orion-search/opensearch

Orion’s engine adapter for OpenSearch 2.19 and 3.x, on the official opensearch-project/opensearch-php client (one client major speaks to both server lines).

use OpenSearch\GuzzleClientFactory;
use Orion\OpenSearch\OpenSearchEngine;
use Orion\Registry\EngineRegistry;

$engines = new EngineRegistry(opensearch: new OpenSearchEngine((new GuzzleClientFactory())->create(['base_uri' => $url])));
// or, from a URL: OpenSearchEngine::connect($url)

• Mappings are dynamic: strict: a document carrying an undeclared field fails alone instead of growing the mapping.
• Writes and deletes are externally versioned with the outbox offset; a version conflict is a stale write, never a failure, so replayed and live writes converge.
• integer maps to long, float to double; any other native type inspects as unknown and fails a plan closed.
• A vector is a knn_vector on the Lucene engine (HNSW, the metric as its space type) and turns index.knn on for the index; the neutral vector query is the k-NN plugin’s knn query, filters applied while the neighbours are gathered. Adding a vector field to an index created without one needs a reindex.
• IndexSchema::native('opensearch', ['settings' => [...], 'mappings' => [...]]) merges over the generated body.
• raw() takes callable(): array returning a search body; scope filters are ANDed into it and into every knn query; search pipelines, aggregations, suggesters and derived fields are refused under a scope.
• Native hybrid search needs a search pipeline whose normalisation is not Orion’s deterministic fusion, so HybridFusion is reported false and core fuses.

Proven by Orion\Testing\EngineConformanceTestCase against OpenSearch 3.9 and 2.19.