Camunda Connectors

Re-usable building blocks for safe + happy automation

Nico Rehwaldt

Camunda for Professional Developers

Implementing Behavior

var client = clientBuilder.build();

var workerRegistration =
  client
    .newWorker()
    .jobType("collect-money")
    .handler(new CollectMoneyJobHandler())
    .open();

class CollectMoneyJobHandler implements JobHandler {

  @Override
  public void handle(JobClient client, ActivatedJob job) {

    // collect that money!

    client.newCompleteCommand(job).send().join();
  }
}

Building Automation Projects

Process Application

• A project that contains all business logic and/or glue code.
• Deploys the process + registers job workers on start).
• Tested, of course (eg. zeebe-process-test).

Core Automation Takeaways

• Builder is Developer persona
• Single package contains everything
• Built using development practices
• Tested and shipped via standard CI/CD tools
• Variables are implicit (and/or in code)

A strong story and the foundation of our success

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Safe and happy automation for everyone

(Some) Needs

• Build upon existing building blocks
• Model domain specific, not engine specific
• Explicit variables + hinting
• Detailed diagram validation

Connectors

Re-usable building blocks for modeling + execution.

Modeling

➡️ Element Templates (aka "Connector Templates")

Execution

➡️ Connector SDK

Connector SDK

• Foundation for re-usable behavior ("run-time")
• Simple to use API to build against
• Simple to test
• Environment agnostic
• Adapters to run (as job worker, in C8 SaaS)
• SPIs allow to hook up shared behavior (i.e. secrets handling)

public class CollectMoneyConnector implements ConnectorFunction {

  @Override
  public Object execute(ConnectorContext context) throws Exception {

    var request = context.getVariablesAsType(CollectMoneyInput.class);

    var validator = new Validator();
    request.validate(validator);
    validator.validate();

    request.replaceSecrets(context.getSecretStore());

    // actually get that money!

    return new CollectMoneyResponse("Took " + request.getAmount() + " bucks!");
  }
}

import io.camunda.connector.runtime.jobworker.ConnectorJobHandler;
import io.camunda.zeebe.client.ZeebeClient;

public class Main {

  public static void main(String[] args) {

    var zeebeClient = ZeebeClient.newClientBuilder().build();

    zeebeClient.newWorker()
        .jobType("collect-money")
        .handler(new ConnectorJobHandler(new CollectMoneyFunction()))
        .name("collect-money")
        .fetchVariables("bucket", "amount")
        .open();
  }
}

Takeaways

• Our goal is to enable users to create + ship re-usable building blocks, but also to use what is already there (community / market place?)

• Element Templates / Connector SDK enforce best practices for implementation and ensure safe re-use

Next Steps (2022-08-15)

• Ship Element Templates: Conditional properties
• Ship (publish) Connector SDK (outbound)
• Investigate Connector SDK (inbound)
• Build more connectors (inhouse)

Footnote on Inbound

• Inbound is complicated
• ➡️ You'll see more benefits from an SDK

Thanks

❤️