Migrating to google-cloud-vision 1.0

The 1.0 release of the google-cloud-vision client is a significant upgrade based on a next-gen code generator, and includes substantial interface changes. Existing code written for earlier versions of this library will likely require updates to use this version. This document describes the changes that have been made, and what you need to do to update your usage.

To summarize:

• The library has been broken out into multiple libraries. The new gems google-cloud-vision-v1 and google-cloud-vision-v1p3beta1 contain the actual client classes for versions V1 and V1p3beta1 of the Vision service, and the gem google-cloud-vision now simply provides a convenience wrapper. See Library Structure for more info.
• The library uses a new configuration mechanism giving you closer control over endpoint address, network timeouts, and retry. See Client Configuration for more info. Furthermore, when creating a client object, you can customize its configuration in a block rather than passing arguments to the constructor. See Creating Clients for more info.
• Previously, positional arguments were used to indicate required arguments. Now, all method arguments are keyword arguments, with documentation that specifies whether they are required or optional. Additionally, you can pass a proto request object instead of separate arguments. See Passing Arguments for more info.
• Previously, some client classes included class methods for constructing resource paths. These paths are now instance methods on the client objects, and are also available in a separate paths module. See Resource Path Helpers for more info.
• Previously, the client included a number of high-level convenience methods, such as face_detection, for detecting particular types of features. These methods are still present, but a few of the parameter types (relating to call configuration) have changed. See High Level Detection Methods for more info.
• Previously, clients reported RPC errors by raising instances of Google::Gax::GaxError and its subclasses. Now, RPC exceptions are of type Google::Cloud::Error and its subclasses. See Handling Errors for more info.
• Some classes have moved into different namespaces. See Class Namespaces for more info.

Library Structure

Older 0.x releases of the google-cloud-vision gem were all-in-one gems that included potentially multiple clients for multiple versions of the Vision service. Factory methods such as Google::Cloud::Vision::ImageAnnotator.new would return you instances of client classes such as Google::Cloud::Vision::V1::ImageAnnotatorClient or Google::Cloud::Vision::V1p3beta1::ImageAnnotatorClient, depending on which version of the API requested. These classes were all defined in the same gem.

With the 1.0 release, the google-cloud-vision gem still provides factory methods for obtaining clients. (The method signatures will have changed. See Creating Clients for details.) However, the actual client classes have been moved into separate gems, one per service version. The Google::Cloud::Vision::V1::ImageAnnotator::Client class, along with its helpers and data types, is now part of the google-cloud-vision-v1 gem. Similarly, the Google::Cloud::Vision::V1p3beta1::ImageAnnotator::Client class is part of the google-cloud-vision-v1p3beta1 gem.

For normal usage, you can continue to install the google-cloud-vision gem (which will bring in the versioned client gems as dependencies) and continue to use factory methods to create clients. However, you may alternatively choose to install only one of the versioned gems. For example, if you know you will only use V1 of the service, you can install google-cloud-vision-v1 by itself, and construct instances of the Google::Cloud::Vision::V1::ImageAnnotator::Client client class directly.

Client Configuration

In older releases, if you wanted to customize performance parameters or low-level behavior of the client (such as credentials, timeouts, or instrumentation), you would pass a variety of keyword arguments to the client constructor. It was also extremely difficult to customize the default settings.

With the 1.0 release, a configuration interface provides control over these parameters, including defaults for all instances of a client, and settings for each specific client instance. For example, to set default credentials and timeout for all Vision V1 image annotator clients:

Google::Cloud::Vision::V1::ImageAnnotator::Client.configure do |config|
  config.credentials = "/path/to/credentials.json"
  config.timeout = 10.0
end

Individual RPCs can also be configured independently. For example, to set the timeout for the batch_annotate_images call:

Google::Cloud::Vision::V1::ImageAnnotator::Client.configure do |config|
  config.rpcs.batch_annotate_images.timeout = 20.0
end

Defaults for certain configurations can be set for all Vision versions and services globally:

Google::Cloud::Vision.configure do |config|
  config.credentials = "/path/to/credentials.json"
  config.timeout = 10.0
end

Finally, you can override the configuration for each client instance. See the next section on Creating Clients for details.

Creating Clients

In older releases, to create a client object, you would use the new method of modules under Google::Cloud::Vision. For example, you might call Google::Cloud::Vision::ImageAnnotator.new. Keyword arguments were available to select a service version and to configure parameters such as credentials and timeouts.

With the 1.0 release, use named class methods of Google::Cloud::Vision to create a client object. For example, Google::Cloud::Vision.image_annotator. You may select a service version using the :version keyword argument. However, other configuration parameters should be set in a configuration block when you create the client.

Old:

client = Google::Cloud::Vision::ImageAnnotator.new credentials: "/path/to/credentials.json"

New:

client = Google::Cloud::Vision.image_annotator do |config|
  config.credentials = "/path/to/credentials.json"
end

The configuration block is optional. If you do not provide it, or you do not set some configuration parameters, then the default configuration is used. See Client Configuration.

Passing Arguments

In older releases, required arguments would be passed as positional method arguments, while most optional arguments would be passed as keyword arguments.

With the 1.0 release, all RPC arguments are passed as keyword arguments, regardless of whether they are required or optional. For example:

Old:

client = Google::Cloud::Vision::ImageAnnotator.new

requests = my_create_requests

# requests is a positional argument
response = client.batch_annotate_images requests

New:

client = Google::Cloud::Vision.image_annotator

requests = my_create_requests

# requests is a keyword argument
response = client.batch_annotate_images requests: requests

In the 1.0 release, it is also possible to pass a request object, either as a hash or as a protocol buffer.

New:

client = Google::Cloud::Vision.image_annotator

request_object = Google::Cloud::Vision::V1::BatchAnnotateImagesRequest.new(
  requests: my_create_requests
)

# Pass a request object as a positional argument:
response = client.batch_annotate_images request_object

Finally, in older releases, to provide call options, you would pass a Google::Gax::CallOptions object with the :options keyword argument. In the 1.0 release, pass call options using a second set of keyword arguments.

Old:

client = Google::Cloud::Vision::ImageAnnotator.new

requests = my_create_requests

options = Google::Gax::CallOptions.new timeout: 10.0

response = client.batch_annotate_images requests, options: options

New:

client = Google::Cloud::Vision.image_annotator

requests = my_create_requests

# Use a hash to wrap the normal call arguments (or pass a request object), and
# then add further keyword arguments for the call options.
response = client.batch_annotate_images({ requests: requests }, timeout: 10.0)

Resource Path Helpers

The client library includes helper methods for generating the resource path strings passed to many calls. These helpers have changed in two ways:

• In older releases, they are class methods on the client class. In the 1.0 release, they are instance methods on the client. They are also available on a separate paths module that you can include elsewhere for convenience.
• In older releases, arguments to a resource path helper are passed as positional arguments. In the 1.0 release, they are passed as named keyword arguments.

Following is an example involving using a resource path helper.

Old:

client = Google::Cloud::Vision::ProductSearch.new

# Call the helper on the client class
location = Google::Cloud::Vision::V1::ProductSearchClient.location_path(
  "my-project", "my-location"
)

product = my_build_product
response = client.create_product location, product

New:

client = Google::Cloud::Vision.product_search

# Call the helper on the client instance, and use keyword arguments
location = client.location_path project: "my-project", location: "my-location"

product = my_build_product
response = client.create_product parent: location, product: product

In the 1.0 client, you can also use the paths module as a convenience module.

New:

# Bring the path helper methods into the current class
include Google::Cloud::Vision::V1::ProductSearch::Paths

def foo
  client = Google::Cloud::Vision.product_search

  # Call the included helper method
  location = location_path project: "my-project", location: "my-location"

  product = my_build_product
  response = client.create_product parent: location, product: product

  # Do something with response...
end

High Level Detection Methods

The client library includes some high-level convenience methods, with names such as face_detection, for detecting certain types of features. These methods are still present, but a few of the argument types have changed.

• The options keyword argument is used to pass call options such as timeout and retry. Older versions of the library took an object of type Google::Gax::CallOptions. Version 1.0 takes an object of type Gapic::CallOptions, which is defined in the gapic-common gem. Note that you can also pass a hash with the same keys that the older library accepted.
• If async is set to true, older versions of the library returned an object of type Google::Gax::Operation. Version 1.0 returns an object of type Gapic::Operation, which is defined in the gapic-common gem. Most methods on this object are the same as the older object.

Handling Errors

The client reports standard gRPC error codes by raising exceptions. In older releases, these exceptions were located in the Google::Gax namespace and were subclasses of the Google::Gax::GaxError base exception class, defined in the google-gax gem. However, these classes were different from the standard exceptions (subclasses of Google::Cloud::Error) thrown by other client libraries such as google-cloud-storage.

The 1.0 client library now uses the Google::Cloud::Error exception hierarchy, for consistency across all the Google Cloud client libraries. In general, these exceptions have the same name as their counterparts from older releases, but are located in the Google::Cloud namespace rather than the Google::Gax namespace.

Old:

client = Google::Cloud::Vision::ImageAnnotator.new

requests = my_create_requests

begin
  response = client.batch_annotate_images requests
rescue Google::Gax::Error => e
  # Handle exceptions that subclass Google::Gax::Error
end

New:

client = Google::Cloud::Vision.image_annotator

requests = my_create_requests

begin
  response = client.batch_annotate_images requests: requests
rescue Google::Cloud::Error => e
  # Handle exceptions that subclass Google::Cloud::Error
end

Class Namespaces

In older releases, the client object was of classes with names like: Google::Cloud::Vision::V1::ProductSearchClient. In the 1.0 release, the client object is of a different class: Google::Cloud::Vision::V1::ProductSearch::Client. Note that most users will use the factory methods such as Google::Cloud::Vision.product_search to create instances of the client object, so you may not need to reference the actual class directly. See Creating Clients.

In older releases, the credentials object was of class Google::Cloud::Vision::V1::Credentials. In the 1.0 release, each service has its own credentials class, e.g. Google::Cloud::Vision::V1::ProductSearch::Credentials. Again, most users will not need to reference this class directly. See Client Configuration.