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Grand Central connectors are vendor-agnostic Camel-K integrations packaged as Quarkus apps and Helm charts. Building one means setting up the project, laying out the route anatomy, calling REST endpoints through the standard kamelet, applying Enterprise Integration Patterns (EIPs), mapping requests and responses, configuring runtime properties, and testing locally and on a cluster. If you don’t have GitHub access to the source repositories, every compiled artifact is available from the JFrog repository at Grand Central artifacts on JFrog. This includes the BOM, SDK, kamelets, API specs, and Maven plugins.

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Build path

Code standards

Coding standards and best practices to apply across all connectors

Set up the project

Naming conventions, project layout, prerequisites, connector styles, and first-time configuration

Anatomy of a connector

The route skeleton and operation patterns for REST/JSON, SOAP/XML, and event connectors

Call REST endpoints

Use the gc-http-caller kamelet for every outbound REST call

Use Camel EIPs

Common Enterprise Integration Patterns: choice, multicast, splitter, doTry, and more

Transform and validate data

JSON Schema validation, JOLT and XSLT transformations, and helper bean calls

Configure properties

Common application.properties values for Camel, HTTP, CXF, retries, and headers

Configure a custom connector

Helm and SOPS configuration that takes effect at deploy time

Test and validate

Run the connector locally, deploy with kamel:dev, and write SDK-based unit tests

Reference artifacts and rules

Maven artifacts published to JFrog and the rules and anti-patterns to follow

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Connector styles

Three connector styles exist — REST/JSON, SOAP/XML, and Event/Generic — and the vendor’s integration type determines which to use. Each style pairs a transformation format (JOLT or XSLT) with the appropriate HTTP kamelet. For the full comparison and the exact kamelet to use for each style, see Connector styles in Set up the project.

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Technology stack

Build custom connectors with the following stack:
  • Apache Camel-K: integration framework for Kubernetes
  • Quarkus: runtime
  • Maven: build and dependency management
  • Java: primary development language
  • GitHub Actions: continuous integration and deployment