Durable Task Client SDK for Java

This repo contains the Java SDK for the Durable Task Framework as well as classes and annotations to support running Azure Durable Functions for Java. With this SDK, you can define, schedule, and manage durable orchestrations using ordinary Java code.

Simple, fault-tolerant sequences

// *** Simple, fault-tolerant, sequential orchestration ***Stringresult = "";
result += ctx.callActivity("SayHello", "Tokyo", String.class).await() + ", ";
result += ctx.callActivity("SayHello", "London", String.class).await() + ", ";
result += ctx.callActivity("SayHello", "Seattle", String.class).await();
returnresult;

Replay-safe orchestration logging

Orchestrator code re-executes while rebuilding state from history. Wrap an existing java.util.logging.Logger to suppress log output during those replay segments:

Loggerlogger = ctx.createReplaySafeLogger(
Logger.getLogger(MyOrchestration.class.getName()));
logger.info(() -> "Starting orchestration " + ctx.getInstanceId());
Stringresult = ctx.callActivity("ProcessItem", input, String.class).await();
logger.info(() -> "Activity returned: " + result);

In Azure Functions, pass ExecutionContext.getLogger() instead of creating a named logger so the output retains its invocation ID and normal host routing:

Loggerlogger = ctx.createReplaySafeLogger(executionContext.getLogger());

Replay-safe logging suppresses calls made while replaying; it does not guarantee exactly-once log delivery across failed or retried live orchestration turns.

Reliable fan-out / fan-in orchestration pattern

// Get the list of work-items to processList<?> batch = ctx.callActivity("GetWorkBatch", List.class).await();
// Schedule each task to run in parallelList<Task<Integer>> parallelTasks = batch.stream()
.map(item -> ctx.callActivity("ProcessItem", item, Integer.class))
.collect(Collectors.toList());
// Wait for all tasks to complete, then return the aggregated sum of the resultsList<Integer> results = ctx.allOf(parallelTasks).await();
returnresults.stream().reduce(0, Integer::sum);

Long-running human interaction pattern (approval workflow)

ApprovalInfoapprovalInfo = ctx.getInput(ApprovalInfo.class);
ctx.callActivity("RequestApproval", approvalInfo).await();
Durationtimeout = Duration.ofHours(72);
try {
// Wait for an approval. A TaskCanceledException will be thrown if the timeout expires.booleanapproved = ctx.waitForExternalEvent("ApprovalEvent", timeout, boolean.class).await();
approvalInfo.setApproved(approved);
ctx.callActivity("ProcessApproval", approvalInfo).await();
} catch (TaskCanceledExceptiontimeoutEx) {
ctx.callActivity("Escalate", approvalInfo).await();
}

Eternal monitoring orchestration

JobInfojobInfo = ctx.getInput(JobInfo.class);
StringjobId = jobInfo.getJobId();
Stringstatus = ctx.callActivity("GetJobStatus", jobId, String.class).await();
if (status.equals("Completed")) {
// The job is done - we can exit nowctx.callActivity("SendAlert", jobId).await();
} else {
// wait N minutes before doing the next pollDurationpollingDelay = jobInfo.getPollingDelay();
ctx.createTimer(pollingDelay).await();
// restart from the beginningctx.continueAsNew(jobInfo);
}
returnnull;

Maven Central packages

The following packages are produced from this repo.

Package	Latest version
Durable Task - Client
Durable Task - Azure Functions

Getting started with Azure Functions

For information about how to get started with Durable Functions for Java, see the Azure Functions README.md content.

Contributing

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