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Flow Control

Rill Flow supports dynamic control of the workflow execution path during its runtime, similar to control statements in programming.

Flow Control Nodes​

Flow control nodes include the following types:

switch​

swicth 节点用于在 DAG 图运行时，在多个后续任务中，根据条件选择执行某些任务，并跳过不符合条件的任务。

workspace: default
dagName: switch
alias: release
type: flow
tasks:
  - name: caseA
    category: pass
  - name: caseB
    category: pass
  - name: caseC
    category: pass
  - name: switchTask
    switches:
      - next: caseA
        condition: $.input.[?(@.input == 0)]
      - next: caseB
        condition: $.input.[?(@.input == 5)]
      - next: caseC
        condition: $.input.[?(@.input == 10)]
    inputMappings:
      - source: $.context.input
        target: $.input.input
    category: switch

foreach​

The foreach node is used to loop into a set of sub-tasks.The foreach node is used for looping through a group of tasks. The tasks field defines a list of tasks to be executed, and the optional synchronization field is used to filter tasks from this list for execution, executing them concurrently according to the maximum concurrency defined in synchronization.

The loop arguments are set via iterationMapping.Loop execution parameters are set via iterationMapping. iterationMapping.collection uses the JsonPath format to define the collection to be iterated over, and item defines the name of the current element in the loop. Through the definition of iterationMapping, the parameter mapping in sub-tasks can access corresponding parameter values. For more information about parameter mapping, see: Parameter Mapping.The value of the parameter in the subtask can be obtained by using the iterationMapping definition.See：[参数映射](04-context-and-mapping.md.

category: foreach
name: A
inputMappings:
  - target: $input.segments
    source: $.context. egments
synchronization:
  conditions:
    - $input[?(@. ignal == true]
  maxConcert: 3
iterationMapping:
    collection: $.input. egments
    item: segmentUrl
outputMappings:
  - target: $.context.gopUrls
    source: $output.sub_context.[*]. opUrl
tasks:
   - category: function
     resourceName: protocol:/content
     pattern: task_async
     name: B1
     next: B2
     inputMappings:
        - target: $. nput.segmentUrl
          source: $.context. egmentUrl
     outputMappings:
        - target: $. ontext.gopPath
          source: $.output. opPath
   - category: function
     resourceName: protocol:/content
     name: B2
     pattern: task_async
     inputMappings:
        - target: $. nput.gopPath
          source: $.context. opPath
     outputMappings:
        - target: $. ontext.gopUrl
          source: $output.gopUrl
next: C

paas​

pass is an empty task.The pass is an empty task. When the pass task is executed, it is immediately set to success.

category: pass
name: A
inputMappings:
  - target: $input.url
    source: $.context. rl
outputMappings:
  - target: $context.segment.text
    source: $.context.text
next: B,C

return​

return is used to determine whether or not to skip the next node.The return node is used to decide whether to skip subsequent nodes. When executing the return task, it checks the conditions based on the context information. If the condition evaluates to true, all subsequent nodes are skipped; otherwise, the execution continues.

category: return
name: A
inputMappings:
   - target: $. nput.url
     source: $.context.url
   - target: $. nput.text
     source: $.context.text
conditions:
  - $.input.[?(@.text == "aaaa" && @.url == "bbb")]
next: B