csharp

Camunda Platform 8 - Get Started - C# Client

This guide explains how to setup a csharp project to automate a process using Camunda Platform 8.

For the complete code see the Program.cs file. You can run it using the following command.

dotnet run

Install dependencies

The open source library zeebe-client-csharp provides a Zeebe client. The nuget package is called zb-client and can be found here.

Create Client

If we want to connect to a Camunda Platform 8 SaaS cluster we need the contact point, also know as ZEEBE_ADDRESS. Furthermore we need the clientId and clientSecret all these information we get from the client credentials.

The credentails can be specified in the client builder.

IZeebeClient zeebeClient = CamundaCloudClientBuilder.Builder()
        .UseClientId("kYbf5pwF3WP_ZuOU_13fde~uG7M_IaGZ")
        .UseClientSecret("1nl8HNRd8INmL4kUcMcZOPCbjk2ZNUdacsGeOOotkknHUeqV9L~1eJFztsSZ8kpq")
        .UseContactPoint("6ce770b8-cd6d-4977-854c-bff92d0d3d98.zeebe.camunda.io:443")
        .Build();

Deploy Process and Start Instance

To deploy a process you can use the NewDeployCommand method, which allows to specify a list of resources, which should be deployed.

await zeebeClient.NewDeployCommand()
        .AddResourceFile("send-email.bpmn")
        .Send();

To start a new instance you can specify the bpmnProcessId, i.e. send-email and optionally process variables.

var processInstanceResponse = await zeebeClient
          .NewCreateProcessInstanceCommand()
          .BpmnProcessId("send-email")
          .LatestVersion()
          .Variables(variables)
          .Send();

Job Worker

To complete a service task, a job worker has to be subscribed to the task type defined in the process, i.e. email. For this the NewWorker method can be used.

zeebeClient.NewWorker()
           .JobType("email")
           .Handler(JobHandler)
           .MaxJobsActive(3)
           .Timeout(TimeSpan.FromSeconds(10))
           .PollInterval(TimeSpan.FromMinutes(1))
           .PollingTimeout(TimeSpan.FromSeconds(30))
           .Name("CsharpGetStartedWorker")
           .Open()

The job worker will call for each activated job the specified job handler, which can look like this:

void JobHandler(IJobClient jobClient, IJob activatedJob)
{
    var variables = JsonConvert.DeserializeObject<Dictionary<string, string>>(activatedJob.Variables);

    Log.LogInformation($"Sending email with message content: {variables[VariablesKey]}");

    jobClient.NewCompleteJobCommand(activatedJob).Send();
}

To make an job available for that job worker, a user task has to be completed, follow the instructions in the guide.