docs/daprdocs/content/en/developing-applications/building-blocks/pubsub/pubsub-bulk.md

type	title	linkTitle	weight	description
docs	Send and receive messages in bulk	Send and receive messages in bulk	7100	Learn how to use the bulk publish and subscribe APIs in Dapr.

{{% alert title="alpha" color="warning" %}} The bulk publish and subscribe APIs are in alpha stage. {{% /alert %}}

With the bulk publish and subscribe APIs, you can send and receive multiple messages in a single request.

Native bulk publish and subscribe support

When a pub/sub component supports the bulk publish API natively, Dapr also publishes messages to the underlying pub/sub component in bulk.

Otherwise, Dapr falls back to sending messages one by one to the underlying pub/sub component. This is still more efficient than using the regular publish API, because applications can still send multiple messages in a single request to Dapr.

Supported components

Refer to the [component reference]({{< ref supported-pubsub >}}) to see which components support the bulk publish API natively.

Publishing messages in bulk

Example

{{< tabs Java Javascript "HTTP API (Bash)" "HTTP API (PowerShell)" >}}

{{% codetab %}}

import io.dapr.client.DaprClientBuilder;
import io.dapr.client.DaprPreviewClient;
import io.dapr.client.domain.BulkPublishResponse;
import io.dapr.client.domain.BulkPublishResponseFailedEntry;
import java.util.ArrayList;
import java.util.List;

class BulkPublisher {
  public void publishMessages() {
    try (DaprPreviewClient client = (new DaprClientBuilder()).buildPreviewClient()) {
      // Create a list of messages to publish
      List<String> messages = new ArrayList<>();
      for (int i = 0; i < 10; i++) {
        String message = String.format("This is message #%d", i);
        messages.add(message);
      }

      // Publish list of messages using the bulk publish API
      BulkPublishResponse<String> res = client.publishEvents(PUBSUB_NAME, TOPIC_NAME, "text/plain", messages).block();
    }
  }
}

{{% /codetab %}}

{{% codetab %}}

import { DaprClient } from "@dapr/dapr";

const pubSubName = "my-pubsub-name";
const topic = "topic-a";

async function start() {
    const client = new DaprClient();

    // Publish multiple messages to a topic.
    await client.pubsub.publishBulk(pubSubName, topic, ["message 1", "message 2", "message 3"]);

    // Publish multiple messages to a topic with explicit bulk publish messages.
    const bulkPublishMessages = [
    {
      entryID: "entry-1",
      contentType: "application/json",
      event: { hello: "foo message 1" },
    },
    {
      entryID: "entry-2",
      contentType: "application/cloudevents+json",
      event: { 
        specversion: "1.0",
        source: "/some/source",
        type: "example",
        id: "1234", 
        data: "foo message 2", 
        datacontenttype: "text/plain" 
      },
    },
    {
      entryID: "entry-3",
      contentType: "text/plain",
      event: "foo message 3",
    },
  ];
  await client.pubsub.publishBulk(pubSubName, topic, bulkPublishMessages);
}

start().catch((e) => {
  console.error(e);
  process.exit(1);
});

{{% /codetab %}}

{{% codetab %}}

curl -X POST http://localhost:3500/v1.0-alpha1/publish/bulk/my-pubsub-name/topic-a \
  -H 'Content-Type: application/json' \
  -d '[
        {
            "entryId": "ae6bf7c6-4af2-11ed-b878-0242ac120002",
            "event":  "first",
            "contentType": "text/plain"
        },
        {
            "entryId": "b1f40bd6-4af2-11ed-b878-0242ac120002",
            "event":  {
                "message": "second"   
            },
            "contentType": "application/json"
        },
      ]'

{{% /codetab %}}

{{% codetab %}}

Invoke-RestMethod -Method Post -ContentType 'application/json' -Uri 'http://localhost:3500/v1.0-alpha1/publish/bulk/my-pubsub-name/topic-a' `
-Body '[
        {
            "entryId": "ae6bf7c6-4af2-11ed-b878-0242ac120002",
            "event":  "first",
            "contentType": "text/plain"
        },
        {
            "entryId": "b1f40bd6-4af2-11ed-b878-0242ac120002",
            "event":  {
                "message": "second"   
            },
            "contentType": "application/json"
        },
      ]'

{{% /codetab %}}

{{< /tabs >}}

Related links

• List of [supported pub/sub components]({{< ref supported-pubsub >}})
• Read the [API reference]({{< ref pubsub_api.md >}})