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01_​Fault_​Tolerant_​Workflow_​Orchestration

Fault tolerant Workflow orchestration

This example shows how to orchestrate the fault tolerant execution of multiple local KNIME Workflows. All Workflows in the batch are repeatedly executed until they succeed or reach a user-defined maximum number of fails.

Setup Workflow Metadata Loop over all Workflows defined in Metadata from previous section Recursive Loop for multiple Workflow execution on fail dependingon parameter "Max_Iterations". Fault tolerant execution of Multiple WorkflowsThis workflow shows how to execute multiple local KNIME Workflows with fault tolerant error handling.In Order to execute multiple Workflows, KNIME provides the "Execute local workflow" Node. However, sometimes a Workflow can fail, especially if the Workflow depends on theavailibility of some kind of external service or maybe the Workflow to be called is not available during execution. We use the Try and Catch Nodes to process failing Workflows anda Recursive Loop to re-run them until the defined maximum number of executions is reached. In any case, each Workflow will produce a row with information such as number of timesthe workflow was executed and the execution time for reporting as well as the final status and a status message. Input Table with Workflow Orchestration Metadata Inner Loop for multiple Workflow execution on ErrorEnd of Inner LoopAdd helper variable for Rule-based Row Splitter Outer Loop Iterate Workflow Metadata Row as Variablecreate Rows from Iteration VariablesExecutes Workflows based on Metadata InputEnd of outer Loop(Collection of batch execution report data) Table Creator RecursiveLoop Start Recursive Loop End Math Formula(Variable) Table Row ToVariable Loop Start Variable toTable Row Local WorkflowExecution Loop End Setup Workflow Metadata Loop over all Workflows defined in Metadata from previous section Recursive Loop for multiple Workflow execution on fail dependingon parameter "Max_Iterations". Fault tolerant execution of Multiple WorkflowsThis workflow shows how to execute multiple local KNIME Workflows with fault tolerant error handling.In Order to execute multiple Workflows, KNIME provides the "Execute local workflow" Node. However, sometimes a Workflow can fail, especially if the Workflow depends on theavailibility of some kind of external service or maybe the Workflow to be called is not available during execution. We use the Try and Catch Nodes to process failing Workflows anda Recursive Loop to re-run them until the defined maximum number of executions is reached. In any case, each Workflow will produce a row with information such as number of timesthe workflow was executed and the execution time for reporting as well as the final status and a status message. Input Table with Workflow Orchestration Metadata Inner Loop for multiple Workflow execution on ErrorEnd of Inner LoopAdd helper variable for Rule-based Row Splitter Outer Loop Iterate Workflow Metadata Row as Variablecreate Rows from Iteration VariablesExecutes Workflows based on Metadata InputEnd of outer Loop(Collection of batch execution report data) Table Creator RecursiveLoop Start Recursive Loop End Math Formula(Variable) Table Row ToVariable Loop Start Variable toTable Row Local WorkflowExecution Loop End

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