Connector sync rules

Use connector sync rules to help control which documents are synced between the third-party data source and Elasticsearch. Define sync rules in the Kibana UI for each connector index, under the Sync rules tab for the index.

Sync rules apply to native connectors and connector clients.

Sync rules are a beta feature. Beta features are subject to change and are not covered by the support SLA of general release (GA) features. Elastic plans to promote this feature to GA in a future release.

In Elastic versions 8.8.0 and later all connectors have support for basic sync rules.

Some connectors support advanced sync rules. Learn more in the individual connector’s reference documentation.

There are two types of sync rule:

Before discussing sync rules, it’s important to establish a basic understanding of data filtering concepts. The following diagram shows that data filtering can occur in several different processes/locations.

In this documentation we will focus on remote and integration filtering. Sync rules can be used to modify both of these.

Data might be filtered at its source. We call this remote filtering, as the filtering process is external to Elastic.

Integration filtering acts as a bridge between the original data source and Elasticsearch. Filtering that takes place in the Enterprise Search connectors is an example of integration filtering.

Finally, Elasticsearch can filter data right before persistence using ingest pipelines. We will not focus on ingest pipeline filtering in this guide.

In most cases, your data lake will contain far more data than you want to expose to end users. For example, you may want to search a product catalog, but not include vendor contact information, even if the two are co-located for business purposes.

The optimal time to filter data is early in the data pipeline. There are two main reasons:

In a perfect world, all filtering would be done as remote filtering.

In practice, however, this is not always possible. Some sources do not allow robust remote filtering. Others do, but require special setup (building indexes on specific fields, tweaking settings, etc.) that may require attention from other stakeholders in your organization.

With this in mind, sync rules were designed to modify both remote filtering and integration filtering. Your goal should be to do as much remote filtering as possible, but integration is a perfectly viable fall-back. By definition, remote filtering is applied before the data is obtained from a third-party source. Integration filtering is applied after the data is obtained from a third-party source, but before it is ingested into the Elasticsearch index.

Each basic sync rules can be one of two "policies": include and exclude. Include rules are used to include the documents that "match" the specified condition. Exclude rules are used to exclude the documents that "match" the specified condition.

A "match" is determined based on a condition defined by a combination of "field", "rule", and "value".

The Field column should be used to define which field on a given document should be considered.

The following rules are available in the Rule column:

Finally, the Value column is dependent on:

For example, if a value of [A-Z]{2} might make sense for a regex rule, but much less so for a > rule. Similarly, you probably wouldn’t have a value of espresso when operating on an ip_address field, but perhaps you would for a beverage field.

Exclude all documents that have an ID field with the value greater than 1000.

Exclude all documents that have a state field that matches a specified regex.

The following diagrams illustrate the concept of pagination. A huge data set may not fit into a connector instance’s memory. Splitting data into smaller chunks reduces the risk of out-of-memory errors.

This diagram illustrates an entire dataset being extracted at once:

By comparison, this diagram illustrates a paginated dataset:

Advanced sync rules are only used in remote filtering. You can think of advanced sync rules as a language-agnostic way to represent queries to the data source. Therefore, these rules are highly source-specific.

Each connector supporting advanced sync rules provides its own DSL to specify rules. Refer to the documentation for each connector for details.

You can also use basic sync rules and advanced sync rules together to filter a data set.

The following diagram provides an overview of the order in which advanced sync rules, basic sync rules, and pipeline filtering, are applied to your documents:

In the following example we want to filter a data set containing apartments to only contain apartments with specific properties. We’ll use basic and advanced sync rules throughout the example.

A sample apartment looks like this in the .json format:

    {
        "id": 1234,
        "bedrooms": 3,
        "price": 1500,
        "address": {
            "street": "Street 123",
            "government_area": "Area",
            "country_information": {
                "country_code": "PT",
                "country": "Portugal"
    }
  }
}

The target data set should fulfill the following conditions:

The first 3 conditions can be handled by basic sync rules, but we’ll need to use advanced sync rules for number 4.

To create a new basic sync rule, navigate to the Sync Rules tab and select Draft new sync rules:

Afterwards you need to press the Save and validate draft button to validate these rules. Note that when saved the rules will be in draft state. They won’t be executed in the next sync unless they are applied.

After a successful validation you can apply your rules so they’ll be executed in the next sync.

These following conditions can be covered by basic sync rules:

You want to only include apartments which are located in Portugal or Spain. We need to use advanced sync rules here, because we’re dealing with deeply nested objects.

Let’s assume that the apartment data is stored inside a MongoDB instance. For MongoDB we support aggregation pipelines in our advanced sync rules among other things. An aggregation pipeline to only select properties located in Portugal or Spain looks like this:

    [
      {
        "$match": {
             "$or": [
                    {
                      "address.country_information.country": "Portugal"
                    },
                    {
                      "address.country_information.country": "Spain"
                    }
                  ]
                }
      }
    ]

To create these advanced sync rules navigate to the sync rules creation dialog and select the Advanced rules tab. You can now paste your aggregation pipeline into the input field under aggregate.pipeline:

Once validated, apply these rules. The following screenshot shows the applied sync rules, which will be executed in the next sync:

After a successful sync you can expand the sync details to see which rules were applied: