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The Future of ServicesJamie Allen
Sr. Director of Global Solutions Architects
@jamie_allen
Traditional application architectures and platforms are obsolete.Gartner
@jamie_allen
• Accelerate teams• Reduce dependency nightmares• Increase application throughput
What are we trying to achieve?
Calvin and Hobbes, Bill Waterston
@jamie_allen
• Size is irrelevant
“Microservices” is a lousy term
Bing Images
@jamie_allen
• At the API• In our source• For our data
We want isolation
Wikipedia, Creative Commons, created by DFoerster
@jamie_allen
We want realistic data management• Use CQRS and Event Sourcing, not CRUD• Transactions, especially distributed, will not work• Consistency is an anti-pattern at scale• Distributed locks and shared data will limit you• Data fabrics break all of these conventions
Think in terms of compensation, not prevention.Kevin Webber, Lightbend
@jamie_allen
We want to ACID v2• Associativity, not Atomicity• Commutativity, not Consistency• Idempotent, not Isolation• Distributed, not Durable
Wikipedia, Creative Commons, created by Weston.pace
@jamie_allen
We want real resilience• It is merely whether or not something has been handled• It is only an external view, not internal where the failure has occurred• Resilience is being able to handle the “why” in a meaningful way
• Threads• Within One Node• Across Many Nodes• Across Many Servers• Across Data Centers
@jamie_allen
We want asynchronous APIs• Synchronous request/response semantics are expensive
• REST can be asynchronous, but still heavy• Each call requires a connection• Best used for external APIs
• Stream-based interactions for inter-service communication where responses are not required
• Message-based interactions for inter-service communication where responses are required
@jamie_allen
We want immutable deployments• We can bind a build of our application to a version of our configuration and
always know what is currently running • You cannot edit configuration and keep running
Dilbert, Scott Adams
@jamie_allen
We want to expose a “tip of the iceberg”
• Users see the public API• The API hides much complexity
MyBluePuzzle.org
@jamie_allen
We want Domain Driven Design• Knowing/understanding it is not necessarily a requirement• “Solving your pain” is the most important reason for microservices• In a greenfield project, Bounded Contexts and Aggregate Roots can help you to
decompose the problem
@jamie_allen
• Proxying• Service Discovery• Stateless aggregation• Orchestration• Failure management• Versioning
We will have additional operational complexity
Complexityandotherbeasts.com
@jamie_allen
• Service API• Persistence API• Development environment• Production environment
@jamie_allen
• IO and communication• Streaming between services as a first-class concept• Higher level of resilience and scalability with no blocking• Service is a Bounded Context in DDD
Lagom Service API
@jamie_allen
• Event sourced (deltas) with Cassandra backend by default• No object/relational impedance mismatch• Can always replay to determine current state• Allows you to learn more from your data later• Persistent entity is an Aggregate Root in DDD• Can be overridden for CRUD if you want
Lagom Persistence API
@jamie_allen
• Create single project definition in sbt, use runAll, includes:• In-memory Cassandra with own keyspaces• A service locator• A service gateway
• Overload Mode: recompile and redeploy on save
Development Environment
@jamie_allen
• Deployment• Monitoring• Scaling• Can test locally with ConductR then push to production• Launch multiple instances with a single command
Production Environment (Lightbend RP)
@jamie_allen
LinksProject Site:http://www.lightbend.com/lagom
GitHub Repo:https://github.com/lagom
Documentation:http://www.lagomframework.com/documentation/1.0.x/Home.html
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