Delete a schema revision for a topic

This document shows you how to delete schema revisions for Pub/Sub topics. The delete operation for a schema also deletes all the revisions associated with the schema.

Caution: Deletion is permanent. You cannot restore a schema revision that is deleted. Any messages that validated against the deleted schema revision at the time of publish cannot be written to BigQuery using a BigQuery subscription with use topic schema enabled. Instead of deleting a revision, consider rolling back a schema.

Before you begin

• Understand how Pub/Sub schemas work.
• Create a schema.

Required roles and permissions

To get the permissions that you need to delete and manage schema revisions, ask your administrator to grant you the Pub/Sub Editor (roles/pubsub.editor) IAM role on your project. For more information about granting roles, see Manage access to projects, folders, and organizations.

This predefined role contains the permissions required to delete and manage schema revisions. To see the exact permissions that are required, expand the Required permissions section:

Required permissions

The following permissions are required to delete and manage schema revisions:

• Create schema: pubsub.schemas.create
• Attach schema to topic: pubsub.schemas.attach
• Commit a schema revision: pubsub.schemas.commit
• Delete a schema or a schema revision: pubsub.schemas.delete
• Get a schema or schema revisions: pubsub.schemas.get
• List schemas: pubsub.schemas.list
• List schema revisions: pubsub.schemas.listRevisions
• Rollback a schema: pubsub.schemas.rollback
• Validate a message: pubsub.schemas.validate
• Get the IAM policy for a schema: pubsub.schemas.getIamPolicy
• Configure the IAM policy for a schema: pubsub.schemas.setIamPolicy

You might also be able to get these permissions with custom roles or other predefined roles.

You can grant roles and permissions to principals such as users, groups, domains, or service accounts. You can create a schema in one project and attach it to a topic located in a different project. Ensure that you have the required permissions for each project.

Delete a schema revision

Important: If all revisions within the revision range of the schema settings for a topic are deleted, all attempts to publish messages to that topic fail.

The following are some important guidelines for deleting a schema revision:

• You can delete one or multiple schema revisions from a schema.

• If the schema has only one revision, you cannot delete the revision. Instead, delete the schema.

• The delete operation for a schema also deletes all the revisions associated with the schema.

• If you delete a schema, publishing messages to topics associated with that schema fails.

• If you delete a schema revision, and it's specified as the first revision for a topic, the next revision is used instead for validation.

  If the deleted schema revision is specified as the last revision for a topic, the previous schema revision is used instead for validation.

  If the deleted schema revision falls within the specified revision range for a topic for validation, the revision is skipped.

You can delete a schema revision using the Google Cloud console, the gcloud CLI, the Pub/Sub API, or the Cloud Client Libraries.

Console

1. In the Google Cloud console, go to the Pub/Sub schemas page.

   Go to Schemas

2. Click the name of an existing schema.

   The Schema details page for the schema opens.

3. Select the revision that you want to delete. You can also select multiple revisions.

4. Click Delete revision.

5. Confirm the delete operation.

gcloud

gcloud pubsub schemas delete-revision SCHEMA_NAME@REVISION_ID

Where:

• REVISION_ID is the revision to which you want to roll back.

REST

To delete a schema revision, send a DELETE request like the following:

POST https://pubsub.googleapis.com/v1/projects/PROJECT_ID/schemas/SCHEMA_ID@REVISION_ID:deleteRevision
Authorization: Bearer $(gcloud auth application-default print-access-token)
Content-Type: application/json --data @response-body.json

The response body should contain a JSON representation the deleted schema resource.

C++

Before trying this sample, follow the C++ setup instructions in Quickstart: Using Client Libraries. For more information, see the Pub/Sub C++ API reference documentation.

namespace pubsub = ::google::cloud::pubsub;
[](pubsub::SchemaServiceClient client, std::string const& project_id,
   std::string const& schema_id, std::string const& revision_id) {
  std::string const schema_id_with_revision = schema_id + "@" + revision_id;

  google::pubsub::v1::DeleteSchemaRevisionRequest request;
  request.set_name(
      pubsub::Schema(project_id, schema_id_with_revision).FullName());
  auto schema = client.DeleteSchemaRevision(request);
  if (!schema) throw std::move(schema).status();

  std::cout << "Deleted schema. Its metadata is:"
            << "\n"
            << schema->DebugString() << "\n";
}

Go

Before trying this sample, follow the Go setup instructions in Quickstart: Using Client Libraries. For more information, see the Pub/Sub Go API reference documentation.

import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/pubsub"
)

func deleteSchemaRevision(w io.Writer, projectID, schemaID, revisionID string) error {
	// projectID := "my-project-id"
	// schemaID := "my-schema-id"
	// revisionID := "my-revision-id"
	ctx := context.Background()
	client, err := pubsub.NewSchemaClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("pubsub.NewSchemaClient: %w", err)
	}
	defer client.Close()

	if _, err := client.DeleteSchemaRevision(ctx, schemaID, revisionID); err != nil {
		return fmt.Errorf("client.DeleteSchema revision: %w", err)
	}
	fmt.Fprintf(w, "Deleted a schema revision: %s@%s", schemaID, revisionID)
	return nil
}

Java

Before trying this sample, follow the Java setup instructions in Quickstart: Using Client Libraries. For more information, see the Pub/Sub Java API reference documentation.

import com.google.api.gax.rpc.NotFoundException;
import com.google.cloud.pubsub.v1.SchemaServiceClient;
import com.google.pubsub.v1.DeleteSchemaRevisionRequest;
import com.google.pubsub.v1.SchemaName;
import java.io.IOException;

public class DeleteSchemaRevisionExample {

  public static void main(String... args) throws Exception {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "your-project-id";
    String schemaId = "your-schema-id@your-revision-id";

    deleteSchemaRevisionExample(projectId, schemaId);
  }

  public static void deleteSchemaRevisionExample(String projectId, String schemaId)
      throws IOException {
    SchemaName schemaName = SchemaName.of(projectId, schemaId);

    try (SchemaServiceClient schemaServiceClient = SchemaServiceClient.create()) {

      DeleteSchemaRevisionRequest request =
          DeleteSchemaRevisionRequest.newBuilder().setName(schemaName.toString()).build();

      schemaServiceClient.deleteSchemaRevision(request);

      System.out.println("Deleted a schema revision:" + schemaName);

    } catch (NotFoundException e) {
      System.out.println(schemaName + "not found.");
    }
  }
}

Python

Before trying this sample, follow the Python setup instructions in Quickstart: Using Client Libraries. For more information, see the Pub/Sub Python API reference documentation.

from google.api_core.exceptions import NotFound
from google.cloud.pubsub import SchemaServiceClient

# TODO(developer): Replace these variables before running the sample.
# project_id = "your-project-id"
# schema_id = "your-schema-id"
# revision_id = "your-revision-id"

schema_client = SchemaServiceClient()
schema_path = schema_client.schema_path(project_id, schema_id + "@" + revision_id)

try:
    schema_client.delete_schema_revision(request={"name": schema_path})
    print(f"Deleted a schema revision:\n{schema_path}")
except NotFound:
    print(f"{schema_id} not found.")

Node.js

Before trying this sample, follow the Node.js setup instructions in Quickstart: Using Client Libraries. For more information, see the Pub/Sub Node.js API reference documentation.

/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const schemaNameOrId = 'YOUR_SCHEMA_NAME_OR_ID';
// const revisionId = 'YOUR_REVISION_ID';

// Imports the Google Cloud client library
const {PubSub} = require('@google-cloud/pubsub');

// Creates a client; cache this for further use
const pubSubClient = new PubSub();

async function deleteSchemaRevision(schemaNameOrId, revisionId) {
  // Get the fully qualified schema name.
  const schema = pubSubClient.schema(schemaNameOrId);
  const name = await schema.getName();

  // Use the gapic client to delete the schema revision.
  const schemaClient = await pubSubClient.getSchemaClient();
  await schemaClient.deleteSchemaRevision({
    name: `${name}@${revisionId}`,
  });

  console.log(`Schema ${name} revision ${revisionId} deleted.`);
}

Node.js

Before trying this sample, follow the Node.js setup instructions in Quickstart: Using Client Libraries. For more information, see the Pub/Sub Node.js API reference documentation.

/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const schemaNameOrId = 'YOUR_SCHEMA_NAME_OR_ID';
// const revisionId = 'YOUR_REVISION_ID';

// Imports the Google Cloud client library
import {PubSub} from '@google-cloud/pubsub';

// Creates a client; cache this for further use
const pubSubClient = new PubSub();

async function deleteSchemaRevision(
  schemaNameOrId: string,
  revisionId: string
) {
  // Get the fully qualified schema name.
  const schema = pubSubClient.schema(schemaNameOrId);
  const name = await schema.getName();

  // Use the gapic client to delete the schema revision.
  const schemaClient = await pubSubClient.getSchemaClient();
  await schemaClient.deleteSchemaRevision({
    name: `${name}@${revisionId}`,
  });

  console.log(`Schema ${name} revision ${revisionId} deleted.`);
}

What's next

• Delete a schema
• List schemas
• List revisions of a schema
• Subscribe to a topic with a schema