xoac / signer-flow

An example signer apps that works together through confluence platform

Sign flow

Small project to build sign system with Rust and confluence platform

Architecture

1. each signer-rest-api pod will send MsgToSign to single topic signer.v1
2. each signer-rest-api pod will have separate response topic signer.v1.resp<N> and each instance will be the only group.id member
3. each signer-service will be produce response to resp_topic topic that is know from request header
4. number of signer-service should be less or equal to signer.v1 topic partitions to benefit from horizontal scaling

Run with minikube

Running

1. Run confluence platform for this example I used quickstart-deploy example as base. Here are commands that allowed me to run this on Linux machine. (This may require installion of additional software).

   Prepare (in signer-flow working dictionary)

   minikube start --driver=kvm2 --memory 6144 --cpus 6
   # here you need to wait a few secs
   kubectl create namespace confluent
   kubectl config set-context --current --namespace=confluent
   helm repo add confluentinc https://packages.confluent.io/helm
   helm upgrade --install operator confluentinc/confluent-for-kubernetes

2. Run confluent platform:

   kubectl apply -f k8s/confluent-platform-singlenode.yaml

3. Run signer flow:

   kubectl apply -f k8s/singer-flow.yaml

Access to application

The value returned by commands below will probably be different in your case

1. Get current node ip:

   minikube ip

   In my case it was 192.168.39.211

2. Find singer-rest-api port:

   kubectl get services signer-rest-api

   The port will be generated so output will be different. In my case the port is 32718

   NAME              TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
   signer-rest-api   NodePort   10.105.210.60   <none>        80:32718/TCP   36m
   

3. Get access in browser: http://192.168.39.211:32718/sign

   • to test - input some text to sign and press submit button. The app use base64 encoder to sign messages.
   • the output will returned with ok: <signed_msg> or err: <err> if error occurs

Monitoring

1. Monitor k8s local cluster minikube dashboard --url
2. Monitor confluent platform

   kubectl port-forward controlcenter-0 9021:9021

   now open control center website: http://localhost:9021

Further improvements

Since this is a demo application here is a summary of improvements that could be added

1. The biggest demo problem is with ./k8s/singer-flow.yaml and running singer-rest-api instances. There are 2 possible improvements to current boilerplate solution:
   1. Use helm and template engine to generate instances in loop
   2. Each signer-rest-api instance could create unique topic with prefix signer.v1.resp at startup (I would choose this as an improvment)
2. Add system testing
3. Dockerfiles files are nearly the same and could be unified in one Dockerfile with build arguments.
4. Rust: 0. Application run with tokio tasks if for example one such task panics other tasks can still be running. Application can stop working correctly but still be running.
   1. I use a lot of expect() and unwrap() also for external input
   2. Some code could be shared between signer-service and signer-rest-api
   3. Error handling could be much improved (for example do not pass all KafkaError to end user)
5. Topic schemas could be added
6. browser js client could use json and distinguish error from correct responses
7. Add CD to publish new releases to docker hub

License

Licensed under Boost Software License - Version 1.0 BSL-1.0 or https://www.boost.org/LICENSE_1_0.txt

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the BSL-1.0 license, should not contains any additional terms or conditions.

See CONTRIBUTING.md.