# Workflows with a Dynamic Destination Path

Workflows are designed to orchestrate an automated and iterative execution of ordered tasks. When designing a workflow to orchestrate a process, a source object is required, that can provide access to a directory containing a bulk load of source files of the same layout and format. A workflow is designed, such that each source file in that particular directory goes through the same data processing.

This requires a source file to be replaced in the run-time until all source files (of the same layout and format) within a directory are processed and loaded to respective destination files. Now, this further involves the associated destination files to be replaced in the run-time as well, hence making it essential to provide a dynamic destination path. For example, a source directory containing 100 Excel source files in this workflow will create 100 destination files after going through the process.

In this document, we will learn to create workflows with a dynamic destination path that directs Astera to create a unique destination file for each source file.

In Astera, a dynamic destination path is achieved in two steps:

1. Parameterizing the dataflow through a *Variables* object.
2. Providing a run-time destination path through an [*Expression Transformation*](/astera-data-stack-v7/dataflows/transformations/expression-transformation.md) object in the workflow.

## **Creating a Workflow**

In this case, we are orchestrating a simple dataflow that contains customer account details coming in through an [*Excel Workbook Source*](https://documentation.astera.com/v/astera-data-stack-v7/dataflows/sources/excel-workbook-source). The source data is passed through an [*Aggregate Transformation*](https://documentation.astera.com/v/astera-data-stack-v7/dataflows/transformations/aggregate-transformation) and loaded to an[ *Excel Workbook Destination*](https://documentation.astera.com/v/astera-data-stack-v7/dataflows/destinations/excel-workbook-destination).

![](/files/F9gtCjpiUVwbIUlQunsV)

Now, there are 100 Excel source files in a directory containing customer account details of 100 customers. Each of these *Customer\_Accounts* files must go through the same aggregate transformation and be loaded to a distinctive *Excel Workbook Destination* file.

For this purpose, we will create a workflow.

1. Open a new workflow by going to *File > New > Workflow*.

![](/files/uYOOKyyAcsfRXX8vlkkG)

2. To provide access to the local source directory containing 100 customer account files, go to *Toolbox > Sources > File System Item Source* and drag and drop the *File System Item Source* object onto the workflow designer.
3. Right-click on the object’s header and select *Properties* from the context menu. A properties window will open.

![](/files/WZeOb4I2QCWShJoETd6n)

4. Provide the local directory path in *File Location*. Apply a filter .xls and click *OK*.

![](/files/lMfAvZdfI1h4G3k2Qhbb)

5. Right-click on the *File System Item Source* object’s header and select *Loop* from the context menu. This will direct Astera to run the task in a loop until all the source files have been processed through it.

![](/files/cEjM6AtspGQteBtUGao5)

6. Go to *Toolbox > Workflow Tasks > Run Dataflow* and drag and drop the *Run Dataflow* object onto the workflow designer. Map the header output port of the *File System Item Source* onto the header input port of the *Run Dataflow* object.

![](/files/F1zh4JieXAh90unL3BYw)

7. Right-click on the *Run Dataflow* object’s header and select *Properties* from the context menu. Here, provide the *Job Info* path for the dataflow that is being orchestrated and click *OK*.

![](/files/AhDEWukzOK7ktMbRe5mG)

8. Go to *Toolbox > Transformation > Constant Value*, and drag and drop the *Constant Value* transformation object onto the workflow designer. Double-click on its header, a *Constant Value Map Properties* window will open.

![](/files/0teAx6o3kEljTmDDFFXI)

9. Paste the path to the folder where Astera will load the destination files, in the *Constant Value* box as shown below. Click *OK*.\\

![](/files/ENFejnHlkC5GU4puG0Vq)

10. Go to *Toolbox > Transformation > Expression*, and drag and drop the *Expression* transformation object onto the workflow designer. Double-click on its header and a *Layout Builder* screen will open.

![](/files/izg0oD0w9A40HncSikif)

11. On this *Layout Builder* screen, create four new fields and set the data type accordingly.
    * *FullPath*
    * *DestinationDirectory*
    * *FileName*
    * *DestinationFilePath*

![](/files/Rp38EL1UvZjSv9AfvfYx)

Click *OK.*

12. Define field mappings as follows:
    * *FullPath* field under *FileSystem* source object onto the *FullPath* field under *Expression* transformation object.
    * *FullPath* field under *FileSystem* source objects onto the *Excel\_Source* field under *RunDataflow* task object.
    * *Value* field under *Constant Value* transformation object onto the *DestinationDirectory* field under *Expression* transformation object.
    * *DestinationFilePath* field under *Expression* transformation object onto the *Excel\_Destination* field under *RunDataflow* task object.

![](/files/GShpMFv8dkohXwl7dAFD)

13. Double-click on the *Expression* transformation object’s header, to open its *Layout Builder* screen. Write the following expressions for these fields:
    * *FileName*: LSplit(RSplit(FullPath,2,”\”,0),2,”.”,0)
    * *DestinationFilePath*: DestinationDirectory+FileName+”.xls”

![](/files/U7x3SvXBV3NGz5AxW5ht)

Click *OK.* A dynamic destination file path has been created.

14. Click on the *Start Workflow* icon located in the toolbar at the top and execute this workflow.

![](/files/U70QAkdj4oEt1iBdmGOc)

This will create a unique destination file for each source file.


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