Microservice Resiliency From Front to Back End QCon So Paulo, 2017 - - PowerPoint PPT Presentation

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Microservice Resiliency From Front to Back End QCon So Paulo, 2017 - - PowerPoint PPT Presentation

Aug 06, 2023 283 likes •961 views

Microservice Resiliency From Front to Back End QCon So Paulo, 2017 Lance Ball, Senior Software Engineer, Red Hat Who am I? Senior Software Engineer, Red Hat Who am I? Senior Software Engineer, Red Hat Who am I? Senior Software Engineer,

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Microservice Resiliency

From Front to Back End

QCon São Paulo, 2017

Lance Ball, Senior Software Engineer, Red Hat

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Who am I?

Senior Software Engineer, Red Hat

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Who am I?

Senior Software Engineer, Red Hat

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Who am I?

Senior Software Engineer, Red Hat

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Who am I?

Senior Software Engineer, Red Hat

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µ Service

“

software applications as suites of

independently deployable services

https://martinfowler.com/articles/microservices.html

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µ Service

“

software applications as suites of

independently deployable services

https://martinfowler.com/articles/microservices.html

But what does this mean?!

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What's in an application?

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Stuff

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Monolithic application

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Scaling a monolith

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Microservice application

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Scaled microservices

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Wait... isn't this the UX track?

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Service Lifecycle

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Service Lifecycle

Client makes a request

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Service Lifecycle

Client makes a request Server provides a response

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Service Lifecycle

Client makes a request Server provides a response Often using HTTP transport

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Service Lifecycle

Client makes a request Server provides a response Often using HTTP transport Often with JSON data format

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In the Browser

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In the Browser

XMLHttpRequest

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In the Browser

XMLHttpRequest JQuery

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In the Browser

XMLHttpRequest JQuery AJAX

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Microservice Requests

(simplified)

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Operational Complexity

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Microservices Visualized

https://twitter.com/ThePracticalDev/status/845285541528719360

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Problems

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Problems

Timeouts

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Problems

Timeouts Network saturation

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Problems

Timeouts Network saturation Programmer error

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Problems

Timeouts Network saturation Programmer error Disk failure

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Problems

Timeouts Network saturation Programmer error Disk failure Transitive dependencies

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Cascading failures

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How to deal with all this

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How to deal with all this

Limit single points of failure

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How to deal with all this

Limit single points of failure Shed load when possible

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How to deal with all this

Limit single points of failure Shed load when possible Provide fallback behavior

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How to deal with all this

Limit single points of failure Shed load when possible Provide fallback behavior Optimize failure discovery

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Circuit Breaker

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Circuit Breaker

Calls that could fail are wrapped

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Circuit Breaker

Calls that could fail are wrapped Circuit opens at a failure threshold

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Circuit Breaker

Calls that could fail are wrapped Circuit opens at a failure threshold Further calls short circuit for a while

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Circuit Breaker

Calls that could fail are wrapped Circuit opens at a failure threshold Further calls short circuit for a while Later, circuit tries again and trips immediately if there is failure

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Circuit State

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Async operation that could fail

// Use JQuery to get cart info $.get('http://mystore.com/cart') .then((json) => { // update the UI with JSON data }) .catch((e) => { // oops something went wrong console.error(e); })

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Async operation that could fail

// Use JQuery to get cart info $.get('http://mystore.com/cart') .then((json) => { // update the UI with JSON data }) .catch((e) => { // oops something went wrong console.error(e); })

Shed load when possible

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Aside - Promsies

// Use JQuery to get cart info $.get('http://mystore.com/cart') .then((json) => { // update the UI with JSON data }) .catch((e) => { // oops something went wrong console.error(e); })

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Circuit Breaker Example

// Use JQuery's ajax wrapper and circuit breaker // defaults for failure threshold, timing, etc. const circuit = circuitBreaker($.get); circuit.fire('http://nodejs.org/dist/index.json') .then((json) => { // update the UI with JSON data }) // on failure, just log to console .catch(console.error);

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Circuit Breaker Example

// Use JQuery's ajax wrapper and circuit breaker // defaults for failure threshold, timing, etc. const circuit = circuitBreaker($.get); circuit.fire('http://nodejs.org/dist/index.json') .then((json) => { // update the UI with JSON data }) // on failure, just log to console .catch(console.error);

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Circuit Breaker Example

// Use JQuery's ajax wrapper and circuit breaker // defaults for failure threshold, timing, etc. const circuit = circuitBreaker($.get); circuit.fire('http://nodejs.org/dist/index.json') .then((json) => { // update the UI with JSON data }) // on failure, just log to console .catch(console.error);

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Promises vs. Callbacks

// Wrap Node.js' fs.readFile as a promise-returning function const readFile = circuitBreaker.promisify(fs.readFile); const circuit = circuitBreaker(readFile, options); circuit.fire('./package.json', 'utf-8') .then(console.log) .catch(console.error);

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Circuit Breaker Fallback

Provides default behavior in case of error

circuit.fallback((file) => `Sorry, I can't read ${file}`); // Fallback function is still a success case circuit.fire('./package.jsob') .then((data) => console.log(`package.json: \n${data}`)) .catch((err) => console.error(`ERR: ${err}`));

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Circuit Breaker Fallback

Provides default behavior in case of error

circuit.fallback((file) => `Sorry, I can't read ${file}`); // Fallback function is still a success case circuit.fire('./package.jsob') .then((data) => console.log(`package.json: \n${data}`)) .catch((err) => console.error(`ERR: ${err}`));

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Caching

Always returns the same value

const now = circuitBreaker(Date, { cache: true });

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Caching

Always returns the same value

const now = circuitBreaker(Date, { cache: true }); circuit.fire().then(console.log); // Mon Apr 10 2017 12:10:26 GMT-0400 (EDT) circuit.fire().then(console.log); // Mon Apr 10 2017 12:10:26 GMT-0400 (EDT) circuit.fire().then(console.log); // Mon Apr 10 2017 12:10:26 GMT-0400 (EDT)

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When is this useful?

Frequent hits, infrequent change E.g. username

const username = circuitBreaker(fetchUsername, { cache: true }); // periodically clear the cache setInterval(_ => username.clearCache(), 5000);

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Events

Circuit breakers are event emitters

// Update the UI specifically for timeout errors circuit.on('timeout', () => $(element).prepend( mkNode(`${route} is taking too long to respond.`)));

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`fire` `reject` `timeout` `success` `failure` `open` `close` `halfOpen` `fallback` `snapshot`

Events

Circuit breakers are event emitters

// Update the UI specifically for timeout errors circuit.on('timeout', () => $(element).prepend( mkNode(`${route} is taking too long to respond.`)));

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Status

// create a 10 sec window with 10 buckets of 1 sec const circuit = circuitBreaker(asyncFunc, { rollingCountTimeout: 10000, rollingCountBuckets: 10 }); // status is calculated every time status is accessed const status = circuit.status // print the entire statistical window console.log(status.window); // print the rolling stats console.log(status.stats);

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Status

// create a 10 sec window with 10 buckets of 1 sec const circuit = circuitBreaker(asyncFunc, { rollingCountTimeout: 10000, rollingCountBuckets: 10 }); // status is calculated every time status is accessed const status = circuit.status // print the entire statistical window console.log(status.window); // print the rolling stats console.log(status.stats);

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Status

// print the rolling stats console.log(status.stats); // { failures: 3, // fallbacks: 4, // successes: 44, // rejects: 4, // fires: 48, // timeouts: 1, // cacheHits: 0, // cacheMisses: 0 }

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Dashboard

http://techblog.netflix.com/2012/12/hystrix-dashboard-and-turbine.html

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Demo

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Obrigado & Questions

http://lanceball.com/qcon-saopaulo-2017/ https://github.com/lance/qcon-saopaulo-2017 Twitter - @lanceball GitHub - @lance