This is a guest post by Denis Brækhus and Espen Braastad, developers on the Varnish API Engine from Varnish Software. Varnish has long been used in discriminating backends, so it's interesting to see what they are up to.
Varnish Software has just released Varnish API Engine, a high performance HTTP API Gateway which handles authentication, authorization and throttling all built on top of Varnish Cache. The Varnish API Engine can easily extend your current set of APIs with a uniform access control layer that has built in caching abilities for high volume read operations, and it provides real-time metrics.
Varnish API Engine is built using well known components like memcached, SQLite and most importantly Varnish Cache. The management API is written in Python. A core part of the product is written as an application on top of Varnish using VCL (Varnish Configuration Language) and VMODs (Varnish Modules) for extended functionality.
We would like to use this as an opportunity to show how you can create your own flexible yet still high performance applications in VCL with the help of VMODs.