CartDiscount Sync

The module used for importing/syncing CartDiscounts into a commercetools project. It also provides utilities for generating update actions based on the comparison of a CartDiscount against a CartDiscountDraft.

• Usage
• Prerequisites
  • SphereClient
  • Required Fields
  • Reference Resolution
  • Syncing from a commercetools project
  • Syncing from an external resource
  • SyncOptions
  • errorCallback
  • warningCallback
  • beforeUpdateCallback
  • beforeCreateCallback
  • batchSize
  • cacheSize
• Running the sync
  • More examples of how to use the sync
• Build all update actions
• Build particular update action(s)
• Caveats

Usage

Prerequisites

SphereClient

Use the ClientConfigurationUtils which apply the best practices for SphereClient creation. If you have custom requirements for the sphere client creation, have a look into the Important Usage Tips.

final SphereClientConfig clientConfig = SphereClientConfig.of("project-key", "client-id", "client-secret");

final SphereClient sphereClient = ClientConfigurationUtils.createClient(clientConfig);

Required Fields

The following fields are required to be set in, otherwise, they won't be matched by sync:

Draft	Required Fields	Note
CartDiscountDraft.	key	Also, the cart discounts in the target project are expected to have the key fields set.

Reference Resolution

In commercetools, a reference can be created by providing the key instead of the ID with the type ResourceIdentifier. When the reference key is provided with a ResourceIdentifier, the sync will resolve the resource with the given key and use the ID of the found resource to create or update a reference. Therefore, in order to resolve the actual ids of those references in the sync process, ResourceIdentifiers with their keys have to be supplied.

Reference Field	Type
custom.type	ResourceIdentifier to a Type

Note that a reference without the key field will be considered as an existing resource on the target commercetools project and the library will issue an update/create an API request without reference resolution.

Syncing from a commercetools project

When syncing from a source commercetools project, you can use toCartDiscountDrafts method that transforms(resolves by querying and caching key-id pairs) and maps from a CartDiscount to CartDiscountDraft using cache in order to make them ready for reference resolution by the sync, for example:

// Build a CartDiscountQuery for fetching cart discounts from a source CTP project without any references expanded for the sync:
final CartDiscountQuery cartDiscountQuery = CartDiscountQuery.of();

// Query all cart discounts (NOTE this is just for example, please adjust your logic)
final List<CartDiscount> cartDiscounts =
    CtpQueryUtils
        .queryAll(sphereClient, cartDiscountQuery, Function.identity())
        .thenApply(fetchedResources -> fetchedResources
            .stream()
            .flatMap(List::stream)
            .collect(Collectors.toList()))
        .toCompletableFuture()
        .join();

In order to transform and map the CartDiscount to CartDiscountDraft, Utils method toCartDiscountDrafts requires sphereClient, implementation of ReferenceIdToKeyCache and cartDiscounts as parameters. For cache implementation, You can use your own cache implementation or use the class in the library - which implements the cache using caffeine library with an LRU (Least Recently Used) based cache eviction strategyCaffeineReferenceIdToKeyCacheImpl. Example as shown below:

//Implement the cache using library class.
final ReferenceIdToKeyCache referenceIdToKeyCache = new CaffeineReferenceIdToKeyCacheImpl();

//For every reference fetch its key using id, cache it and map from CartDiscount to CartDiscountDraft. With help of the cache same reference keys can be reused.
CompletableFuture<List<CartDiscountDraft>> cartDiscountDrafts = CartDiscountTransformUtils.toCartDiscountDrafts(client, referenceIdToKeyCache, cartDiscounts);

Syncing from an external resource

• When syncing from an external resource, ResourceIdentifiers with their keys have to be supplied as following example:

final CartDiscountDraft cartDiscountDraft = CartDiscountDraftBuilder
    .of("cartPredicate",
        LocalizedString.ofEnglish("foo"),
        true,
        "0.1",
        ShippingCostTarget.of(),
        CartDiscountValue.ofAbsolute(MoneyImpl.of(10, DefaultCurrencyUnits.EUR)))
    .key("cart-discount-key")
    .custom(CustomFieldsDraft.ofTypeKeyAndJson("type-key", emptyMap())) // note that custom type provided with key 
    .build(); 

SyncOptions

After the sphereClient is set up, a CartDiscountSyncOptions should be built as follows:

// instantiating a CartDiscountSyncOptions
final CartDiscountSyncOptions cartDiscountSyncOptions = CartDiscountSyncOptionsBuilder.of(sphereClient).build();

SyncOptions is an object which provides a place for users to add certain configurations to customize the sync process. Available configurations:

errorCallback

A callback that is called whenever an error event occurs during the sync process. Each resource executes its own error-callback. When the sync process of a particular resource runs successfully, it is not triggered. It contains the following context about the error-event:

• sync exception
• cart discount draft from the source
• cart discount of the target project (only provided if an existing cart discount could be found)
• the update-actions, which failed (only provided if an existing cart discount could be found)

 final Logger logger = LoggerFactory.getLogger(CartDiscountSync.class);
 final CartDiscountSyncOptions cartDiscountSyncOptions = CartDiscountSyncOptionsBuilder
         .of(sphereClient)
         .errorCallback((syncException, draft, cartDiscount, updateActions) -> 
            logger.error(new SyncException("My customized message"), syncException)).build();

warningCallback

A callback is called whenever a warning event occurs during the sync process. Each resource executes its own warning-callback. When the sync process of a particular resource runs successfully, it is not triggered. It contains the following context about the warning message:

• sync exception
• cart discount draft from the source
• cart discount of the target project (only provided if an existing cart discount could be found)

 final Logger logger = LoggerFactory.getLogger(CartDiscountSync.class);
 final CartDiscountSyncOptions cartDiscountSyncOptions = CartDiscountSyncOptionsBuilder
         .of(sphereClient)
         .warningCallback((syncException, draft, cartDiscount, updateActions) -> 
            logger.warn(new SyncException("My customized message"), syncException)).build();

beforeUpdateCallback

During the sync process, if a target cart discount and a cart discount draft are matched, this callback can be used to intercept the update request just before it is sent to the commercetools platform. This allows the user to modify update actions array with custom actions or discard unwanted actions. The callback provides the following information :

• cart discount draft from the source
• cart discount from the target project
• update actions that were calculated after comparing both

final TriFunction<
        List<UpdateAction<CartDiscount>>, CartDiscountDraft, CartDiscount, List<UpdateAction<CartDiscount>>> 
            beforeUpdateCartDiscountCallback =
            (updateActions, newCartDiscountDraft, oldCartDiscount) ->  updateActions.stream()
                    .filter(updateAction -> !(updateAction instanceof ChangeCartPredicate))
                    .collect(Collectors.toList());

final CartDiscountSyncOptions cartDiscountSyncOptions = 
        CartDiscountSyncOptionsBuilder.of(sphereClient).beforeUpdateCallback(beforeUpdateCartDiscountCallback).build();

beforeCreateCallback

During the sync process, if a cart discount draft should be created, this callback can be used to intercept the create request just before it is sent to the commercetools platform. It contains the following information :

• cart discount draft that should be created

Please refer to example in product sync document.

batchSize

A number that could be used to set the batch size with which cart discounts are fetched and processed, as cart discounts are obtained from the target project on the commercetools platform in batches for better performance. The algorithm accumulates up to batchSize resources from the input list, then fetches the corresponding cart discounts from the target project on the commecetools platform in a single request. Playing with this option can slightly improve or reduce processing speed. If it is not set, the default batch size is 50 for cart discount sync.

final CartDiscountSyncOptions cartDiscountSyncOptions = 
         CartDiscountSyncOptionsBuilder.of(sphereClient).batchSize(30).build();

cacheSize

In the service classes of the commercetools-sync-java library, we have implemented an in-memory LRU cache to store a map used for the reference resolution of the library. The cache reduces the reference resolution based calls to the commercetools API as the required fields of a resource will be fetched only one time. These cached fields then might be used by another resource referencing the already resolved resource instead of fetching from commercetools API. It turns out, having the in-memory LRU cache will improve the overall performance of the sync library and commercetools API. which will improve the overall performance of the sync and commercetools API.

Playing with this option can change the memory usage of the library. If it is not set, the default cache size is 10.000 for cart discount sync.

final CartDiscountSyncOptions cartDiscountSyncOptions = 
         CartDiscountSyncOptionsBuilder.of(sphereClient).cacheSize(5000).build(); 

Running the sync

After all the aforementioned points in the previous section have been fulfilled, to run the sync:

// instantiating a cart discount sync
final CartDiscountSync cartDiscountSync = new CartDiscountSync(cartDiscountSyncOptions);

// execute the sync on your list of cart discounts
CompletionStage<CartDiscountSyncStatistics> syncStatisticsStage = cartDiscountSync.sync(cartDiscountDrafts);

The result of completing the syncStatisticsStage in the previous code snippet contains a CartDiscountSyncStatistics which contains all the stats of the sync process; which includes a report message, the total number of updated, created, failed, processed cart discounts and the processing time of the last sync batch in different time units and in a human-readable format.

final CartDiscountSyncStatistics stats = syncStatisticsStage.toCompletebleFuture().join();
stats.getReportMessage();
/*"Summary: 100 cart discounts were processed in total (11 created, 87 updated, 2 failed to sync)."*/

Note The statistics object contains the processing time of the last batch only. This is due to two reasons:

1. The sync processing time should not take into account the time between supplying batches to the sync.
2. It is not known by the sync which batch is going to be the last one supplied.

More examples of how to use the sync

1. Sync from another CTP project as a source.
2. Sync from an external source.

Make sure to read the Important Usage Tips for optimal performance.

Build all update actions

A utility method provided by the library to compare a CartDiscount with a new CartDiscountDraft and results in a list of cart discount update actions.

List<UpdateAction<CartDiscount>> updateActions = CartDiscountSyncUtils.buildActions(cartDiscount, cartDiscountDraft, cartDiscountSyncOptions);

Build particular update action(s)

Utility methods provided by the library to compare the specific fields of a CartDiscount and a new CartDiscountDraft, and in turn builds the update action. One example is the buildChangeNameUpdateAction which compares names:

Optional<UpdateAction<CartDiscount>> updateAction = CartDiscountUpdateActionUtils.buildChangeNameAction(oldCartDiscount, cartDiscountDraft);

More examples of those utils for different cart discounts can be found here.

Caveats

1. Syncing cart discounts with a CartDiscountValue of type giftLineItem is not supported yet. #411.