Share Data Across Two Integration Flows with Data Store and Variables in CPI

To share data across multiple integration flows, you can use a global variable.

The following example integration flows use a global variable to share data:

Integration Flow 1 – Write Variable

This integration flow is initiated by a timer. It connects to an external WebShop and reads data from there to store it on the tenant database (as Data Store entry). The data comprises the list of available products at the time when the integration is operated.

This integration flow also stores the actual timestamp as variable.
Integration Flow 2 – Read Variable

This integration flow is also initiated by a timer and runs independently from the first one. It reads the product data (provided by the first integration flow) from the tenant database.

This integration flow also reads the timestamp associated with the latest execution of the first integration flow.

Design Integration Flow 1 – Write Variable

Design integration flow Integration Flow 1 - Write Variable as depicted in the following figure:

The Request Reply step Request product data from WebShop connects through the OData channel to the WebShop component and reads product data for all products in the product catalog.

Configure the OData adapter in the following way:

In the Connection tab, specify the following value for the Address parameter:

https://refapp-espm-ui-cf.cfapps.eu10.hana.ondemand.com/espm-cloud-web/espm.svc/

The external data source supports the Open DataProtocol (OData). For our scenario, we use the ESPM WebShop, which is based on the Enterprise Sales and Procurement Model (ESPM) provided by SAP. The demo application can be accessed at the following address: https://refapp-espm-ui-cf.cfapps.eu10.hana.ondemand.com/webshop/index.html

In tab Processing, specify the following parameters:

Parameter Value

Operation Details Query (GET)

Resource Path Products

Query Options $select=ProductId,Price,CurrencyCode,Name

This OData request reads product details (ProductID, Price, CurrencyCode, and Name) from the WebShop application.
Configure the Write Variables step Store timestamp in the following way.
- In field Name, enter Timestamp.
- For parameter Type, select Expression.
- For parameter Data Type, enter java.lang.String.
- For parameter Value, enter ${date:now:yyyy-MM-dd HH:mm:ss}.
- Select the parameter Global Scope in order to share the variable with other integration flows on the same tenant.
Using this expression, the Write Variables step stores the actual timestamp as global variable.
Configure the Data Store Write step Write product data into data store in the following way.
- For Data Store Name enter ProductCatalog.
- Don’t enter any value for parameter Entry ID.
This step stores the response from the WebShop (which contains the list of all products) as Data Store entry (as entry ID a guid is generated).

You need to deploy this integration first (before deploying the second one).

Parameter	Value
Operation Details	Query (GET)
Resource Path	Products
Query Options	$select=ProductId,Price,CurrencyCode,Name

Design Integration Flow 2 – Read Variable

Design integration flow Integration Flow 2 - Read Variable as depicted in the following figure:

This integration flow is also started by a Timer start event. It reads a product list from the Data Store (that has been updated by the first integration flow) and consumes the timestamp from the first integration flow. It then sends the message content (including the timestamp) to an email receiver.

Configure the Data Store Select step Select from data store in the following way.
- For Data Store Name enter ProductCatalog.
- For parameter Visibility, select Global.
This step reads the entry of the ProductCatalog Data Store that has been created by integration flow Integration Flow 1 – Write Variable. This entry contains the product catalog content read from the WebShop during the recent message processing run of first integration flow Integration Flow 1 – Write Variable.
Configure the Content Modifier Create property for payload and timestamp with the following parameters:

In tab Exchange Property, add the following properties:
- A property containing the payload of the message (which is the content read from the ProductCatalog Data Store entry).
  
  As Type, select Expression, and in field Value enter ${in.body}.
- A property containing the timestamp for the latest message processing run of integration flow Integration Flow 1 – Write Variable. This property is defined by selecting the global variable set by the other integration flow.
  
  As Type, select Global Variable, and in field Value enter Timestamp.
  
  This property is defined based on the global variable written by the first integration flow.
Configure the Content Modifier Define message body so that it defines the message body using the following expression:
```
Prices have been updated at ${property.timestamp};
${property.payload}
```

Configure the Mail receiver adapter so that it sends the message to an email account of your choice.

The received email tells the user the time when the ProductCatalog Data Store entry has been updated the latest and provide the content of the product catalog (XML structure).

In this case, I will take the QQ mail as an example.