--- title: QueryFluxNode description: QueryFluxNode defines a source and a schedule for processing batch data. The data is queried from an InfluxDB bucket and then passed into the data pipeline. url: https://docs.influxdata.com/kapacitor/v1/reference/nodes/query_flux_node/ estimated_tokens: 12300 product: Kapacitor version: v1 --- # QueryFluxNode The `queryFlux` node defines a source and a schedule for processing batch data. The data is queried from an InfluxDB bucket and then passed into the data pipeline. ##### Example The following example queries InfluxDB every 20 seconds and returns data from the last minute. ```js batch |queryFlux(''' from(bucket: "example-bucket") |> range(start: -1m) |> filter(fn: (r) => r._measurement == "example-measurement" and r._field == "example-field" ) ''') .period(1m) .every(20s) ``` ### Constructor | Chaining Method | Description | | --- | --- | | queryFlux( queryStr string) | Flux query to execute. | ### Property Methods | Setters | Description | | --- | --- | | align( ) | Align start and end times with the every value. Does not apply if cron is used. | | cluster( value string) | The name of a configured InfluxDB cluster. If empty the default cluster will be used. | | cron( value string) | Define a schedule using cron syntax. Mutually exclusive with the every property. | | every( value time.Duration) | How often to query InfluxDB. Mutually exclusive with the cron property. | | offset( value time.Duration) | How far back in time to query from the current time. | | org( value string) | InfluxDB Cloud or 2.x organization name. | | orgID( value string) | InfluxDB Cloud or 2.x organization ID. | | period( value time.Duration) | The period or length of time that will be queried from InfluxDB. | | quiet( ) | Suppress all error logging events from this node. | ### Chaining Methods [Alert](#alert), [Barrier](#barrier), [Bottom](#bottom), [ChangeDetect](#changedetect), [Combine](#combine), [Count](#count), [CumulativeSum](#cumulativesum), [Deadman](#deadman), [Default](#default), [Delete](#delete), [Derivative](#derivative), [Difference](#difference), [Distinct](#distinct), [Ec2Autoscale](#ec2autoscale), [Elapsed](#elapsed), [Eval](#eval), [First](#first), [Flatten](#flatten), [HoltWinters](#holtwinters), [HoltWintersWithFit](#holtwinterswithfit), [HttpOut](#httpout), [HttpPost](#httppost), [InfluxDBOut](#influxdbout), [Join](#join), [K8sAutoscale](#k8sautoscale), [KapacitorLoopback](#kapacitorloopback), [Last](#last), [Log](#log), [Max](#max), [Mean](#mean), [Median](#median), [Min](#min), [Mode](#mode), [MovingAverage](#movingaverage), [Percentile](#percentile), [Sample](#sample), [Shift](#shift), [Sideload](#sideload), [Spread](#spread), [StateCount](#statecount), [StateDuration](#stateduration), [Stats](#stats), [Stddev](#stddev), [Sum](#sum), [SwarmAutoscale](#swarmautoscale), [Top](#top), [Trickle](#trickle), [Union](#union), [Where](#where), [Window](#window) ## 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. ### Align Align start and stop times for queries with even boundaries of the [QueryFluxNode.Every](/kapacitor/v1/reference/nodes/query_node/#every) property. Does not apply if using the [QueryFluxNode.Cron](/kapacitor/v1/reference/nodes/query_node/#cron) property. ```js queryFlux.align() ``` ### Cluster The name of a configured InfluxDB cluster. If empty, the default cluster is used. ```js queryFlux.cluster(value string) ``` ### Cron Define a schedule using a cron syntax. The specific cron implementation is documented here: https://github.com/gorhill/cronexpr#implementation The Cron property is mutually exclusive with the Every property. ```js queryFlux.cron(value string) ``` ### Every How often to query InfluxDB. The Every property is mutually exclusive with the Cron property. ```js queryFlux.every(value time.Duration) ``` ### Offset How far back in time to query from the current time. For example, with an `offset` of 2 hours and an `every` of 5m, Kapacitor will query InfluxDB every 5 minutes for the window of data 2 hours ago. This applies to Cron schedules as well. If the cron specifies to run every Sunday at 1 AM and the Offset is 1 hour. Then at 1 AM on Sunday the data from 12 AM will be queried. ```js queryFlux.offset(value time.Duration) ``` ### Period The period or length of time queried from InfluxDB. ```js queryFlux.period(value time.Duration) ``` ### Org The InfluxDB Cloud or 2.x organization name to query. If empty, the default `org` is used. ```js queryFlux.org(value string) ``` ### OrgID The InfluxDB Cloud or 2.x organization ID to query. If empty, the default `orgID` is used. ```js queryFlux.orgID(value string) ``` ### Quiet Suppress all error logging events from this node. ```js queryFlux.quiet() ``` ## 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. ```js queryFlux|alert() ``` Returns: [AlertNode](/kapacitor/v1/reference/nodes/alert_node/) ### Barrier Create a new Barrier node that emits a BarrierMessage periodically. One BarrierMessage will be emitted every period duration. ```js queryFlux|barrier() ``` Returns: [BarrierNode](/kapacitor/v1/reference/nodes/barrier_node/) ### Bottom Select the bottom `num` points for `field` and sort by any extra tags or fields. ```js queryFlux|bottom(num int64, field string, fieldsAndTags ...string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### ChangeDetect Create a new node that only emits new points if different from the previous point. ```js queryFlux|changeDetect(field string) ``` Returns: [ChangeDetectNode](/kapacitor/v1/reference/nodes/change_detect_node/) ### Combine Combine this node with itself. The data is combined on timestamp. ```js queryFlux|combine(expressions ...ast.LambdaNode) ``` Returns: [CombineNode](/kapacitor/v1/reference/nodes/combine_node/) ### Count Count the number of points. ```js queryFlux|count(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### CumulativeSum Compute a cumulative sum of each point that is received. A point is emitted for every point collected. ```js queryFlux|cumulativeSum(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/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: ```js var data = batch |queryFlux()... // 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: ```js var data = batch |queryFlux()... // 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/reference/nodes/alert_node/) is the last piece it can be further modified as usual. Example: ```js var data = batch |queryFlux()... // 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: ```js var data = batch |queryFlux()... // 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... ``` ```js queryFlux|deadman(threshold float64, interval time.Duration, expr ...ast.LambdaNode) ``` Returns: [AlertNode](/kapacitor/v1/reference/nodes/alert_node/) ### Default Create a node that can set defaults for missing tags or fields. ```js queryFlux|default() ``` Returns: [DefaultNode](/kapacitor/v1/reference/nodes/default_node/) ### Delete Create a node that can delete tags or fields. ```js queryFlux|delete() ``` Returns: [DeleteNode](/kapacitor/v1/reference/nodes/delete_node/) ### Derivative Create a new node that computes the derivative of adjacent points. ```js queryFlux|derivative(field string) ``` Returns: [DerivativeNode](/kapacitor/v1/reference/nodes/derivative_node/) ### Difference Compute the difference between points independent of elapsed time. ```js queryFlux|difference(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Distinct Produce batch of only the distinct points. ```js queryFlux|distinct(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Ec2Autoscale Create a node that can trigger autoscale events for a ec2 autoscalegroup. ```js queryFlux|ec2Autoscale() ``` Returns: [Ec2AutoscaleNode](/kapacitor/v1/reference/nodes/ec2_autoscale_node/) ### Elapsed Compute the elapsed time between points. ```js queryFlux|elapsed(field string, unit time.Duration) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/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. ```js queryFlux|eval(expressions ...ast.LambdaNode) ``` Returns: [EvalNode](/kapacitor/v1/reference/nodes/eval_node/) ### First Select the first point. ```js queryFlux|first(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Flatten Flatten points with similar times into a single point. ```js queryFlux|flatten() ``` Returns: [FlattenNode](/kapacitor/v1/reference/nodes/flatten_node/) ### HoltWinters Compute the Holt-Winters (/influxdb/v1/query\_language/functions/#holt-winters) forecast of a data set. ```js queryFlux|holtWinters(field string, h int64, m int64, interval time.Duration) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### HoltWintersWithFit Compute the Holt-Winters (/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. ```js queryFlux|holtWintersWithFit(field string, h int64, m int64, interval time.Duration) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/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`. ```js queryFlux|httpOut(endpoint string) ``` Returns: [HTTPOutNode](/kapacitor/v1/reference/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. ```js queryFlux|httpPost(url ...string) ``` Returns: [HTTPPostNode](/kapacitor/v1/reference/nodes/http_post_node/) ### InfluxDBOut Create an influxdb output node that will store the incoming data into InfluxDB. ```js queryFlux|influxDBOut() ``` Returns: [InfluxDBOutNode](/kapacitor/v1/reference/nodes/influx_d_b_out_node/) ### Join Join this node with other nodes. The data is joined on timestamp. ```js queryFlux|join(others ...Node) ``` Returns: [JoinNode](/kapacitor/v1/reference/nodes/join_node/) ### K8sAutoscale Create a node that can trigger autoscale events for a kubernetes cluster. ```js queryFlux|k8sAutoscale() ``` Returns: [K8sAutoscaleNode](/kapacitor/v1/reference/nodes/k8s_autoscale_node/) ### KapacitorLoopback Create an kapacitor loopback node that will send data back into Kapacitor as a stream. ```js queryFlux|kapacitorLoopback() ``` Returns: [KapacitorLoopbackNode](/kapacitor/v1/reference/nodes/kapacitor_loopback_node/) ### Last Select the last point. ```js queryFlux|last(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Log Create a node that logs all data it receives. ```js queryFlux|log() ``` Returns: [LogNode](/kapacitor/v1/reference/nodes/log_node/) ### Max Select the maximum point. ```js queryFlux|max(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Mean Compute the mean of the data. ```js queryFlux|mean(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/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 queryFlux|median(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Min Select the minimum point. ```js queryFlux|min(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Mode Compute the mode of the data. ```js queryFlux|mode(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/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 queryFlux|movingAverage(field string, window int64) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/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 queryFlux|percentile(field string, percentile float64) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/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 queryFlux|sample(rate interface{}) ``` Returns: [SampleNode](/kapacitor/v1/reference/nodes/sample_node/) ### Shift Create a new node that shifts the incoming points or batches in time. ```js queryFlux|shift(shift time.Duration) ``` Returns: [ShiftNode](/kapacitor/v1/reference/nodes/shift_node/) ### Sideload Create a node that can load data from external sources. ```js queryFlux|sideload() ``` Returns: [SideloadNode](/kapacitor/v1/reference/nodes/sideload_node/) ### Spread Compute the difference between `min` and `max` points. ```js queryFlux|spread(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### StateCount Create a node that tracks number of consecutive points in a given state. ```js queryFlux|stateCount(expression ast.LambdaNode) ``` Returns: [StateCountNode](/kapacitor/v1/reference/nodes/state_count_node/) ### StateDuration Create a node that tracks duration in a given state. ```js queryFlux|stateDuration(expression ast.LambdaNode) ``` Returns: [StateDurationNode](/kapacitor/v1/reference/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 queryFlux|stats(interval time.Duration) ``` Returns: [StatsNode](/kapacitor/v1/reference/nodes/stats_node/) ### Stddev Compute the standard deviation. ```js queryFlux|stddev(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Sum Compute the sum of all values. ```js queryFlux|sum(field string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### SwarmAutoscale Create a node that can trigger autoscale events for a Docker swarm cluster. ```js queryFlux|swarmAutoscale() ``` Returns: [SwarmAutoscaleNode](/kapacitor/v1/reference/nodes/swarm_autoscale_node/) ### Top Select the top `num` points for `field` and sort by any extra tags or fields. ```js queryFlux|top(num int64, field string, fieldsAndTags ...string) ``` Returns: [InfluxQLNode](/kapacitor/v1/reference/nodes/influx_q_l_node/) ### Trickle Create a new node that converts batch data to stream data. ```js queryFlux|trickle() ``` Returns: [TrickleNode](/kapacitor/v1/reference/nodes/trickle_node/) ### Union Perform the union of this node and all other given nodes. ```js queryFlux|union(node ...Node) ``` Returns: [UnionNode](/kapacitor/v1/reference/nodes/union_node/) ### Where Create a new node that filters the data stream by a given expression. ```js queryFlux|where(expression ast.LambdaNode) ``` Returns: [WhereNode](/kapacitor/v1/reference/nodes/where_node/) ### Window Create a new node that windows the stream by time. NOTE: Window can only be applied to stream edges. ```js queryFlux|window() ``` Returns: [WindowNode](/kapacitor/v1/reference/nodes/window_node/)