/#flatten), [From](/kapacitor/v1.4/nodes/from_node/#from), [HoltWinters](/kapacitor/v1.4/nodes/from_node/#holtwinters), [HoltWintersWithFit](/kapacitor/v1.4/nodes/from_node/#holtwinterswithfit), [HttpOut](/kapacitor/v1.4/nodes/from_node/#httpout), [HttpPost](/kapacitor/v1.4/nodes/from_node/#httppost), [InfluxDBOut](/kapacitor/v1.4/nodes/from_node/#influxdbout), [Join](/kapacitor/v1.4/nodes/from_node/#join), [K8sAutoscale](/kapacitor/v1.4/nodes/from_node/#k8sautoscale), [KapacitorLoopback](/kapacitor/v1.4/nodes/from_node/#kapacitorloopback), [Last](/kapacitor/v1.4/nodes/from_node/#last), [Log](/kapacitor/v1.4/nodes/from_node/#log), [Max](/kapacitor/v1.4/nodes/from_node/#max), [Mean](/kapacitor/v1.4/nodes/from_node/#mean), [Median](/kapacitor/v1.4/nodes/from_node/#median), [Min](/kapacitor/v1.4/nodes/from_node/#min), [Mode](/kapacitor/v1.4/nodes/from_node/#mode), [MovingAverage](/kapacitor/v1.4/nodes/from_node/#movingaverage), [Percentile](/kapacitor/v1.4/nodes/from_node/#percentile), [Sample](/kapacitor/v1.4/nodes/from_node/#sample), [Shift](/kapacitor/v1.4/nodes/from_node/#shift), [Sideload](/kapacitor/v1.4/nodes/from_node/#sideload), [Spread](/kapacitor/v1.4/nodes/from_node/#spread), [StateCount](/kapacitor/v1.4/nodes/from_node/#statecount), [StateDuration](/kapacitor/v1.4/nodes/from_node/#stateduration), [Stats](/kapacitor/v1.4/nodes/from_node/#stats), [Stddev](/kapacitor/v1.4/nodes/from_node/#stddev), [Sum](/kapacitor/v1.4/nodes/from_node/#sum), [SwarmAutoscale](/kapacitor/v1.4/nodes/from_node/#swarmautoscale), [Top](/kapacitor/v1.4/nodes/from_node/#top), [Union](/kapacitor/v1.4/nodes/from_node/#union), [Window](/kapacitor/v1.4/nodes/from_node/#window)
### Description
A [FromNode](/kapacitor/v1.4/nodes/from_node/) selects a subset of the data flowing through a [StreamNode.](/kapacitor/v1.4/nodes/stream_node/)
The stream node allows you to select which portion of the stream you want to process.
Example:
```javascript
stream
|from()
.database('mydb')
.retentionPolicy('myrp')
.measurement('mymeasurement')
.where(lambda: "host" =~ /logger\d+/)
|window()
...
```
The above example selects only data points from the database `mydb`
and retention policy `myrp` and measurement `mymeasurement` where
the tag `host` matches the regex `logger\d+`
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.
### Database
The database name.
If empty any database will be used.
```javascript
from.database(value string)
```
### GroupBy
Group the data by a set of tags.
Can pass literal * to group by all dimensions.
Example:
```javascript
stream
|from()
.groupBy(*)
```
```javascript
from.groupBy(tag ...interface{})
```
### GroupByMeasurement
If set will include the measurement name in the group ID.
Along with any other group by dimensions.
Example:
```javascript
stream
|from()
.database('mydb')
.groupByMeasurement()
.groupBy('host')
```
The above example selects all measurements from the database 'mydb' and
then each point is grouped by the host tag and measurement name.
Thus keeping measurements in their own groups.
```javascript
from.groupByMeasurement()
```
### Measurement
The measurement name
If empty any measurement will be used.
```javascript
from.measurement(value string)
```
### RetentionPolicy
The retention policy name
If empty any retention policy will be used.
```javascript
from.retentionPolicy(value string)
```
### Round
Optional duration for rounding timestamps.
Helpful to ensure data points land on specific boundaries
Example:
```javascript
stream
|from()
.measurement('mydata')
.round(1s)
```
All incoming data will be rounded to the nearest 1 second boundary.
```javascript
from.round(value time.Duration)
```
### Truncate
Optional duration for truncating timestamps.
Helpful to ensure data points land on specific boundaries
Example:
```javascript
stream
|from()
.measurement('mydata')
.truncate(1s)
```
All incoming data will be truncated to 1 second resolution.
```javascript
from.truncate(value time.Duration)
```
### Where
Filter the current stream using the given expression.
This expression is a Kapacitor expression. Kapacitor
expressions are a superset of InfluxQL WHERE expressions.
See the [expression](/kapacitor/v1.4/tick/expr/) docs for more information.
Multiple calls to the Where method will `AND` together each expression.
Example:
```javascript
stream
|from()
.where(lambda: condition1)
.where(lambda: condition2)
```
The above is equivalent to this
Example:
```javascript
stream
|from()
.where(lambda: condition1 AND condition2)
```
NOTE: Becareful to always use `|from` if you want multiple different streams.
Example:
```javascript
var data = stream
|from()
.measurement('cpu')
var total = data
.where(lambda: "cpu" == 'cpu-total')
var others = data
.where(lambda: "cpu" != 'cpu-total')
```
The example above is equivalent to the example below,
which is obviously not what was intended.
Example:
```javascript
var data = stream
|from()
.measurement('cpu')
.where(lambda: "cpu" == 'cpu-total' AND "cpu" != 'cpu-total')
var total = data
var others = total
```
The example below will create two different streams each selecting
a different subset of the original stream.
Example:
```javascript
var data = stream
|from()
.measurement('cpu')
var total = stream
|from()
.measurement('cpu')
.where(lambda: "cpu" == 'cpu-total')
var others = stream
|from()
.measurement('cpu')
.where(lambda: "cpu" != 'cpu-total')
```
If empty then all data points are considered to match.
```javascript
from.where(lambda ast.LambdaNode)
```
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
from|alert()
```
Returns: [AlertNode](/kapacitor/v1.4/nodes/alert_node/)
### Barrier
Create a new Barrier node that emits a BarrierMessage periodically
One BarrierMessage will be emitted every period duration
```javascript
from|barrier()
```
Returns: [BarrierNode](/kapacitor/v1.4/nodes/barrier_node/)
### Bottom
Select the bottom `num` points for `field` and sort by any extra tags or fields.
```javascript
from|bottom(num int64, field string, fieldsAndTags ...string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Combine
Combine this node with itself. The data is combined on timestamp.
```javascript
from|combine(expressions ...ast.LambdaNode)
```
Returns: [CombineNode](/kapacitor/v1.4/nodes/combine_node/)
### Count
Count the number of points.
```javascript
from|count(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### CumulativeSum
Compute a cumulative sum of each point that is received.
A point is emitted for every point collected.
```javascript
from|cumulativeSum(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### 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
from|deadman(threshold float64, interval time.Duration, expr ...ast.LambdaNode)
```
Returns: [AlertNode](/kapacitor/v1.4/nodes/alert_node/)
### Default
Create a node that can set defaults for missing tags or fields.
```javascript
from|default()
```
Returns: [DefaultNode](/kapacitor/v1.4/nodes/default_node/)
### Delete
Create a node that can delete tags or fields.
```javascript
from|delete()
```
Returns: [DeleteNode](/kapacitor/v1.4/nodes/delete_node/)
### Derivative
Create a new node that computes the derivative of adjacent points.
```javascript
from|derivative(field string)
```
Returns: [DerivativeNode](/kapacitor/v1.4/nodes/derivative_node/)
### Difference
Compute the difference between points independent of elapsed time.
```javascript
from|difference(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Distinct
Produce batch of only the distinct points.
```javascript
from|distinct(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Ec2Autoscale
Create a node that can trigger autoscale events for a ec2 autoscalegroup.
```javascript
from|ec2Autoscale()
```
Returns: [Ec2AutoscaleNode](/kapacitor/v1.4/nodes/ec2_autoscale_node/)
### Elapsed
Compute the elapsed time between points
```javascript
from|elapsed(field string, unit time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### 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
from|eval(expressions ...ast.LambdaNode)
```
Returns: [EvalNode](/kapacitor/v1.4/nodes/eval_node/)
### First
Select the first point.
```javascript
from|first(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Flatten
Flatten points with similar times into a single point.
```javascript
from|flatten()
```
Returns: [FlattenNode](/kapacitor/v1.4/nodes/flatten_node/)
### From
Creates a new stream node that can be further
filtered using the Database, RetentionPolicy, Measurement and Where properties.
From can be called multiple times to create multiple
independent forks of the data stream.
Example:
```javascript
// Select the 'cpu' measurement from just the database 'mydb'
// and retention policy 'myrp'.
var cpu = stream
|from()
.database('mydb')
.retentionPolicy('myrp')
.measurement('cpu')
// Select the 'load' measurement from any database and retention policy.
var load = stream
|from()
.measurement('load')
// Join cpu and load streams and do further processing.
cpu
|join(load)
.as('cpu', 'load')
...
```
```javascript
from|from()
```
Returns: [FromNode](/kapacitor/v1.4/nodes/from_node/)
### HoltWinters
Compute the holt-winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set.
```javascript
from|holtWinters(field string, h int64, m int64, interval time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### 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
from|holtWintersWithFit(field string, h int64, m int64, interval time.Duration)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### 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/` and endpoint is
`top10`, then the data can be requested from `/kapacitor/v1/tasks//top10`.
```javascript
from|httpOut(endpoint string)
```
Returns: [HTTPOutNode](/kapacitor/v1.4/nodes/http_out_node/)
### 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
from|httpPost(url ...string)
```
Returns: [HTTPPostNode](/kapacitor/v1.4/nodes/http_post_node/)
### InfluxDBOut
Create an influxdb output node that will store the incoming data into InfluxDB.
```javascript
from|influxDBOut()
```
Returns: [InfluxDBOutNode](/kapacitor/v1.4/nodes/influx_d_b_out_node/)
### Join
Join this node with other nodes. The data is joined on timestamp.
```javascript
from|join(others ...Node)
```
Returns: [JoinNode](/kapacitor/v1.4/nodes/join_node/)
### K8sAutoscale
Create a node that can trigger autoscale events for a kubernetes cluster.
```javascript
from|k8sAutoscale()
```
Returns: [K8sAutoscaleNode](/kapacitor/v1.4/nodes/k8s_autoscale_node/)
### KapacitorLoopback
Create an kapacitor loopback node that will send data back into Kapacitor as a stream.
```javascript
from|kapacitorLoopback()
```
Returns: [KapacitorLoopbackNode](/kapacitor/v1.4/nodes/kapacitor_loopback_node/)
### Last
Select the last point.
```javascript
from|last(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Log
Create a node that logs all data it receives.
```javascript
from|log()
```
Returns: [LogNode](/kapacitor/v1.4/nodes/log_node/)
### Max
Select the maximum point.
```javascript
from|max(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Mean
Compute the mean of the data.
```javascript
from|mean(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/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)`.
```javascript
from|median(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Min
Select the minimum point.
```javascript
from|min(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Mode
Compute the mode of the data.
```javascript
from|mode(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### MovingAverage
Compute a moving average of the last window points.
No points are emitted until the window is full.
```javascript
from|movingAverage(field string, window int64)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Percentile
Select a point at the given percentile. This is a selector function, no interpolation between points is performed.
```javascript
from|percentile(field string, percentile float64)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/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.
```javascript
from|sample(rate interface{})
```
Returns: [SampleNode](/kapacitor/v1.4/nodes/sample_node/)
### Shift
Create a new node that shifts the incoming points or batches in time.
```javascript
from|shift(shift time.Duration)
```
Returns: [ShiftNode](/kapacitor/v1.4/nodes/shift_node/)
### Sideload
Create a node that can load data from external sources
```javascript
from|sideload()
```
Returns: [SideloadNode](/kapacitor/v1.4/nodes/sideload_node/)
### Spread
Compute the difference between `min` and `max` points.
```javascript
from|spread(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### StateCount
Create a node that tracks number of consecutive points in a given state.
```javascript
from|stateCount(expression ast.LambdaNode)
```
Returns: [StateCountNode](/kapacitor/v1.4/nodes/state_count_node/)
### StateDuration
Create a node that tracks duration in a given state.
```javascript
from|stateDuration(expression ast.LambdaNode)
```
Returns: [StateDurationNode](/kapacitor/v1.4/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.
```javascript
from|stats(interval time.Duration)
```
Returns: [StatsNode](/kapacitor/v1.4/nodes/stats_node/)
### Stddev
Compute the standard deviation.
```javascript
from|stddev(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Sum
Compute the sum of all values.
```javascript
from|sum(field string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### SwarmAutoscale
Create a node that can trigger autoscale events for a docker swarm cluster.
```javascript
from|swarmAutoscale()
```
Returns: [SwarmAutoscaleNode](/kapacitor/v1.4/nodes/swarm_autoscale_node/)
### Top
Select the top `num` points for `field` and sort by any extra tags or fields.
```javascript
from|top(num int64, field string, fieldsAndTags ...string)
```
Returns: [InfluxQLNode](/kapacitor/v1.4/nodes/influx_q_l_node/)
### Union
Perform the union of this node and all other given nodes.
```javascript
from|union(node ...Node)
```
Returns: [UnionNode](/kapacitor/v1.4/nodes/union_node/)
### Window
Create a new node that windows the stream by time.
NOTE: Window can only be applied to stream edges.
```javascript
from|window()
```
Returns: [WindowNode](/kapacitor/v1.4/nodes/window_node/)