dsyer

Messaging Microservices

Messaging and asynchronous patterns are completely natural with microservices, but a lot of the start of the art material concentrates on HTTP, JSON and REST. This document is about "Message-driven Microservices" with Spring. It tracks the convergence of various ideas that are floating around in Spring Cloud, Spring Boot and Spring XD.

There is already a spring-xd-module-runner project where we started experimenting with allowing user to develop and run an XD module locally. We can extrapolate from there to a more flexible model that leads optionally to a deployable XD module, but can also be used to form more flexible structures than a simple "stream".

Basic Programming Model

Just create MessageChannels "input" and/or "output" and add @EnableMessageBus and run your app as a Spring Boot app (single application context). You need to connect to the physical broker for the bus, which is automatic if the relevant bus imple

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Keybase proof

I hereby claim:

• I am dsyer on github.
• I am dsyer (https://keybase.io/dsyer) on keybase.
• I have a public key whose fingerprint is 032D F42A 76D3 4CD8 DE76 BEFC 257D 4510 E2E1 1827

To claim this, I am signing this object:

dsyer

From WebSecurityConfigurerAdapter.init(WebSecurity):

public void init(final WebSecurity web) throws Exception {
  final HttpSecurity http = getHttp();
  web
    .addSecurityFilterChainBuilder(http)
    .postBuildAction(new Runnable() {
      public void run() {
 FilterSecurityInterceptor securityInterceptor = http.getSharedObject(FilterSecurityInterceptor.class);

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configserver:
  image: dsyer/java
  volumes:
    - ./configserver:/var/run/app
  command: bash -c 'java -jar /var/run/app/target/*.jar'
  links:
    - eureka
  environment:
    - SPRING_PROFILES_ACTIVE=docker
  ports:

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Aggressive Bean Instantiation and "Unproxyable" Beans

This project is a minimal setup depending only on spring-context but mimicking closely the mess that you get into with @EnableTransactionManagement (spring-tx) or @EnableGlobalMethodSecurity (spring-security). These annotations lead to registration of an InfrastructureAdvisorAutoProxyCreator which is responsible for locating the Advisor bean that provides the enabled feature. The mess is caused by aggressive bean instantiation in that component which can cause cascades of unsafe bean instantation

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Notes on Reactive Programming

Reactive Programming is sexy (again) and a lot of people are making a lot of noise about it at the moment, not all of which is very easy to understand for an outsider and lowly enterprise Java developer like me. These notes are what I came up with to help me clarify my understanding of what the noise is about. I have tried to keep them as concrete as possible, and promise not to mention "denotational semantics" because I don't have a higher degree in Computer Science (and if I did it's hard to see how it would help). If you are looking

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Demo for links

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*~
#*
.#*
.gradle
*.sw?
*.class
.classpath
.project
.settings
bin

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*/src/META-INF/
*/src/main/java/META-INF/
samples/*/*/src/main/webapp/META-INF/
target/
.classpath
.project
.DS_Store
.settings/
*.iml
*.iws

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*.gem
.bundle
Gemfile.lock
pkg/*
vendor/
*~
#*
dev.yml