Actions

The ballerinax/gcloud.pubsub package exposes the following clients:

Client	Purpose
Publisher	Publishes messages to a Google Cloud Pub/Sub topic.

For event-driven integration, see the Trigger Reference.

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Publisher

Publishes messages to a Google Cloud Pub/Sub topic.

Configuration

Field	Type	Default	Description
batchConfig	BatchConfig	()	Message batching configuration (max delay, message count, byte limit).
compression	record {| int threshold; |}	()	Compression configuration. Messages exceeding the threshold (in bytes, default 240) are compressed.
auth	GcpCredentialConfig	()	GCP service account credentials. Contains a path field pointing to the JSON key file.
enableMessageOrdering	boolean	false	Enable message ordering using ordering keys.
retryConfig	RetryConfig	()	Retry configuration with exponential backoff for publish failures.

Initializing the client

import ballerinax/gcloud.pubsub;

configurable string project = ?;
configurable string topic = ?;
configurable string gcpCredentialsFilePath = ?;

pubsub:Publisher publisher = check new (project, topic,
    auth = {path: gcpCredentialsFilePath}
);

Operations

Messaging

publish

Publishes a message to the configured Pub/Sub topic. The message data can be string, json, xml, or byte[]: non-byte types are automatically serialized.

Parameters:

Name	Type	Required	Description
message	Message	Yes	The message record containing data, optional attributes, and optional orderingKey.

Returns: string|Error

Sample code:

string messageId = check publisher->publish({
    data: "Hello from Ballerina!",
    attributes: {"source": "ballerina-app", "env": "production"}
});

Sample response:

"1234567890123456"

close

Gracefully shuts down the publisher, flushing any pending batched messages before closing.

Parameters:

Name	Type	Required	Description
timeout	decimal	No	Maximum time in seconds to wait for graceful shutdown. Defaults to 10.0.

Returns: Error?

Sample code:

check publisher->close();