Application Server Controlled Resources (ASCR)

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ASCR is applied to Enterprise deployments where interactive clients are connected via Blue Prism application servers. Application Server Controlled Resources (ASCR) streamlines connectivity and increases the number of runtime resources that can be deployed in a single Blue Prism environment. ASCR allow organizations to deploy more than twice the number of digital workers into a single Blue Prism environment compared to Blue Prism version 6.


ASCR is used automatically when the following conditions are met:

  • Blue Prism version 7.0 or later is installed.
  • Interactive clients are connected via Blue Prism application servers.
  • The Blue Prism application server is configured to support callbacks – this configuration is mandatory. See ASCR server configuration for details.

Application server controlled resources

With ASCR, interactive clients communicate with available runtime resources via an application server, meaning that individual connections from each interactive client to each runtime resource no longer need to be made. This increases efficiency and enhances the potential for greater scale. ASCR uses connections on demand, connections are established, used and terminated as needed. Previously, connections were held open permanently.

An event channel (gRpc/WCF bi-directional events in the diagram above) enables the client UI to receive updates from runtime resources in near real time. For example, when a session starts on a runtime resource, a session started event is sent to all connected services. With ASCR, this is only sent to the application servers. The callback channel enables such events to be forwarded to all connected client UIs. This enables the Control Room to update in near real time, without the need for the client UI to be directly connected to each runtime resource in the environment.

Blue Prism application servers and interactive clients must meet the specified minimum requirements, depending on the selected callback protocol, in order to successfully operate ASCR functionality.

Interactive client controlled resources

The following diagram shows the Blue Prism version 6 architecture. All interactive clients have connections to all available resources. This uses system resources both when creating and refreshing the connections; and when utilizing those resources.

This method is still used in Blue Prism version 7 if interactive clients are making a direct database connection.