​

La charla interesante es en el otro track.

​

//

​

The interesting talk it’s next door

Kitchen nightmares 🍽️

Understanding message brokers

moisesrj.dev

Moisés (Moi) Rodríguez Jurado

Software Developer Crafter

moisesrj.dev

Disclaimers

• I’m not an expert in message brokers
• I don’t know how a restaurant works
• I make ugly presentations
• It’s my first talk in a conference
• I’m pretty sure I’m going to receive some IP notice for this talk

UNIXcorn

PegaSO

PonIA

BUG

Previously on “The Bug”...

Mr. Doe

a.k.a. “The chef”

Monolith

Mr. Foo

a.k.a. “The waiter”

Before we continue…

Sender

Recipient

Channel

Feedback

Message

Episode 1:

The missing rice

Chicken sandwich!

Two cokes and some fries!

I’d go for a double burger!

Two chickens!

…

One burger

One rice, no fish

Two coffees

Two fries!

One bacon sandwich

Table 3 is missing a rice

What rice? What table 3?

Sender

Recipient

Channel

Feedback

Message

Sender

Recipient

Feedback

Sender

Recipient

Feedback

1 Chicken

2

Sandwich

1

Pizza

2

Fries

3

Salad

2

Burguer

1 Chicken

2

Sandwich

1

Pizza

2

Fries

3

Salad

2

Burguer

2

Sandwich

1

Pizza

2

Fries

3

Salad

2

Burguer

1 Chicken

Sender

Recipient

Feedback

Feedback

1 Chicken

2

Sandwich

1

Pizza

2

Fries

3

Salad

2

Burguer

2

Burger

(retry)

1 Chicken

2

Sandwich

1

Pizza

2

Fries

3

Salad

2

Burguer

2

Burger

(retry)

1 Chicken

2

Sandwich

1

Pizza

2

Fries

3

Salad

2

Burguer

2

Burger

(5th retry)

To check:

1 Chicken

2

Sandwich

1

Pizza

2

Fries

3

Salad

2

Burguer

2

Burger

(5th retry)

To check:

In the fields of engineering and construction, resilience is the ability to absorb or avoid damage without suffering complete failure and is an objective of design

Message

Message

Message�1 retry

Message�1 retry

Message�5 retry

System is malfunctioning

Malformed payload

Some other sketchy thing

Message�5 retry

Message

Producer

Consumer

Queue

Point-to-point model

Message

Producers

Consumers

Queue

Message

Message

Episode 2:

The yelling

Working on it!

Doe! Mushrooms Risotto!

Foo! New customer!

I’ve seen it!

Foo! New customer!

Doe! Mushrooms Risotto!

POST http://localhost:1234/risotto

POST http://localhost:4321/new-customer

Sender

Recipient

Channel

Feedback

Message

Screams

Working on it!

Risotto is needed

HTTP/S

201 status code

POST request�/risotto

Mrs. Bar

a.k.a. “The Bartender”

More people!

More people!

More yelling

Trade-offs with the yelling http system

🍕 Know that the other person exists

💻 Knowledge of other systems

Trade-offs with the yelling http system

🍕 Careful with misspelling!

💻 Fixed endpoints

Trade-offs with the yelling http system

🍕 Respond in the moment

💻 Synchronous responses

Trade-offs with the yelling http system

🍕 Multiple screams for complex tasks

💻 Multiple calls for a single operation/event

Smart Pagers!

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

food.rice.risotto

food.rice.*

food.*

food.rice.*

food.*

Ok, let’s cook

some food!

Rice! Let’s

have the white wine ready

food.rice.*

food.*

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

Producer

Broker

Topic/

Subscription

Consumer

Pub/Sub model

Message

Sender

Recipient

Channel

Feedback

Message

Producer

Broker

Channel: Depending on the broker

ok

Message

Producer

Broker

Channel

ok

Message

Consumer

Message

Consumer

Message

ok

ok

Message

Producer

Consumer

Queue

Point-to-point model

Remembering…

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

Producer

Broker

Topic

Consumer

Pub/Sub model

Episode 3:

The infinite chicken

food.chicken.roasted

food.*

food.*

food.*

food.*

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s cook

some food

Ok, let’s charge the client

Ok, let’s cook

some food

Ok, let’s charge the client

💀

Smart Pagers!

Smart Pagers!

I’m free! �*click*

Let’s get to work

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

Producer

Broker

Consumers

Group 1

Topic

Group 2

Group 3

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

Producer

Broker

Consumers

Group 1

Topic

Group 2

Group 3

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

Producer

Broker

Group

Consumers

Group 1

Topic

Group 2

Group 3

food.rice.risotto

food.*

food.rice.*

food.rice.risotto

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

food.

rice.

risotto

​

Producer

Broker

Queue

Consumers

Topic

Delivery models

https://blog.bytebytego.com/p/at-most-once-at-least-once-exactly

Delivery models

https://blog.bytebytego.com/p/at-most-once-at-least-once-exactly

Delivery models

https://blog.bytebytego.com/p/at-most-once-at-least-once-exactly

THE END

THE END ?

Bloopers!

What if…

• A message is not processed?
• There is a problem and a message is repeated
• The topic / queue name changes only on one side

This is the end, I promise 👉👈

What if a message is not processed?

What if a message is not processed?

Broker

Consumer

msg

Consumer

Consumer

What if a message is not processed?

Broker

Consumer

msg

Consumer

Consumer

msg

What if a message is not processed?

​

Broker

Consumer

msg

Consumer

Consumer

Retry

Send to special queue

External notification

OK / KO

Feedback!

What if there is a problem and a message is repeated?

What if there is a problem and a message is repeated?

Updating

Processing a payment

🤷‍♂️

☠️

What if there is a problem and a message is repeated?

What if there is a problem and a message is repeated?

Idempotence (UK: /ˌɪdɛmˈpoʊtəns/,^[1] US: /ˈaɪdəm-/)^[2] is the property of certain operations in mathematics and computer science whereby they can be applied multiple times without changing the result beyond the initial application.

What if the topic changes only on one side?

What if the topic changes only on one side?

What if the topic changes only on one side?

1. Enforce format
2. Creating shared, internal libraries
3. Smoke/Contract tests

THE END

This time for real 👽

Maybe we still don’t know how to cook…

But at least we know about how message brokers work!

But at least we know a bit about how message brokers work!

But at least we know a bit about how message brokers work!

Thank you for your time 💚

Kitchen nightmares 🍽️

Questions?

Understanding message brokers

moisesrj.dev