OpenSearch Sink

The Wallaby.Sinks.OpenSearch package keeps OpenSearch indexes continuously in sync with your Postgres tables. Changes are delivered through the _bulk API: upserts are indexed with _id set to a stable document id (so updates are idempotent) and deletions remove by that same id. It works with self-managed OpenSearch and Amazon OpenSearch Service.

Install

dotnet add package Wallaby.Sinks.OpenSearch

Register

cdc.AddOpenSearchSink("search", s =>
{
    s.Endpoint = "https://localhost:9200";
    s.Username = "wallaby";       // basic auth; omit for an unsecured cluster
    s.Password = password;
    s.DefaultIndex = "documents"; // optional fallback when a mapping has no destination
});

Then attach the entities it indexes, using the destination as the index name (index names must be lowercase):

cdc.AddOpenSearchSink("search", s => { /* ... */ })
   .WithMappings(sink => sink
       .Map<Product>()
       .ToDestination("products")
       .UsingTransform(/* ... */));

Options

Option	Default	Purpose
Endpoint	(required)	OpenSearch base URL.
Username / Password	null	Basic auth; null for unsecured.
ConfigureConnection	null	Full override for the client's connection settings (see below).
DefaultIndex	null	Index used when a routed record has no destination.
MaxActionsPerRequest	500	Actions per _bulk request; larger batches are split into sequential requests, preserving commit order.
TimeoutMs	30000	Per-request timeout.
Refresh	false	When true, bulk requests use refresh=wait_for so documents are searchable before the batch is acknowledged.
SerializerOptions	null	Serializer for document values beyond the natively written scalar types (required for such values on NativeAOT hosts).

Indexes

The sink does not create or configure indexes: an index auto-creates on first write with dynamic mapping (provided the cluster's action.auto_create_index setting allows it, as it does by default). For explicit settings or mappings (analyzers, knn_vector fields, shard counts, …), create the index up front — via Dev Tools, your infrastructure tooling, or a deployment script. In-sink index bootstrapping is planned.

Authentication

Username/Password cover basic auth. Everything else — AWS SigV4, client certificates, connection pools, proxies — is configured by taking over construction of the client's connection settings with ConfigureConnection:

// Amazon OpenSearch Service, signed with the host's AWS credentials
// (requires the OpenSearch.Net.Auth.AwsSigV4 package):
cdc.AddOpenSearchSink("search", s =>
{
    s.Endpoint = "https://my-domain.eu-west-1.es.amazonaws.com";
    s.ConfigureConnection = uri => new ConnectionSettings(
        new SingleNodeConnectionPool(uri), new AwsSigV4HttpConnection(RegionEndpoint.EUWest1));
});

When ConfigureConnection is set, Username/Password are ignored — configure all authentication on the returned settings.

Delivery semantics

Delivery is at-least-once: a batch may be re-sent after a transient failure, and every action is idempotent by _id, so replays converge to the same documents. Batches are chunked into sequential _bulk requests so commit order is preserved.

Failures are classified per response and per bulk item:

• Throttling and server errors (408/429/5xx, connection failures, timeouts) are retryable — the dispatcher backs off and re-sends.
• Request or item rejections (e.g. mapper_parsing_exception from a mapping conflict) are permanent — they indicate a transform/configuration bug, so the pipeline halts rather than silently dropping documents.
• Deleting an already-absent document reports 404 per item; the sink treats that as success.

By default documents become searchable on the index's refresh interval (typically 1s) after the batch is acknowledged; set Refresh = true to make each batch searchable before it is acknowledged, at an indexing-throughput cost.