1. Developing for Oracle Application Container Cloud Service
  2. Creating Your Application
  3. Service to Service Communication

Service to Service Communication

Service to service communication is crucial when you build microservices. A microservice-based application typically runs on a single process, and they can interact with each other using a communication protocol, for example, HTTP or TCP. Oracle Application Container Cloud Service allows you to interconnect your applications using different methods depending on the type of application.

Oracle Application Container Cloud Service supports two types of applications:

Web Applications

A web application is a public application that you can access with a public URL. By default, all applications on Oracle Application Container Cloud Service are web applications.

Web applications can be invoked from another web or worker application by using one of the two options:

  • Using the public URL. For example, a REST API exposed by application 'appB' can be invoked by another service 'appA' by making use of the public URL.

  • Using the internal overlay network. Applications can communicate with each other over a secure internal network if all of the applications are marked asisClustered . The application name is used as the host name:

    • If the application binds to the \PORT environment variable., then it can be accessed on port 8080 over HTTP. The URL format is http://<application_name>:8080.

    • If an application binds to a custom port (for example, 9090) in addition to the PORT environment variable and a different protocol, then it can be accessed by using that port and protocol over which it has exposed its service (for example, TCP or HTTP). The URL format is http://<application_name>:<custom_port>.

Worker Applications

A worker application is a private application that doesn’t have a public URL.

Worker applications can only be invoked from another web or worker application by using an internal overlay network. They can talk to each other over a secure internal network if all of them are marked as isClustered.

To invoke a worker application, the application name is used as the host name and it can be accessed by using the port and the protocol where the service is exposed. For example, a REST API over 8082 or a TCP service over 9090. The URL format is http://<application_name>:<port>. 

Communication Patterns

A combination of the different application types and clustering capability leads to following access communication patterns:

Access Pattern Description Public Network Access (Internet) Internal (overlay) Network Access (Clustered)
web-web A web application that invokes another web application. Yes Yes
web-worker A web application that invokes a worker application. No Yes
worker-web A worker application that invokes a web application. Yes Yes
worker-worker A worker application that invokes another worker application No Yes

img/obecloud.pngTutorial - Invoke a worker application from a web application

For more information, see Design Considerations and Clustered Applications.