Pulls messages from a PubSub subscription and passes them through XCom. Always waits for at least one message to be returned from the subscription.

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Last Updated: Jan. 23, 2023

Access Instructions

Install the Google provider package into your Airflow environment.

Import the module into your DAG file and instantiate it with your desired params.


project_idRequiredthe Google Cloud project ID for the subscription (templated)
subscriptionRequiredthe Pub/Sub subscription name. Do not include the full subscription path.
max_messagesThe maximum number of messages to retrieve per PubSub pull request
ack_messagesIf True, each message will be acknowledged immediately rather than by any downstream tasks
gcp_conn_idThe connection ID to use connecting to Google Cloud.
delegate_toThe account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled.
messages_callback(Optional) Callback to process received messages. It’s return value will be saved to XCom. If you are pulling large messages, you probably want to provide a custom callback. If not provided, the default implementation will convert ReceivedMessage objects into JSON-serializable dicts using google.protobuf.json_format.MessageToDict function.
impersonation_chainOptional service account to impersonate using short-term credentials, or chained list of accounts required to get the access_token of the last account in the list, which will be impersonated in the request. If set as a string, the account must grant the originating account the Service Account Token Creator IAM role. If set as a sequence, the identities from the list must grant Service Account Token Creator IAM role to the directly preceding identity, with first account from the list granting this role to the originating account (templated).


Pulls messages from a PubSub subscription and passes them through XCom. Always waits for at least one message to be returned from the subscription.

See also

For more information on how to use this operator, take a look at the guide: Pulling messages from a PubSub subscription

See also

If you don’t want to wait for at least one message to come, use Operator instead: PubSubPullOperator

This sensor operator will pull up to max_messages messages from the specified PubSub subscription. When the subscription returns messages, the poke method’s criteria will be fulfilled and the messages will be returned from the operator and passed through XCom for downstream tasks.

If ack_messages is set to True, messages will be immediately acknowledged before being returned, otherwise, downstream tasks will be responsible for acknowledging them.

If you want a non-blocking task that does not to wait for messages, please use PubSubPullOperator instead.

project_id and subscription are templated so you can use variables in them.

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