"minimal" Message-Driven Microsevervice implementation with Monitoring, Tracing, Circuitbreakers and Sleuth logging meta-data downstream

Synopsis

This project tries to "demo" a message-driven Microservice reference implementation.

MicroserviceApplication can be startet as standalone app acting

• as message source (Profile source) generating messages every x seconds
• as tier1 processor (Profile tier1) consuming messages send by source app and sending to tier2 app
• as tier2 processor (Profile tier2) consuming messages send by tier1 app and sending to sind app
• as message sink (Profile sink) finally consuming the message and ending the (business) message flow

The app uses the following features and frameworks:

• spring-cloud-stream
  Bindings in: com/hoffi/minimal/microservices/microservice/bootconfigs/StreamBindingsConfig.java
  Channel defs: com/hoffi/minimal/microservices/microservice/bops/channels/ package
• Messaging with RabbitMQ and spring-amqp
• spring-cloud-circuitbreakers via resilience4j-circuitbreaker
  including resilience4j-micrometer and resilience4j-prometheus for dashboarding circuitbreaker conditions
• spring-cloud-sleuth and spring-cloud-zipkin
  for Downstream Tracing of Business Processes and logging instrumentation
• Automatic Tracing instrumentation of spring-cloud-stream RabbitBinders with spring-cloud-stream-binder-rabbit

AND(!)

• spring-cloud-contract CDC (Consumer Driven Contracts)

Overview Image:

TL;DR fast start

compiling

The project is a gradle multi-project (defined in settings.gradle).

The service containing the microservice app is under microservice

Versions of dependencies will be read from ./buildSrc/src/main/kotlin/v/dependencies.kt

starting the applications

a bash script for starting (or dryrun output) all 4 Layer Applications) from within ./microservice/
microservice/scripts/run_microservices dry

SERVER_PORT=8080 SPRING_PROFILES_ACTIVE=local,sink \
    build/libs/minimal_microservice-0.1.0.RELEASE.jar \
        --spring.application.name=microservice_sink \
        --app.businessLogic.tier=sink \
        --logging.file=microservice_sink.log
SERVER_PORT=8081 SPRING_PROFILES_ACTIVE=local,tier2 \
    build/libs/minimal_microservice-0.1.0.RELEASE.jar \
        --spring.application.name=microservice_tier2 \
        --app.businessLogic.tier=tier2 \
        --logging.file=microservice_tier2.log
SERVER_PORT=8082 SPRING_PROFILES_ACTIVE=local,tier1 \
    build/libs/minimal_microservice-0.1.0.RELEASE.jar \
        --spring.application.name=microservice_tier1 \
        --app.businessLogic.tier=tier1 \
        --logging.file=microservice_tier1.log
SERVER_PORT=8083 SPRING_PROFILES_ACTIVE=local,source \
    build/libs/minimal_microservice-0.1.0.RELEASE.jar \
        --spring.application.name=microservice_source \
        --app.businessLogic.tier=source \
        --logging.file=microservice_source.log

Prerequisits for a local start

download and start an openzipkin server:

e.g. by

• curl -sSL https://zipkin.io/quickstart.sh | bash -s
• java -jar zipkin.jar

Access the zipkin UI under https://<zipkinServerIP>:9411

download and start a rabbitmq-server:

follow instructions on RabbitMQ Homepage, use a dockerized version or install it via your favorite package manager

download and install a prometheus server for monitoring:

./monitoring/run_prometheus_docker.sh will give you some instructions on how to setup a dockerized prometheues server

Access Prometheus server under http://<prometheusServerIP>:9090/

Access the Grafana dasboard under http://<grafanaIP>:3000

Project Layout

|-- buildfiles
|-- ci                                          (WiP for concourse pipeline build/install/deploy)
|-- docSources                                  (Documentation md sources)
|-- docs                                        (Generated Documentation pdf/html)
|-- gradle                                      (gradle wrapper dir)
|-- microservice (App sub-project)
|   |-- scripts                                 (helper scripts for App start/demo)
|   `-- src
|       |-- main/java/com/hoffi/minimal/microservices/microservice (App src packages)
|       |   |     |-- bootconfighelpers
|       |   |     |-- bootconfigs               (spring @Configuration classes)
|       |   |     |-- bops                      (bops = BusinessOPerationS = Business code)
|       |   |     |   |-- channels              (spring-cloud-stream channel definitions)
|       |   |     |   |-- inbound               (Sink   (receiving msges) implementations)
|       |   |     |   |-- outbound              (Source (sending msges)   implementations)
|       |   |     |   `-- ws                    (REST webservices/controllers)
|       |   |     |-- businesslogic             (where pure business code resides, without all the boiler plate code)
|       |   |     |-- common
|       |   |     |   `-- dto                   (DTO = DataTransferObject = things send over the wire)
|       |   |     |-- helpers
|       |   |     |-- monitoring                (custom monitoring implementations)
|       |   |     |   |-- annotations           (Annotations for Monitoring)
|       |   |     |   `-- aspects               (AOP implementation for the Monitoring Annotations)
|       |   |     `-- tracing
|       |   `-- resources
|       |       |-- application.yml
|       |       `-- bootstrap.yml
|       `-- test/java/com/hoffi/minimal/microservices/microservice (Test src packages)
|           |   |-- annotations                 (Convenience Annotations for Tagging Tests)
|           |   ... 
|           |   |     |-- bops
|           |   |     |   |-- inbound
|           |   |     |   |-- outbound
|           |   |     |   |   |-- ContractTier1Test.java  (<-- spring-cloud-contract stub-runner test)
|           |   |     |   |   |-- Contract....java        (<-- spring-cloud-contract stub-runner test)
|           |   |     |   |   `-- ...                     (non spring-cloud-contract tests)
|           |   |     |   |-- testhelpers
|           |   |     |   `-- ws                          (REST webservices tests (non-CDC))
|           |   |     |-- businesslogic
|           |   |     |-- common
|           |   |     |-- contractbaseclasses             (spring-cloud-contract producer side base class impls)
|           |   |     |-- helpers
|           |   |     `-- misc
|           |   `-- testhelpers
|           `-- resources
|               |-- contracts                             (CDC (groovy) contracts)
|                   |-- inbound
|                   `-- outbound
|-- monitoring                                            (helper scripts for setting up prometheus/grafana via docker)
|   |-- grafana
|   `-- prometheus
`-- scripts
    |-- monitoring -> ../monitoring
    `-- scripts -> ../microservice/scripts

so all the _interesting_ implementation things reside inside subproject-folder ./microservice/

Birds-Eye-View (or: where to find the interesting code bits in the repo)

<tbd>

Implementation Features!!!

spring-cloud-stream messaging between µService Apps

<tbd>

spring-cloud-circuitbreaker and Resilience4j Circuitbreakers

<tbd>

Tracing with spring-cloud-sleuth and spring-cloud-zipkin

<tbd>

Monitoring arbitrary methods via custom Annotations and AOP

<tbd>

spring-cloud-contract Consumer-Driven-Contracts (CDC) Testing

<tbd>

miscellaneous stuff

<tbd>

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