# Workflows with a Dynamic Destination Path
## 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 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*](https://documentation.astera.com/dataflows/transformations/expression-transformation) object in the workflow.
### Parameterizing the Dataflow
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/dataflows/sources/excel-workbook-source). The source data is passed through an [*Aggregate Transformation*](https://documentation.astera.com/dataflows/transformations/aggregate-transformation) and loaded to an [*Excel Workbook Destination*](https://documentation.astera.com/dataflows/destinations/excel-workbook-destination).
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 loaded to a distinctive *Excel Workbook Destination* file.
For this purpose, we will add a *Variables* object and parameterize the source file path and destination file path in the dataflow.
1. Go to *Toolbox > Resources > Variables*, and drag-and drop the *Variables* object onto the dataflow designer.
The *Variables* object is currently empty and needs to be configured.
2. Right-click on the object’s header and select *Properties* from the context menu. A properties window will open.
3. On the *Variable Properties* window, create two new fields:
* *Excel\_Source*
* *Excel\_Destination*
Set both fields as *Input*. For their *Default Value*, paste the path for customer account file source and customer account file destination in each field, respectively.
Click *OK.*
4. Double-click on the *Customer\_Account* source object header. An *Excel Source Properties* window will open. Click *Next,* and the *Layout Builder* will open. Click *Next* again, and the *Config Parameters* screen will open.
5. On the *Config Parameters* window, under the *Value* column for *File Path*, provide the name of the field enclosed in {….} that points to the source file path in the *Variables* object in step 3.
6. Now, Repeat steps 4 and 5 for the *ExcelDestination* object.
Our dataflow has been parameterized. The next step is to create a workflow with a dynamic destination path.
### Creating a Workflow
1. Open a new workflow by going to *File > New > Workflow*.
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*](https://documentation.astera.com/dataflows/sources/file-system-items-source) object onto the workflow designer.
3. Right-click on the object’s header and select *Properties* from the context menu. A configuration window will open for the *FileSystem* object.
4. Provide the local directory path in *File Location*. Apply a *Filter*, \**.xls* and click *OK.*
5. Right-click on the *FileSystem* source object’s header and select *Loop* from the context menu. This will direct Astera to run the task in a loop, replacing the source file paths in real-time, until all source files have been processed.
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 *FileSystem* source object onto the header input port of the *Run Dataflow* object.
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.*
8. Go to *Toolbox > Transformation > Constant Value*, drag-and-drop the [*Constant Value*](https://documentation.astera.com/dataflows/transformations/constant-value-transformation) transformation object onto the workflow designer. Double-click on its header, a *Constant Value Map Properties* window will open.
9. Paste the path of the folder where Astera will load the destination files, in the *Constant Value* box as shown below. Click *OK.*
10. Go to *Toolbox > Transformation > Expression*, drag-and-drop the *Expression* transformation object onto the workflow designer. Double-click on its header, and a *Layout Builder* screen will open.
11. On this *Layout Builder* screen, create four new fields and set the data type accordingly.
* *FullPath*
* *DestinationDirectory*
* *FileName*
* *DestinationFilePath*
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 object 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.
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”
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.
This will create a unique destination file for each source file.
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