Durable Functions (Azure Functions) 中的子協調流程

除了呼叫活動函式，協調器函式還可以呼叫其他協調器函式。 例如，您可以從更小的協調器函式程式庫中編譯更大的協調流程。 或者，也可以平行執行協調器函式的多個執行個體。

協調器函式可使用 "call-sub-orchestrator" API 呼叫另一個協調器函式。 錯誤處理和補償一文提供自動重試的詳細資訊。

從呼叫端的觀點來看，子協調器函式的行為就像活動函式一樣。 子協調器函式可以傳回值、擲回例外狀況，還可以由父代協調器函式來等候。

注意

PowerShell 尚不支援子協調流程。

注意

適用於 Azure Functions 的第 4 版 Node.js 程式設計模型已正式推出。 新的 v4 模型旨在為 JavaScript 和 TypeScript 開發人員提供更靈活的直覺式體驗。 如需深入了解 v3 與 v4 之間的差異，請參閱移轉指南。

在下列程式碼片段中，JavaScript (PM4) 表示程式設計模型 V4，這是新的體驗。

範例

下列範例說明 IoT (物聯網) 情節，其中有多個需要佈建的裝置。 下列函式代表每個裝置必須執行的佈建工作流程：

C# (內含式)

public static async Task DeviceProvisioningOrchestration(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
{
    string deviceId = context.GetInput<string>();

    // Step 1: Create an installation package in blob storage and return a SAS URL.
    Uri sasUrl = await context.CallActivityAsync<Uri>("CreateInstallationPackage", deviceId);

    // Step 2: Notify the device that the installation package is ready.
    await context.CallActivityAsync("SendPackageUrlToDevice", Tuple.Create(deviceId, sasUrl));

    // Step 3: Wait for the device to acknowledge that it has downloaded the new package.
    await context.WaitForExternalEvent<bool>("DownloadCompletedAck");

    // Step 4: ...
}

C# (隔離式)

public static async Task DeviceProvisioningOrchestration(
    [OrchestrationTrigger] TaskOrchestrationContext context, string deviceId)
{
    // Step 1: Create an installation package in blob storage and return a SAS URL.
    Uri sasUrl = await context.CallActivityAsync<Uri>("CreateInstallationPackage", deviceId);

    // Step 2: Notify the device that the installation package is ready.
    await context.CallActivityAsync("SendPackageUrlToDevice", (deviceId, sasUrl));

    // Step 3: Wait for the device to acknowledge that it has downloaded the new package.
    await context.WaitForExternalEvent<bool>("DownloadCompletedAck");

    // Step 4: ...
}

JavaScript (PM3)

const df = require("durable-functions");

module.exports = df.orchestrator(function*(context) {
    const deviceId = context.df.getInput();

    // Step 1: Create an installation package in blob storage and return a SAS URL.
    const sasUrl = yield context.df.callActivity("CreateInstallationPackage", deviceId);

    // Step 2: Notify the device that the installation package is ready.
    yield context.df.callActivity("SendPackageUrlToDevice", { id: deviceId, url: sasUrl });

    // Step 3: Wait for the device to acknowledge that it has downloaded the new package.
    yield context.df.waitForExternalEvent("DownloadCompletedAck");

    // Step 4: ...
});

JavaScript (PM4)

const df = require("durable-functions");

df.app.orchestration("deviceProvisioningOrchestration", function* (context) {
    const deviceId = context.df.getInput();

    // Step 1: Create an installation package in blob storage and return a SAS URL.
    const sasUrl = yield context.df.callActivity("createInstallationPackage", deviceId);

    // Step 2: Notify the device that the installation package is ready.
    yield context.df.callActivity("sendPackageUrlToDevice", { id: deviceId, url: sasUrl });

    // Step 3: Wait for the device to acknowledge that it has downloaded the new package.
    yield context.df.waitForExternalEvent("downloadCompletedAck");

    // Step 4: ...
});

Python

import azure.functions as func
import azure.durable_functions as df

def orchestrator_function(context: df.DurableOrchestrationContext):
    device_id = context.get_input()

    # Step 1: Create an installation package in blob storage and return a SAS URL.
    sas_url = yield context.call_activity("CreateInstallationPackage", device_id)

    # Step 2: Notify the device that the installation package is ready.
    yield context.call_activity("SendPackageUrlToDevice", { "id": device_id, "url": sas_url })

    # Step 3: Wait for the device to acknowledge that it has downloaded the new package.
    yield context.call_activity("DownloadCompletedAck")

    # Step 4: ...

Java

@FunctionName("DeviceProvisioningOrchestration")
public void deviceProvisioningOrchestration(
        @DurableOrchestrationTrigger(name = "ctx") TaskOrchestrationContext ctx) {
    // Step 1: Create an installation package in blob storage and return a SAS URL.
    String deviceId = ctx.getInput(String.class);
    String blobUri = ctx.callActivity("CreateInstallPackage", deviceId, String.class).await();

    // Step 2: Notify the device that the installation package is ready.
    String[] args = { deviceId, blobUri };
    ctx.callActivity("SendPackageUrlToDevice", args).await();

    // Step 3: Wait for the device to acknowledge that it has downloaded the new package.
    ctx.waitForExternalEvent("DownloadCompletedAck").await();

    // Step 4: ...
}

這個協調器函式可直接用於一次性裝置佈建，也可以當作更大協調流程的一部分。 在後者的情況下，父協調器函式可使用 "call-sub-orchestrator" API 來排程 DeviceProvisioningOrchestration 的執行個體。

以下示範如何平行執行多個協調器函式。

C# (內含式)

[FunctionName("ProvisionNewDevices")]
public static async Task ProvisionNewDevices(
    [OrchestrationTrigger] IDurableOrchestrationContext context)
{
    string[] deviceIds = await context.CallActivityAsync<string[]>("GetNewDeviceIds");

    // Run multiple device provisioning flows in parallel
    var provisioningTasks = new List<Task>();
    foreach (string deviceId in deviceIds)
    {
        Task provisionTask = context.CallSubOrchestratorAsync("DeviceProvisioningOrchestration", deviceId);
        provisioningTasks.Add(provisionTask);
    }

    await Task.WhenAll(provisioningTasks);

    // ...
}

注意

先前的 C# 範例適用於 Durable Functions 2.x。 針對 Durable Functions 1.x，您必須使用 DurableOrchestrationContext 而不是 IDurableOrchestrationContext。 如需版本差異的詳細資訊，請參閱 Durable Functions 版本一文。

C# (隔離式)

[FunctionName("ProvisionNewDevices")]
public static async Task ProvisionNewDevices(
    [OrchestrationTrigger] TaskOrchestrationContext context)
{
    string[] deviceIds = await context.CallActivityAsync<string[]>("GetNewDeviceIds");

    // Run multiple device provisioning flows in parallel
    var provisioningTasks = new List<Task>();
    foreach (string deviceId in deviceIds)
    {
        Task provisionTask = context.CallSubOrchestratorAsync("DeviceProvisioningOrchestration", deviceId);
        provisioningTasks.Add(provisionTask);
    }

    await Task.WhenAll(provisioningTasks);

    // ...
}

JavaScript (PM3)

const df = require("durable-functions");

module.exports = df.orchestrator(function*(context) {
    const deviceIds = yield context.df.callActivity("GetNewDeviceIds");

    // Run multiple device provisioning flows in parallel
    const provisioningTasks = [];
    var id = 0;
    for (const deviceId of deviceIds) {
        const child_id = context.df.instanceId+`:${id}`;
        const provisionTask = context.df.callSubOrchestrator("DeviceProvisioningOrchestration", deviceId, child_id);
        provisioningTasks.push(provisionTask);
        id++;
    }

    yield context.df.Task.all(provisioningTasks);

    // ...
});

JavaScript (PM4)

const df = require("durable-functions");

df.app.orchestration("provisionNewDevices", function* (context) {
    const deviceIds = yield context.df.callActivity("getNewDeviceIds");

    // Run multiple device provisioning flows in parallel
    const provisioningTasks = [];
    var id = 0;
    for (const deviceId of deviceIds) {
        const child_id = context.df.instanceId + `:${id}`;
        const provisionTask = context.df.callSubOrchestrator(
            "deviceProvisioningOrchestration",
            deviceId,
            child_id
        );
        provisioningTasks.push(provisionTask);
        id++;
    }

    yield context.df.Task.all(provisioningTasks);

    // ...
});

Python

import azure.functions as func
import azure.durable_functions as df

def orchestrator_function(context: df.DurableOrchestrationContext):

    device_IDs = yield context.call_activity("GetNewDeviceIds")

    # Run multiple device provisioning flows in parallel
    provisioning_tasks = []
    id_ = 0
    for device_id in device_IDs:
        child_id = f"{context.instance_id}:{id_}"
        provision_task = context.call_sub_orchestrator("DeviceProvisioningOrchestration", device_id, child_id)
        provisioning_tasks.append(provision_task)
        id_ += 1

    yield context.task_all(provisioning_tasks)

    # ...

Java

@FunctionName("ProvisionNewDevices")
public void provisionNewDevices(
        @DurableOrchestrationTrigger(name = "ctx") TaskOrchestrationContext ctx) {
    List<?> deviceIDs = ctx.getInput(List.class);

    // Schedule each device provisioning sub-orchestration to run in parallel
    List<Task<Void>> parallelTasks = deviceIDs.stream()
        .map(device -> ctx.callSubOrchestrator("DeviceProvisioningOrchestration", device))
        .collect(Collectors.toList());

    // ...
}

注意

子協調流程必須在與父協調流程相同的函數應用程式中定義。 如果您需要呼叫並等候另一個函數應用程式中的協調流程，請考慮使用 HTTP API 和 HTTP 202 輪詢取用者模式的內建支援。 HTTP 功能如需詳細資訊，請參閱 HTTP 功能主題。

下一步

了解如何設定自訂協調流程狀態