Sylin.Koan.Data.Connector.ElasticSearch

Sylin.Koan.Data.Connector.ElasticSearch

Elasticsearch vector storage for Koan Entities. The application declares one vector space; the connector realizes that plan through Elasticsearch dense_vector, native kNN search, and native metadata pre-filtering.

• Target framework: net10.0
• License: Apache-2.0

Install

dotnet add package Sylin.Koan.Data.Connector.ElasticSearch

Use

builder.Services.AddKoan(koan => koan.Data
    .Source("Search")
    .Vector<Article>(space => space
        .Name("content")
        .Dimensions(1536)
        .Metric(VectorMetric.Cosine)
        .Visibility(VectorVisibility.Session)));

await Vector<Article>.Save("article-1", embedding, new { category = "docs" });

var nearest = await Vector<Article>.Search(
    embedding,
    query => query.Top(5).Where(Filter.Eq("category", "docs")));

The space declaration owns its name, dimensions, metric, model, source, and visibility. Standard source declarations own access and storage lifecycle. Elasticsearch configuration owns only placement, credentials, timeouts, and bounded work limits.

Configuration

{
  "Koan": {
    "Data": {
      "ElasticSearch": {
        "Endpoint": "https://search.example.net:9200",
        "ApiKey": "use-your-secret-provider",
        "TimeoutSeconds": 30,
        "MaxSearchCandidates": 10000
      }
    }
  }
}

HTTP Basic authentication uses Username and Password. ConnectionStrings:ElasticSearch remains an endpoint alternative. Standard named-source routing can select a different endpoint and credentials without changing Entity code. Keep credentials in the platform secret store.

Guarantees

• complete point reads return logical identity, embedding, and neutral metadata;
• Cosine, Euclidean, and unrestricted DotProduct spaces have explicit native mappings and normalized higher-is-closer scores;
• awaited mutations use explicit refresh and are visible to subsequent Session reads;
• Eq, Ne, ranges, In, Nin, Has, HasAny, HasAll, HasNone, Size, and Exists run as native kNN pre-filters; unsupported filters fail closed;
• single and bulk upsert/delete preserve ordered outcomes; bulk atomicity is reported as not guaranteed;
• Managed sources may create storage, External sources validate only, and ReadOnly sources reject mutations before I/O;
• source, partition, container, and row scopes isolate every read and mutation path;
• requests, responses, metadata, batches, candidates, retries, and tie expansion are bounded.

Deliberate limits

• This is a Vector adapter, not a general Elasticsearch Entity adapter.
• Search accuracy is approximate because Elasticsearch uses indexed approximate kNN.
• Eventual visibility, hybrid text search, continuation snapshots, streaming export, and atomic batches are not claimed.
• The adapter generates and validates its write alias and backing index. There is no ordinary index-name, field-name, dimension, metric, refresh, or auto-create option.
• Existing external mappings must carry the Koan contract marker and match the declared space exactly.

Reference

• Technical reference
• Vector runtime