Mohan, I think you can build a REST API on top of app1 directly leveraging on its IQ interface. For some examples code you can refer to https://github.com/confluentinc/kafka-streams-examples/tree/6.0.0-post/src/main/java/io/confluent/examples/streams/interactivequeries
Guozhang On Thu, Oct 1, 2020 at 10:40 AM Parthasarathy, Mohan <mpart...@hpe.com> wrote: > Hi Guozhang, > > The async event trigger process is not running as a kafka streams > application. It offers REST interface where other applications post events > which in turn needs to go through App1's state and send requests to App2 > via Kafka. Here is the diagram: > > KafkaTopics---> App1 ---> App2 > | > V > REST ---->App3 > > REST API to App3 and read the local store of App1 (IQ) and send requests > to App2 (through kafka topic, not shown above). Conceptually it looks same > as your use case. What do people do if a kafka streams application (App1) > has to offer REST interface also ? > > -thanks > Mohan > > On 9/30/20, 5:01 PM, "Guozhang Wang" <wangg...@gmail.com> wrote: > > Hello Mohan, > > If I understand correctly, your async event trigger process runs out > of the > streams application, that reads the state stores of app2 through the > interactive query interface, right? This is actually a pretty common > use > case pattern for IQ :) > > > Guozhang > > On Wed, Sep 30, 2020 at 1:22 PM Parthasarathy, Mohan <mpart...@hpe.com > > > wrote: > > > Hi, > > > > A traditional kafka streams application (App1) reading data from a > kafka > > topic, doing aggregations resulting in some local state. The output > of this > > application is consumed by a different application(App2) for doing a > > different task. Under some conditions, there is an external trigger > (async > > event) which needs to trigger requests for all the keys in the local > store > > to App2. To achieve this, we can read the local stores from all the > > replicas and send the request to App2. > > > > This async event happens less frequently compared to the normal case > that > > leads to the state creation in the first place. Are there any > caveats doing > > it this way ? If not, any other suggestions ? > > > > Thanks > > Mohan > > > > > > -- > -- Guozhang > > > -- -- Guozhang
