Speaker: "Using the Mule 4 SDK to build a connector" session with Chris Hughes, Strategic Advisor at MuleSoft Host: Angel Alberici Youtube: Virtual Muleys (https://www.youtube.com/c/VirtualMuleysOnline/videos) Meetups: https://meetups.mulesoft.com/online-group-english/ https://meetups.mulesoft.com/events/details/mulesoft-online-group-english-presents-using-the-mule-4-java-sdk-to-build-a-connector/

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December 2020
Chris Hughes, Strategic Advisor at MuleSoft
Using the Mule 4 SDK
to build a Connector

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Agenda
1. Introduction
a. What is a Connector?
b. Mule 4 SDK for Java vs. Mule 3 DevKit
c. Best Practices
2. Mule 4 SDK Object Model
3. How to build your own Extension
4. docu-connector Code Walkthrough
5. docu-connector Demonstration
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Introduction: What is a Connector?
Mule 4 provides a well-defined mechanism to extend the runtime, by creating “modules” that
you can easily add to Mule applications.
Examples of modules include:
● Connectors, such as HTTP
● Modules, such as the Validations module
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Introduction: Mule 4 SDK vs. Mule 3 DevKit
● Mule 4 SDK replaces DevKit
● DevKit is not available for Mule 4
● Mule 4 provides XML and Java SDKs
● Mule 4 SDK makes use of Java Annotations, but is not a code generator
● Mule 4 SDK is more flexible than DevKit and supports:
○ Transactions
○ Request-Response message sources
○ Dynamic configurations
○ Routers
○ Non-blocking operations
○ Classloading isolation
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Introduction: Best Practices
General Rules:
● A connector’s purpose is to bring the target system into the Mule language
● A connector should not include operations that implement specific business use cases
● Coding Rules
○ Design for Thread Safety
○ Never Access Flow Variables
○ Never Use Message Attributes as Parameters
○ Don’t Access the MuleContext
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Mule 4 SDK Object Model
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Mule 4 SDK Object Model
Core Elements of the SDK Object Model are:
● Component
○ Given a set of parameters, a component encapsulates functionality that can be executed to
produce or alter messages in a flow
● Configuration
○ A set of parameters that affect the behaviour of the module
○ Sources and Operations may depend on a Configuration for parameters
● Connection Provider
○ Handles management of connections created from a Configuration
○ Configurations may have none, one, or many Connection Providers
● Parameter
○ A value placeholder whose context can be defined within all of the above
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How to build your own Extension
● https://docs.mulesoft.com/mule-sdk/1.1/getting-started
● Remember: a connector should be a generic extension to the Mule runtime (not specific
to a business use case)
● Consider how the target system aligns with the Mule SDK Object Model:
○ Just because the SDK provides a ConnectionProvider annotation doesn’t mean your extension
has to make use of one!
● There are some good advanced examples on GitHub, but avoid unnecessary complexity:
○ https://github.com/mulesoft/mule-email-connector
○ https://github.com/mulesoft/mule-http-connector
● Or, you could take a look at my simple DocuSign connector:
○ https://github.com/mule-org-uk/docu-connector
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Why build a DocuSign Connector?
● DocuSign already exposes a REST API
● DocuSign Authentication process is:
○ JWT-based, but
○ Requires the definition, review, and promotion of an “integrator key”
○ Relies on algorithm that would be difficult (if not impossible) to implement in DataWeave
○ Easily reusable, if defined appropriately
○ https://developers.docusign.com/platform/auth/jwt/jwt-get-token/
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Time to look at some code!
docu-connector Code Walkthrough
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Let’s see it in action!
docu-connector Demonstration
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Thank you!