Flow

Trigger a flow in response to a state change in one or more other flows.

You can trigger a flow as soon as another flow ends. This allows you to add implicit dependencies between multiple flows, which can often be managed by different teams.

A flow trigger must have preconditions which filter on other flow executions. It can also have standard trigger conditions. Neither condition type can use Pebble templating expressions; they must be declaratively defined. Upstream execution outputs will be available in a trigger.outputs variable.

yaml
type: "io.kestra.plugin.core.trigger.Flow"

Trigger the transform flow after the extract flow finishes successfully. The extract flow generates a date output that is passed to the transform flow as an input.

yaml

id: extract
namespace: company.team

tasks: 
  - id: final_date
    type: io.kestra.plugin.core.debug.Return
    format: "{{ execution.startDate | dateAdd(-2, 'DAYS') | date('yyyy-MM-dd') }}"

outputs: 
  - id: date
    type: STRING
    value: "{{ outputs.final_date.value }}"

The transform flow is triggered after the extract flow finishes successfully.

yaml
id: transform
namespace: company.team

inputs:
  - id: date
    type: STRING
    defaults: "2025-01-01"

variables:
  result: |
    Ingestion done in {{ trigger.executionId }}.
    Now transforming data up to {{ inputs.date }}

tasks:
  - id: run_transform
    type: io.kestra.plugin.core.debug.Return
    format: "{{ render(vars.result) }}"

  - id: log
    type: io.kestra.plugin.core.log.Log
    message: "{{ render(vars.result) }}"

triggers:
  - id: run_after_extract
    type: io.kestra.plugin.core.trigger.Flow
    inputs:
      date: "{{ trigger.outputs.date }}"
    preconditions:
      id: flows
      flows:
        - namespace: company.team
          flowId: extract
          states: [SUCCESS]

Trigger the silver_layer flow once the bronze_layer flow finishes successfully by 9 AM.

yaml

id: bronze_layer
namespace: company.team

tasks: 
  - id: raw_data
    type: io.kestra.plugin.core.log.Log
    message: Ingesting raw data

yaml
id: silver_layer
namespace: company.team

tasks:
  - id: transform_data
    type: io.kestra.plugin.core.log.Log
    message: deduplication, cleaning, and minor aggregations

triggers:
  - id: flow_trigger
    type: io.kestra.plugin.core.trigger.Flow
    preconditions:
      id: bronze_layer
      timeWindow:
        type: DAILY_TIME_DEADLINE
        deadline: "09:00:00"
      flows:
        - namespace: company.team
          flowId: bronze_layer
          states: [SUCCESS]

Create a System Flow to send a Slack alert on any failure or warning state within the company namespace. This example uses the Slack webhook secret to notify the #general channel about the failed flow.

yaml
id: alert
namespace: system

tasks:
  - id: send_alert
    type: io.kestra.plugin.notifications.slack.SlackExecution
    url: "{{secret('SLACK_WEBHOOK')}}" # format: https://hooks.slack.com/services/xzy/xyz/xyz
    channel: "#general"
    executionId: "{{trigger.executionId}}"

triggers:
  - id: alert_on_failure
    type: io.kestra.plugin.core.trigger.Flow
    states:
      - FAILED
      - WARNING
    preconditions:
      id: company_namespace
      where:
        - id: company
          filters:
            - field: NAMESPACE
              type: STARTS_WITH
              value: company

List of conditions in order to limit the flow trigger.

Pass upstream flow's outputs to inputs of the current flow.

The inputs allow you to pass data object or a file to the downstream flow as long as those outputs are defined on the flow-level in the upstream flow.

Make sure that the inputs and task outputs defined in this Flow trigger match the outputs of the upstream flow. Otherwise, the downstream flow execution will not to be created. If that happens, go to the Logs tab on the Flow page to understand the error.

Preconditions on upstream flow executions

Express preconditions to be met, on a time window, for the flow trigger to be evaluated.

SubType string

Default

[
  "SUCCESS",
  "WARNING",
  "FAILED",
  "KILLED",
  "CANCELLED",
  "RETRIED",
  "SKIPPED",
  "PAUSED"
]

Possible Values

CREATEDRUNNINGPAUSEDRESTARTEDKILLINGSUCCESSWARNINGFAILEDKILLEDCANCELLEDQUEUEDRETRYINGRETRIEDSKIPPED

List of execution states that will be evaluated by the trigger

By default, only executions in a terminal state or in the PAUSED state will be evaluated. Any ExecutionStatus-type condition will be evaluated after the list of states. Note that a Flow trigger cannot react to the CREATED state because the Flow trigger reacts to state transitions. The CREATED state is the initial state of an execution and does not represent a state transition.

The trigger will be evaluated for each state change of matching executions. If a flow has two Pause tasks, the execution will transition from PAUSED to a RUNNING state twice — one for each Pause task. In this case, a Flow trigger listening to a PAUSED state will be evaluated twice.

SubType string

Possible Values

CREATEDRUNNINGPAUSEDRESTARTEDKILLINGSUCCESSWARNINGFAILEDKILLEDCANCELLEDQUEUEDRETRYINGRETRIEDSKIPPED

List of execution states after which a trigger should be stopped (a.k.a. disabled).

The execution ID that triggered the current flow.

The execution labels that triggered the current flow.

The flow ID whose execution triggered the current flow.

The flow revision that triggered the current flow.

The namespace of the flow that triggered the current flow.

Possible Values

CREATEDRUNNINGPAUSEDRESTARTEDKILLINGSUCCESSWARNINGFAILEDKILLEDCANCELLEDQUEUEDRETRYINGRETRIEDSKIPPED

The execution state.

The extracted outputs from the flow that triggered the current flow.

Format partial-time

SLA daily deadline

Use it only for DAILY_TIME_DEADLINE SLA.

Format partial-time

SLA daily end time

Use it only for DAILY_TIME_WINDOW SLA.

Format partial-time

SLA daily start time

Use it only for DAILY_TIME_WINDOW SLA.

Default DURATION_WINDOW

Possible Values

DAILY_TIME_DEADLINEDAILY_TIME_WINDOWDURATION_WINDOWSLIDING_WINDOW

The type of the SLA

The default SLA is a sliding window (DURATION_WINDOW) with a window of 24 hours.

Format duration

The duration of the window

Use it only for DURATION_WINDOW or SLIDING_WINDOW SLA. See ISO_8601 Durations for more information of available duration value. The start of the window is always based on midnight except if you set windowAdvance parameter. Eg if you have a 10 minutes (PT10M) window, the first window will be 00: 00 to 00: 10 and a new window will be started each 10 minutes

Format duration

The window advance duration

Use it only for DURATION_WINDOW SLA. Allow to specify the start time of the window Eg: you want a window of 6 hours (window=PT6H), by default the check will be done between: 00: 00 and 06: 00, 06: 00 and 12: 00, 12: 00 and 18: 00, and 18: 00 and 00: 00. If you want to check the window between 03: 00 and 09: 00, 09: 00 and 15: 00, 15: 00 and 21: 00, and 21: 00 and 3: 00, you will have to shift the window of 3 hours by settings windowAdvance: PT3H

The flow id.

The namespace of the flow.

The namespace of the flow or the prefix if prefix is true.

Default false

If we must look at the flow namespace by prefix (checked using startWith). The prefix is case sensitive.

The flow id.

The namespace of the flow.

Format time

The time to test must be after this one.

Must be a valid ISO 8601 time with offset.

Format time

The time to test must be before this one.

Must be a valid ISO 8601 time with offset.

Default {{ trigger.date }}

The time to test.

Can be any variable or any valid ISO 8601 time. By default, it will use the trigger date.

SubType

Min items 1

The list of filters.

Min length 1

A unique identifier for the filter.

Default AND

Possible Values

ANDOR

The operand to apply between all filters of the precondition.

List of labels to match in the execution.

Default {{ trigger.date }}

The date to test.

Can be any variable or any valid ISO 8601 datetime. By default, it will use the trigger date.

The namespace of the flow.

The flow id.

A key/value map of labels.

SubType string

Possible Values

CREATEDRUNNINGPAUSEDRESTARTEDKILLINGSUCCESSWARNINGFAILEDKILLEDCANCELLEDQUEUEDRETRYINGRETRIEDSKIPPED

The execution states.

Validation RegExp ^[a-zA-Z0-9][a-zA-Z0-9_-]*

Min length 1

A unique id for the preconditions

SubType

A list of preconditions to met, in the form of upstream flows.

Default true

Whether to reset the evaluation results of preconditions after a first successful evaluation within the given time window.

By default, after a successful evaluation of the set of preconditions, the evaluation result is reset. This means the same set of conditions needs to be successfully evaluated again within the same time window to trigger a new execution. In this setup, to create multiple executions, the same set of conditions must be evaluated to true multiple times within the defined window. You can disable this by setting this property to false, so that within the same window, each time one of the conditions is satisfied again after a successful evaluation, it will trigger a new execution.

Default

{
  "type": "DURATION_WINDOW"
}

Define the time window for evaluating preconditions.

You can set the type of timeWindow to one of the following values:

DURATION_WINDOW: this is the default type. It uses a start time (windowAdvance) and end time (window) that advance to the next interval whenever the evaluation time reaches the end time, based on the defined duration window. For example, with a 1-day window (the default option: window: PT1D), the preconditions are evaluated during a 24-hour period starting at midnight (i.e., at "00: 00: 00+00: 00") each day. If you set windowAdvance: PT6H, the window will start at 6 AM each day. If you set windowAdvance: PT6H and also override the window property to PT6H, the window will start at 6 AM and last for 6 hours. In this configuration, the preconditions will be evaluated during the following intervals: 06: 00 to 12: 00, 12: 00 to 18: 00, 18: 00 to 00: 00, and 00: 00 to 06: 00.
SLIDING_WINDOW: this option evaluates preconditions over a fixed time window but always goes backward from the current time. For example, a sliding window of 1 hour (window: PT1H) evaluates executions within the past hour (from one hour ago up to now). It uses a default window of 1 day.
DAILY_TIME_DEADLINE: this option declares that preconditions should be met "before a specific time in a day." Using the string property deadline, you can configure a daily cutoff for evaluating preconditions. For example, deadline: "09: 00: 00" specifies that preconditions must be met from midnight until 9 AM UTC time each day; otherwise, the flow will not be triggered.
DAILY_TIME_WINDOW: this option declares that preconditions should be met "within a specific time range in a day". For example, a window from startTime: "06: 00: 00" to endTime: "09: 00: 00" evaluates executions within that interval each day. This option is particularly useful for defining freshness conditions declaratively when building data pipelines that span multiple teams and namespaces. Normally, a failure in any task in your flow will block the entire pipeline, but with this decoupled flow trigger alternative, you can proceed as soon as the data is successfully refreshed within the specified time window.

SubType

A list of preconditions to met, in the form of execution filters.

Min items 1

The list of conditions to validate.

If any condition is true, it will allow the event's execution.

String against which to match the execution namespace depending on the provided comparison.

Possible Values

EQUALSPREFIXSUFFIX

Comparison to use when checking if namespace matches. If not provided, it will use EQUALS by default.

Default false

Whether to look at the flow namespace by prefix. Shortcut for comparison: PREFIX.

Only used when comparison is not set

SubType

The list of preconditions to wait for

The key must be unique for a trigger because it will be used to store the previous evaluation result.

Validation RegExp ^[a-zA-Z0-9][a-zA-Z0-9_-]*

Min length 1

A unique id for the condition

Default true

Whether to reset the evaluation results of SLA conditions after a first successful evaluation within the given time period.

By default, after a successful evaluation of the set of SLA conditions, the evaluation result is reset, so, the same set of conditions needs to be successfully evaluated again in the same time period to trigger a new execution. This means that to create multiple executions, the same set of conditions needs to be evaluated to true multiple times. You can disable this by setting this property to false so that, within the same period, each time one of the conditions is satisfied again after a successful evaluation, it will trigger a new execution.

Default

{
  "type": "DURATION_WINDOW"
}

Define the time period (or window) for evaluating preconditions.

You can set the type of sla to one of the following values:

DURATION_WINDOW: this is the default type. It uses a start time (windowAdvance) and end time (window) that are moving forward to the next interval whenever the evaluation time reaches the end time, based on the defined duration window. For example, with a 1-day window (the default option: window: PT1D), the SLA conditions are always evaluated during 24h starting at midnight (i.e. at time 00: 00: 00) each day. If you set windowAdvance: PT6H, the window will start at 6 AM each day. If you set windowAdvance: PT6H and you also override the window property to PT6H, the window will start at 6 AM and last for 6 hours — as a result, Kestra will check the SLA conditions during the following time periods: 06: 00 to 12: 00, 12: 00 to 18: 00, 18: 00 to 00: 00, and 00: 00 to 06: 00, and so on.
SLIDING_WINDOW: this option also evaluates SLA conditions over a fixed time window, but it always goes backward from the current time. For example, a sliding window of 1 hour (window: PT1H) will evaluate executions for the past hour (so between now and one hour before now). It uses a default window of 1 day.
DAILY_TIME_DEADLINE: this option declares that some SLA conditions should be met "before a specific time in a day". With the string property deadline, you can configure a daily cutoff for checking conditions. For example, deadline: "09: 00: 00" means that the defined SLA conditions should be met from midnight until 9 AM each day; otherwise, the flow will not be triggered.
DAILY_TIME_WINDOW: this option declares that some SLA conditions should be met "within a given time range in a day". For example, a window from startTime: "06: 00: 00" to endTime: "09: 00: 00" evaluates executions within that interval each day. This option is particularly useful for declarative definition of freshness conditions when building data pipelines. For example, if you only need one successful execution within a given time range to guarantee that some data has been successfully refreshed in order for you to proceed with the next steps of your pipeline, this option can be more useful than a strict DAG-based approach. Usually, each failure in your flow would block the entire pipeline, whereas with this option, you can proceed with the next steps of the pipeline as soon as the data is successfully refreshed at least once within the given time range.

Format duration

The duration of the window

Deprecated, use timeWindow.window instead.

Format duration

The window advance duration

Deprecated, use timeWindow.windowAdvance instead.

Min items 1

The list of conditions to exclude.

If any conditions is true, it will prevent the event's execution.

Possible Values

FIRSTLASTSECONDTHIRDFOURTH

Are you looking for the first or the last day in the month?

Possible Values

MONDAYTUESDAYWEDNESDAYTHURSDAYFRIDAYSATURDAYSUNDAY

The day of week.

Default {{ trigger.date }}

The date to test.

Can be any variable or any valid ISO 8601 datetime. By default, it will use the trigger date.

Possible Values

MONDAYTUESDAYWEDNESDAYTHURSDAYFRIDAYSATURDAYSUNDAY

The day of week.

Default {{ trigger.date }}

The date to test.

Can be any variable or any valid ISO 8601 datetime. By default, it will use the trigger date.

SubType string

Possible Values

CREATEDRUNNINGPAUSEDRESTARTEDKILLINGSUCCESSWARNINGFAILEDKILLEDCANCELLEDQUEUEDRETRYINGRETRIEDSKIPPED

List of states that are authorized.

SubType string

Possible Values

CREATEDRUNNINGPAUSEDRESTARTEDKILLINGSUCCESSWARNINGFAILEDKILLEDCANCELLEDQUEUEDRETRYINGRETRIEDSKIPPED

List of states that aren't authorized.

Format date-time

The date to test must be after this one.

Must be a valid ISO 8601 datetime with the zone identifier (use 'Z' for the default zone identifier).

Format date-time

The date to test must be before this one.

Must be a valid ISO 8601 datetime with the zone identifier (use 'Z' for the default zone identifier).

Default {{ trigger.date }}

The date to test.

Can be any variable or any valid ISO 8601 datetime. By default, it will use the trigger date.

Possible Values

FLOW_IDNAMESPACESTATEEXPRESSION

The field which will be filtered.

Possible Values

EQUAL_TONOT_EQUAL_TOINNOT_INIS_TRUEIS_FALSEIS_NULLIS_NOT_NULLSTARTS_WITHENDS_WITHREGEXCONTAINS

The type of filter.

Can be set to one of the following: EQUAL_TO, NOT_EQUAL_TO, IS_NULL, IS_NOT_NULL, IS_TRUE, IS_FALSE, STARTS_WITH, ENDS_WITH, REGEX, CONTAINS. Depending on the type, you will need to also set the value or values property.

The single value to filter the field on.

Must be set according to its type.

SubType string

The list of values to filter the field on.

Must be set for the following types: IN, NOT_IN.

SubType string

Possible Values

CREATEDRUNNINGPAUSEDRESTARTEDKILLINGSUCCESSWARNINGFAILEDKILLEDCANCELLEDQUEUEDRETRYINGRETRIEDSKIPPED

List of states that are authorized.

SubType string

Possible Values

CREATEDRUNNINGPAUSEDRESTARTEDKILLINGSUCCESSWARNINGFAILEDKILLEDCANCELLEDQUEUEDRETRYINGRETRIEDSKIPPED

List of states that aren't authorized.

ISO 3166-1 alpha-2 country code. If not set, it uses the country code from the default locale.

It uses the Jollyday library for public holiday calendar that supports more than 70 countries.

Default {{ trigger.date }}

The date to test.

Can be any variable or any valid ISO 8601 datetime. By default, it will use the trigger date.

ISO 3166-2 country subdivision (e.g., provinces and states) code.

It uses the Jollyday library for public holiday calendar that supports more than 70 countries.

​Flow

Flow