art-gelenler-event-driven

Tutorial - Event-Driven Microservices: Spring Boot, Kafka and Elastic - from Ali Gelenler (Udemy)

Section 3: First service: twitter-to-kafka-service - How to use Twitter4j & Kafka producers

13. Running Apache Kafka cluster with docker: Kafka, Zookeeper and Schema Registry

1. Start kafka cluster
   • docker-compose -f common.yml -f kafka_cluster.yml up
2. Kafkacat command line
   • docker run --tty --network host confluentinc/cp-kafkacat kafkacat -b localhost:29092 -L
   • -L - list
   • -b - brokers
   • Kafkacat docker commands

19. Integrate Kafka modules with Microservice: Use Kafka as event store for service

1. Kafkacat as consumer
   • docker run --rm --tty --network host confluentinc/cp-kafkacat kafkacat -b localhost:29092 -C -t twitter-topic
   • docker container ls -a --filter ancestor=confluentinc/cp-kafkacat - list useless containers
   • docker container rm $(docker container ls -a --filter ancestor=confluentinc/cp-kafkacat -q) - remove all containers by image name

Section 4: Externalizing configuration with Spring Cloud Config Server

25. Using remote GitHub repository

1. Create private repository art-gelenler-event-driven-config-repo
2. Create github access token
   • Settings -> Developer settings -> Personal Access Tokens -> Create new
   • Select scopes: repo
   • Generate token
   • Copy token
3. Create environment variable
   • GITHUB_ACCESS_TOKEN = {Paste token here}
4. Use separate-remote-git-repo spring profile to start application

28. Using JCE to encrypt sensitive data

1. Install SDKMAN (I used WSL Ubuntu in Windows)
2. Install Spring Boot
   • sdk install springboot
3. Check installations
   • ls ~/.sdkman/candidates/
   • cd ~/.sdkman/candidates/springboot
4. Install Spring Cloud CLI
   • spring install org.springframework.cloud:spring-cloud-cli:3.1.1
5. Encrypt password
   • spring encrypt PLAIN_TEXT --key KEY
6. Set ENCRYPT_KEY through Environment variable

Section 5: kafka-to-elastic-service: How to use Kafka consumers and Elastic Index API

36. Running elastic search with docker

1. Start elastic cluster
   • docker-compose -f common.yml -f elastic_cluster.yml up
2. In case of error in Windows
   • max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
   • use commands for Windows
   • wsl -d docker-desktop
   • sysctl -w vm.max_map_count=262144
   • or permanently add vm.max_map_count = 262144 to /etc/sysctl.conf

Section 9: Securing the services: Spring security OAuth2, OpenID connect, Keycloak and JWT

68. Run and configure Keycloak authorization server with OIDC for authentication

• Configure Keycloak

Stack variations

ENCRYPT_KEY must be provided through System Environment Variables

1. Infrastructure (without microservices)
   • docker-compose up -d
   • docker-compose --profile=debug up -d (with adminer, kibana)
2. Full stack
   • docker-compose --profile=app up -d