207 lines
4.3 KiB
Markdown
207 lines
4.3 KiB
Markdown
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---
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# Workshop Agenda
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## Why Baker? (10 minutes)
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## Develop an Intuition for Baker (15 m.)
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## Implement a Web Shop Flow (25 m.)
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---
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# Why Baker?
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---
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## Our Challenge
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### Interact with 12 Different Systems (complex environment)
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### A Flow of 27 Steps (difficult to reason about the logic)
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### From 2 minutes to 6 hours (stateful...)
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## Requirements
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### TIBCO is contained
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### Java developers
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### State in two data-centres
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### Systems fail all the time
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---
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| Current Account | Savings Account | Customer Onboarding |
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| :--- | :---: | ---: |
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| Verify Identity | Verify Identity | Verify Identity |
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| Register Individual | Register Individual | Register Individual |
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| Open *Current* Account | Open *Savings* Account | `n/a` |
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| Issue Debit Card | `n/a` | `n/a` |
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| Send Message | Send Message | Send Message |
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| Register Ownership | Register Ownership | `n/a` |
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---
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---
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## Baker is a Scala Library
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### Declare the Logic Like a Recipe
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### Visualize the Logic
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### Don't Worry About Retries and State
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### Re-use What's Already There
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---
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# Recipes
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## Events
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## Ingredients
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## Interactions
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# What is an Event?
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## It's what happens
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## Sensory and System Events
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# What is an Ingredient?
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## It's a container for data
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## Can be a primitive type or a POJO
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---
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# What is an Interaction?
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## It's where you put your system calls
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## Capability, not a technical call
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---
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# Hands-On
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## Setup Environment
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## Explain the Web-shop Flow
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## Exercise, Make Unit-tests Green
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## Setup Environment
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- clone https://github.com/nikolakasev/workshop-baker
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- mvn clean test
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- tests fail on purpose
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- do the [exercises](#exercises) to get them green
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---
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[.background-color: #FFFFFF]
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---
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[.background-color: #FFFFFF]
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---
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[.background-color: #FFFFFF]
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---
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[.background-color: #FFFFFF]
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---
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[.background-color: #FFFFFF]
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---
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<a name="exercises"/>
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## Exercises
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1. Put all interactions in the recipe
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2. Include sensory events in the recipe, use withSensoryEvents()
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3. Add extra conditions when an interaction must be executed, use withRequiredEvent()
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4. Change the customerInfo class from String to a POJO
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---
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[.background-color: #FFFFFF]
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# 5. Call the Postoffice and Accountant Systems in parallel
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---
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# What Can Go Wrong?
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---
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[.background-color: #FFFFFF]
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# Recipe has no sensory input, Baker doesn't know where the data comes from
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[.background-color: #FFFFFF]
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# Which two interactions will be executed when the OrderPlaced event occurs? Is this the desired behavior?
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# Desired Recipe
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---
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[.background-color: #FFFFFF]
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---
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# Food for Thought
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- What to do when the order is invalid?
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- Baker helps developers think about rainy-day scenarios
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- What if systems fails, what is desired?
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- See withFailureStrategy(), withDefaultFailureStrategy() methods and InteractionFailureStrategy class
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---
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# Food for Thought / 2
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- How to agree on functionality with stakeholders?
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- Baker represents the Java logic visually
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- How to change existing functionality? How to be confident nothing breaks?
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- Baker validates the recipe and reports inconsistencies (such as missing ingredients)
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---
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# Good to Know
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---
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## Short-lived vs. long-running flows
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---
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## State is taken care of:
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- Cassandra for persistent storage
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- Ingredients encrypted by default
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- State recovered automatically
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- Configurable Time-to-live
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---
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## When failure occurs:
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- Baker retries technical failures with exponential backoff
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- Any Java Exception thrown is a technical failure
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- Retrying works well with **idempotent** services
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- Deal with functional failure in your recipe
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---
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## Baker Catalogue: Some Stats
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### Internal ING library
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### 80+ Re-usable Interactions
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### 10+ Teams Using Baker
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---
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## Baker vs. PEGA
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| Baker | PEGA |
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| :--- | :---: |
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| Computer | Computer + Human |
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| Focused on APIs | Focused on processes |
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| No License Costs | License Costs |
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| No Usage Costs | Pay per Case Costs |
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| For Java Developers | For PEGA Specialists |
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| From ING | From PEGA |
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