[RubyWine #1] Event-Driven Architecture and Messaging Patterns for Ruby Microservices

How to choose a communication protocol for services? Synchronous vs Asynchronous approach. HTTP, Brokered Messaging and gRPC. Issues when working with Threads and asynchronous message queues in Ruby and their solutions. Logging and monitoring of transactional integrity. Publish/Subscribe messaging systems and a brief comparison of them.

Video - https://youtu.be/e9AAUy4kkek

Transcript

1. Event-Driven Architecture
   Event-Driven Architecture
   Messaging Patterns for Ruby Microservices
   https://bit.ly/2RSudnT
   Kirill Shevchenko
   Kirill Shevchenko
   

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2. Who I am
   Who I am
   Ruby/JS developer, Tech Lead at
   

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3. Who I am
   Who I am
   Ruby/JS developer, Tech Lead at
   Two years with Microservices
   

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4. Who I am
   Who I am
   Ruby/JS developer, Tech Lead at
   Two years with Microservices
   Maintainer of Ruby/Rails digest on
   

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5. Who I am
   Who I am
   Ruby/JS developer, Tech Lead at
   Two years with Microservices
   Maintainer of Ruby/Rails digest on
   Live in Dnipro, Ukraine
   

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6. Who I am
   Who I am
   Ruby/JS developer, Tech Lead at
   Two years with Microservices
   Maintainer of Ruby/Rails digest on
   Live in Dnipro, Ukraine
   kirill_shevch
   

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7. Who I am
   Who I am
   Ruby/JS developer, Tech Lead at
   Two years with Microservices
   Maintainer of Ruby/Rails digest on
   Live in Dnipro, Ukraine
   kirillshevch
   kirill_shevch
   

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8. Agenda
   Agenda
   Road from Monolith to Microservices
   Communication Patterns
   Message Brokers
   Publish/Subscribe
   Testing and Monitoring
   

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9. Microservices Are
   Microservices Are
   Something You Grow Into,
   Something You Grow Into,
   Not Begin With
   Not Begin With
   

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10. Let The Adventure
    Let The Adventure
    Begin
    Begin
    

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11. "Hello World" Setup
    "Hello World" Setup
    +
    

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12. "Hello World" Setup
    "Hello World" Setup
    

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13. Background Jobs
    Background Jobs
    +
    

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14. Background Jobs
    Background Jobs
    

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15. Cache
    Cache
    

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16. Business logic size
    Business logic size
    Orders?
    

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17. Business logic size
    Business logic size
    Products?
    Orders?
    

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18. Business logic size
    Business logic size
    Analytics?
    Products?
    Orders?
    

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19. Business logic size
    Business logic size
    Analytics?
    Products?
    Orders?
    Users?
    

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20. Applying DDD to Microservices
    Applying DDD to Microservices
    

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21. Pattern: Database Per Service
    Pattern: Database Per Service
    

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22. Pattern: Database Per Service
    Pattern: Database Per Service
    

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23. Pattern: Database Per Service
    Pattern: Database Per Service
    

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24. Messaging Patterns
    Messaging Patterns
    

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25. Sync vs Async Approach
    Sync vs Async Approach
    Two Ways
    Two Ways
    

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26. Sync vs Async Approach
    Sync vs Async Approach
    Two Ways
    Two Ways
    The publisher writes a message and waits until reader
    confirm the reading
    

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27. Sync vs Async Approach
    Sync vs Async Approach
    Two Ways
    Two Ways
    The publisher writes a message and waits until reader
    confirm the reading
    The writer doesn't wait for the reader, you can read
    the message at any time
    

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28. Synchronous Calls
    Synchronous Calls
    Probably, easiest communication pattern to
    Probably, easiest communication pattern to
    implement is simply calling another service
    implement is simply calling another service
    synchronously, usually via REST.
    synchronously, usually via REST.
    Service 1 Service 2
    REST
    

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29. Synchronous Calls
    Synchronous Calls
    Protocols
    Protocols
    HTTP/RPC
    HTTP/RPC
    

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30. Synchronous Calls
    Synchronous Calls
    Protocols
    Protocols
    HTTP/RPC
    HTTP/RPC
    except for
    except for
    streaming
    streaming
    

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31. HTTP/REST IS GREAT
    HTTP/REST IS GREAT
    Easy to understand (text protocol)
    Web infrastructure already built on top of HTTP
    Great tooling for testing, inspection, modification
    Loose coupling between clients/server makes changes easy
    High-quality http implementations in every language
    

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32. Synchronous Calls
    Synchronous Calls
    Problems?
    Problems?
    You need wait for a response
    You need to handle errors (like timeouts)
    You work with many different APIs
    You you use a lot of different API wrappers
    

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33. A gem for building API Wrappers in Ruby
    A gem for building API Wrappers in Ruby
    

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34. ApiStruct: Configuration
    ApiStruct: Configuration
    ApiStruct::Settings.configure do |config|
    config.endpoints = {
    some_api: {
    root: 'https://someapi.dev/v1'
    }
    }
    end
    

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35. ApiStruct: Client
    ApiStruct: Client
    class OrdersClients < ApiStruct::Client
    some_api :orders
    def index
    get
    end
    def show(id)
    get(id)
    end
    end
    

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36. ApiStruct: Entity
    ApiStruct: Entity
    class Order < ApiStruct::Entity
    client_service OrdersClient
    attr_entity :id, :state, :total_price
    end
    

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37. ApiStruct: Entity
    ApiStruct: Entity
    class Order < ApiStruct::Entity
    client_service OrdersClient
    attr_entity :id, :state, :total_price
    end
    order = Order.show(1)
    # => {"id"=>1, "state"=>"shipping",
    "total_price"=>"99"}
    

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38. Event-Driven Architecture
    Event-Driven Architecture
    (
    (EDA
    EDA)
    )
    

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39. Сommunication Сoncepts
    Сommunication Сoncepts
    Messages
    Messages
    Events
    Events
    Commands
    Commands
    

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40. Messages
    Messages
    The basic unit of communication in Message Brokers
    The basic unit of communication in Message Brokers
    

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41. Messages
    Messages
    The basic unit of communication in Message Brokers
    The basic unit of communication in Message Brokers
    Literally can be anything
    Literally can be anything
    

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42. Messages
    Messages
    The basic unit of communication in Message Brokers
    The basic unit of communication in Message Brokers
    Literally can be anything
    Literally can be anything
    An ID, a string, an object, a
    An ID, a string, an object, a
    command, an event or whatever.
    command, an event or whatever.
    

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43. Commands
    Commands
    It's a one-to-one communication between publisher
    It's a one-to-one communication between publisher
    and subscriber
    and subscriber
    

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44. Commands
    Commands
    It's a one-to-one communication between publisher
    It's a one-to-one communication between publisher
    and subscriber
    and subscriber
    Event
    Publisher
    Subscriber
    

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45. Events
    Events
    An event is a message which informs listeners about
    An event is a message which informs listeners about
    something which has happened
    something which has happened
    

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46. Events
    Events
    An event is a message which informs listeners about
    An event is a message which informs listeners about
    something which has happened
    something which has happened
    Event
    Publisher
    Subscriber 1 Subscriber 2
    

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47. Topic
    Topic Queue
    Queue
    vs
    

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48. Topic
    Topic Queue
    Queue
    vs
    All subscribers will receive a
    All subscribers will receive a
    copy of the message
    copy of the message
    

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49. All subscribers will receive a
    All subscribers will receive a
    copy of the message
    copy of the message
    A single message will be
    A single message will be
    received by exactly one
    received by exactly one
    consumer
    consumer
    Topic
    Topic Queue
    Queue
    vs
    

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50. Queues
    Queues
    Pros
    Pros
    Simple messaging pattern with a
    transparent communication flow
    Messages can be recovered by
    putting them back on the queue
    

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51. Cons
    Cons
    Only one consumer can get the
    message
    Implies a coupling between
    producer and consumer as it’s
    an one-to-one relation
    Queues
    Queues
    

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52. Topics
    Topics
    Pros
    Pros
    Multiple consumers can get a
    message
    Decoupling between producer
    and consumers (publish-and-
    subscribe pattern)
    

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53. Cons
    Cons
    More complicated
    communication flow
    A message cannot be recovered
    for a single listener
    Topics
    Topics
    

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54. Virtual Topics
    Virtual Topics
    Pros
    Pros
    Multiple consumers can get a message
    Decoupling between producer and
    consumers (publish-and-subscribe
    pattern)
    Messages can be recovered by putting
    them back on the queue
    

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55. Virtual Topics
    Virtual Topics
    Cons
    Cons
    Might require additional
    configuration in the broker
    

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56. FIFO (First-In-First-Out)
    FIFO (First-In-First-Out)
    Queues
    Queues
    The order in which messages are sent
    and received is strictly preserved.
    

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57. Message Brokers
    Message Brokers
    

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58. Checklist
    Checklist
    Services discovery
    Messaging
    Load balancing
    Logging
    Queuing
    

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59. ACTIVE
    Apache
    MQ
    

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60. Amazon SQS
    Amazon SQS
    Fully managed message queue
    Fully managed message queue
    

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61. Amazon SQS
    Amazon SQS
    Fully managed message queue
    Fully managed message queue
    Pros
    Pros Cons
    Cons
    

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62. Amazon SQS
    Amazon SQS
    Fully managed message queue
    Fully managed message queue
    Pros
    Pros
    Available as a cloud service
    Cons
    Cons
    

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63. Amazon SQS
    Amazon SQS
    Fully managed message queue
    Fully managed message queue
    Pros
    Pros
    Available as a cloud service
    Cons
    Cons
    FIFO queues support only 300
    messages per second
    

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64. Amazon SQS
    Amazon SQS
    Fully managed message queue
    Fully managed message queue
    Pros
    Pros
    Available as a cloud service
    Cons
    Cons
    FIFO queues support only 300
    messages per second
    No ability to use FIFO with
    Pub/Sub (SNS)
    

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65. ACTIVE
    Apache
    MQ
    

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66. ActiveMQ
    ActiveMQ
    Pros
    Pros
    It has two main concepts: topics
    and queues
    

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67. ActiveMQ
    ActiveMQ
    Pros
    Pros
    It has two main concepts: topics
    and queues
    Load Balancing: replication,
    horizontal scaling
    

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68. ActiveMQ
    ActiveMQ
    Pros
    Pros
    It has two main concepts: topics
    and queues
    Load Balancing: replication,
    horizontal scaling
    Support for most protocols
    

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69. ActiveMQ
    ActiveMQ
    Pros
    Pros
    It has two main concepts: topics
    and queues
    Load Balancing: replication,
    horizontal scaling
    Support for most protocols
    Cons
    Cons
    Need backups
    

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70. ActiveMQ
    ActiveMQ
    Pros
    Pros
    It has two main concepts: topics
    and queues
    Load Balancing: replication,
    horizontal scaling
    Support for most protocols
    Cons
    Cons
    Need backups
    Might require additional
    configuration(FIFO, Virtual Topics)
    

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71. Protocols
    Protocols
    

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72. Protocols
    Protocols
    OpenWire
    OpenWire
    STOMP
    STOMP
    AMQP
    AMQP
    MQTT
    MQTT
    What to сhoose?
    What to сhoose?
    WebSocket
    WebSocket
    XMPP
    XMPP
    

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73. ActiveMQ
    ActiveMQ
    Instance can provide
    Instance can provide
    all protocols at the
    all protocols at the
    same time
    same time
    

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74. ActiveMQ
    ActiveMQ
    Endpoints
    Endpoints
    

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75. Publish/Subscribe
    Publish/Subscribe
    pattern and Ruby
    pattern and Ruby
    

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76. Publishing is simply
    Publishing is simply
    options = {
    command: 'update_order',
    data: { order_id: 1, state: :paid }
    }
    redis = Redis.new
    redis.publish(:orders, options.to_json)
    

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77. But we need handle
    But we need handle
    pubishing result
    pubishing result
    options = {
    command: 'update_order',
    data: { order_id: 1, state: :paid }
    }
    redis = Redis.new
    redis.publish(:orders, options.to_json).tap do |r|
    Raven.capture_message('Publish failed', extra: options) if r.zero?
    end
    

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78. Pub/Sub pattern
    Pub/Sub pattern
    redis = Redis.new
    redis.subscribe(:orders) do |on|
    on.message do |channel, message|
    # call the command
    end
    end
    

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79. Pub/Sub pattern
    Pub/Sub pattern
    redis = Redis.new
    Thread.new do
    redis.subscribe(:orders) do |on|
    on.message do |channel, message|
    begin
    # call the command
    rescue StandardError => e
    Raven.capture_exception(e)
    end
    end
    end
    end
    

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80. Testing
    Testing
    

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82. Real life problems
    Real life problems
    No one really knows how to test
    microservices
    

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83. Real life problems
    Real life problems
    No one really knows how to test
    microservices
    No one really knows how to test
    infrastructure for microservices
    

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84. Solutions?
    Solutions?
    Unit testing for each service with hard
    mocking
    

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85. Solutions?
    Solutions?
    Unit testing for each service with hard
    mocking
    Up the server with all services for
    running integration testing
    

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86. Monitoring
    Monitoring
    No more single system, no more centralized
    monitoring
    

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87. Monitoring
    Monitoring
    No more single system, no more centralized
    monitoring
    Logs and metrics collecting (Beats, Statsd,
    Elasticsearch)
    

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88. Monitoring
    Monitoring
    No more single system, no more centralized
    monitoring
    Logs and metrics collecting (Beats, Statsd,
    Elasticsearch)
    Aggregation (Logstash)
    

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89. Monitoring
    Monitoring
    No more single system, no more centralized
    monitoring
    Logs and metrics collecting (Beats, Statsd,
    Elasticsearch)
    Aggregation (Logstash)
    Visualization (Kibana, Grafana)
    

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90. Monitoring
    Monitoring
    No more single system, no more centralized
    monitoring
    Logs and metrics collecting (Beats, Statsd,
    Elasticsearch)
    Aggregation (Logstash)
    Visualization (Kibana, Grafana)
    Store and maintain all this data and systems
    

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91. Thanks!
    Thanks!
    

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