Application Integration Services
Application integration is the process of connecting different applications or application components to allow them to share and exchange data. This helps you build applications that can reuse existing services and systems to do more with less coding. Take a walk through some use cases and use the right tool for each one.
In Figure 9.1, you have one Lambda function directly invoking another Lambda function. This can be problematic. If the second Lambda function has reached its scaling limit at the point it has been invoked, the request will simply be lost. Ideally, you need a buffer to hold requests until the Database Update Lambda function is ready to accept them. This is the purpose of message queues and, on AWS, that service is Amazon SQS. Take a look at Figure 9.2, which explains this:
Figure 9.2: A message queue acts as a middleman, storing messages for consumers
Amazon SQS
Imagine a busy restaurant kitchen...
