simulating apis for effective testing: (micro)service virtualisation for the 21st century

@mogronalol

Simulating APIs for Effective Testing: (Micro)Service Virtualisation

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Andrew Morgan @mogronalol

OpenCredo & Spectolabs

@mogronalol 2

About Me

• Consultant at OpenCredo • Background mainly with

Java and now Go • Spectolabs

Andrew Morgan @mogronalol

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Agenda

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Agenda

• The problems with operating and testing distributed systems and microservices

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Agenda


• Overview of Service Virtualisation / Api Simulation

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Agenda


• Overview of Service Virtualisation / Api Simulation• Improving our Tests

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Agenda


• Overview of Service Virtualisation / Api Simulation• Improving our Tests• Data Synchronisation

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Agenda


• Overview of Service Virtualisation / Api Simulation• Improving our Tests• Data Synchronisation• Summary

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Agenda


• Overview of Service Virtualisation / Api Simulation • Improving our Tests • Data Synchronisation • Summary

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-INFOX

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Distributed Systems

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Microservices

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Payment

Company

Booking

Flights

Auth

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A natural evolution...

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Challenges…

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Airline Booking Application

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• Microservice architecture

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• Microservice architecture• Integration with third party services

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• Microservice architecture• Integration with third party services• Integration with legacy internal services

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• Microservice architecture• Integration with third party services• Integration with legacy internal services• Heavy resource consumption

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• Microservice architecture• Integration with third party services• Integration with legacy internal services• Heavy resource consumption• A standard CI/CD pipeline

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Resources

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Resources

Booking

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Resources

Booking

Flights

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Resources

Booking

Flights

Rewards

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Resources

Booking

Flights

Rewards

Payments

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Resources

Booking

Flights

Rewards

Payments

Fraud

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Resources

Booking

Flights

Rewards

Payments

Fraud

Cost

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Licensing

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Licensing

Consumer

Producer

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Licensing

Consumer

Producer

Third party

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Licensing

Consumer

Producer

Consumer

Producer

Third party

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Licensing

Consumer

Producer

Consumer

Producer

Third party Cost

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Dependency Constraints

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Consumer

Producer

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Consumer

Producer

Consumer

Producer

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Flakey Dependencies

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Flakey Dependencies

Consumer

Producer

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Flakey Dependencies

Consumer

Producer

Consumer

Producer

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Doesn't exist

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Doesn't exist

Consumer

?

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Non Deterministic

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Non Deterministic

Consumer

Booking Service

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Non Deterministic

Consumer

Booking Service {

“date” : “2013-01-08”, … }

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Non Deterministic

assertThat(booking.getDate()) .isEqualTo(LocalDate.of(2013,1,8));

Consumer

Booking Service {

“date” : “2013-01-08”, … }

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Non Deterministic

assertThat(booking.getDate()) .isEqualTo(LocalDate.of(2013,1,8));

Consumer

Booking Service {

“date” : “2016-02-07”, … }

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Fault Injection

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Fault Injection

Consumer

Producer

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Fault Injection

Consumer

Producer

Consumer

Producer

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Fault Injection

Consumer

Producer

Consumer

Producer

4xx, 5xx, timeouts

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Fault Injection

Consumer

Producer

Consumer

Producer

4xx, 5xx, timeouts

Operationally challenging to trigger

faults

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Agenda



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Service Virtualisation

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• Emulation of real service

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• Emulation of real service• Non-intrusive

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• Emulation of real service• Non-intrusive• Lightweight - or should be

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Consumer

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Consumer Producer

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Consumer Virtual Producer

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Creating Data

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Creating Data

Consumer

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Creating Data

Consumer Producer

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Creating Data

Consumer ProducerService

Virtualisation Tool

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Creating Data

https://github.com/tomakehurst/wiremock

https://github.com/tomakehurst/wiremock

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Proxy Mode

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Proxy Mode

Consumer

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Proxy Mode

Consumer Producer

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Proxy Mode

Consumer ProducerService

Virtualisation Tool

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Webserver / Facade Mode

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Consumer

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Consumer Producer

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Consumer Producer


Tool

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Not Mocking

Service Under Test

Dependant Service

Http

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Not Mocking

Service Under Test

Mocking

Dependant Service

Http

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Not Mocking

Service Under Test

Mocking

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Not Mocking

Service Under Test

Virtual Service

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Not Mocking

Service Under Test

Virtual Service

Mocks bleed into the architectural boundary of your

application

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Open Source Tooling

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Agenda



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Record and replay

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Record and replay

Consumer

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Record and replay

Consumer External Producer

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Record and replay


Service Virtualisati

on Tool

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JUnit Example

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JUnit Example

@Testpublic void shouldBeAbleToRetrieveABooking() throws URISyntaxException { // Given final int bookingId = 1; // When final Booking booking = bookingServiceGateway.getBooking(bookingId); // Then assertThat(booking.getCustomer()).isEqualTo(“Andrew Morgan”); assertThat(booking.getDate()).isEqualTo(LocalDate.of(2016,3,1));}

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JUnit Example

@Rule public HoverflyRule hoverflyRule = HoverflyRule.inCaptureMode(“src/test/resources/external.json").build();


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JUnit Example{ "data": [ { "request": { "path": "/api/bookings/1", "method": "GET", "destination": "www.my-test.com", "query": null, "body": "" }, "response": { "status": 200, "body": “{\”customer\”:\”Andrew Morgan\", \”date\”: \”2016-03-01\”}}}”, "headers": { "Content-Type": [ "application/json" ] } } } ]}

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JUnit Example


@Rule public HoverflyRule hoverflyRule = HoverflyRule.buildFromClassPathResource(“external.json").build();

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Advantages

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Advantages

• Isolation

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Advantages

• Isolation• Flaky dependencies

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Advantages

• Isolation• Flaky dependencies• Rate limiting

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Advantages

• Isolation• Flaky dependencies• Rate limiting• Deterministic

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Advantages

• Isolation• Flaky dependencies• Rate limiting• Deterministic• Licensing

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Deployment and Infrastructure

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Internal Producer

Internal Producer

Internal Producer

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Consumer

Virtual Service

Virtual Service

Virtual Service

Virtual Service

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CLI Example

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CLI Example

$ hoverctl start —proxy-port 8080

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CLI Example

$ hoverctl start —proxy-port 8080$ hoverctl import accounts-service-simulation.json

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CLI Example


$ hoverctl start —proxy-port 8081

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CLI Example


$ hoverctl start —proxy-port 8081$ hoverctl import payments-service-simulation.json

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CLI Example



$ curl http://www.account-service.com/api/v1/accounts/1 —proxy http://localhost:8080

[{"name":"foo"}]

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CLI Example



$ curl http://www.account-service.com/api/v1/accounts/1 —proxy http://localhost:8080

[{"name":"foo"}]

$ curl http://www.payment-service.com/api/v1/payments/1 -proxy http://localhost:8081

[{“amount":"£23.27"}]

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Fault Injection

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Fault Injection



Tool

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Fault Injection



Tool

Middleware

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Fault Injection

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Advantages

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Advantages

• Transparent

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Advantages

• Transparent• Configurable

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Advantages

• Transparent• Configurable• Operationally simple

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Documentation-Driven

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Consumer ?

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Consumer

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Consumer

Transform

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Virtual Service

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Consumer

Transform

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Advantages

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Advantages

• Documentation Driven Development

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Advantages

• Documentation Driven Development• Work in Parallel

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Agenda



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Data Synchronisation Issues

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Consumer Virtual Service

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ConsumerConsumer Virtual Service

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ConsumerConsumerConsumer Real Service

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Ownership

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Ownership

Own Consumer Own Producer Strategy

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Ownership


Integration Contract Testing

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http://martinfowler.com/bliki/IntegrationContractTest.html


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Scheduled Build



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Scheduled Build

Reproduce Simulations



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Scheduled Build

Reproduce Simulations Diff



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Scheduled Build


Integration Testing or

Contract Diff



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Scheduled Build


No diff?


Contract Diff



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Scheduled Build


No diff?

Diff?


Contract Diff



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Ownership



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Ownership



Virtual Service as First Class Citizen

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Run and Capture

Service Tests

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Run and Capture

Service Tests

Transform to simulation

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Run and Capture

Service Tests


Publish Virtual Service

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Run and Capture

Service Tests

Parse Contract



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Run and Capture

Service Tests

Parse Contract


Parse Documentati

on


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Ownership




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Ownership



Consumer Driven Contract Testing


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http://www.martinfowler.com/articles/consumerDrivenContracts.html


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Consumer Defines Contract



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Generate Producer

Stubs


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Generate Producer

Stubs

Implement Consumer


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Generate Producer

Stubs

Generate Producer Contract

Tests

Implement Consumer


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Implement Producer


Generate Producer

Stubs


Tests

Implement Consumer


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Implement Producer


Generate Producer

Stubs


Tests

Implement Consumer

Run Consumer Contract

Tests


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Change producer



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Change producer


Run Consumer Contract

Tests


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Tools

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Testing Pyramid

End to end

Integration / Service Testing

Unit Testing

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Summary

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Summary

• Cost reduction from simulated services

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Summary

• Cost reduction from simulated services• Easy deployment of simulations

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Summary

• Cost reduction from simulated services• Easy deployment of simulations• Less dependant on end to end testing

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Summary

• Cost reduction from simulated services• Easy deployment of simulations• Less dependant on end to end testing• Better feedback cycle

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Questions?

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@mogronalol

https://github.com/mogronalol

https://github.com/mogronalol

simulating apis for effective testing: (micro)service virtualisation for the 21st century

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