elastic-mock

elastic-mock is a lightweight, high-performance, in-memory Elasticsearch mock server designed for integration testing. It emulates the Elasticsearch 8.x REST API, allowing you to test search-driven applications without the overhead of a full Elasticsearch cluster.

Developed and maintained by Gemini and Qwen.

Implementation Status: [COMPLETE]

All core phases of the roadmap have been implemented and verified with a comprehensive suite of integration tests.

• ✅ Indices Management: Creation, deletion, and mapping retrieval.
• ✅ Document CRUD: Indexing, partial updates, and deletion.
• ✅ Search & Query DSL: Full-text match, exact term filtering, and bool logic.
• ✅ Aggregation Engine: terms, avg, min, max, and sum support.
• ✅ Bulk API: High-volume ingestion via NDJSON.
• ✅ CAT APIs: Human-readable stats for indices, nodes, and health.
• ✅ Data Streams: Native support with backing index management and rollover.
• ✅ Machine Learning & Graph: Support for data frame analytics, snapshot upgrades, and graph exploration.
• ✅ Logging: Structured API logging using Winston.

Installation

npm install -g elastic-mock

Usage

Start the Server

Start the mock server on the default port (19200):

elastic-mock

Custom Port

Specify a custom port using the --port flag:

elastic-mock --port 9201

Health Check

Verify the server is running:

curl http://localhost:19200/_cluster/health

Features

• Elasticsearch 8.x Compatible: Follows the 8.x REST API specification, including mandatory headers.
• In-Memory Storage: Uses a central Store with JavaScript Map objects. No disk persistence.
• High Performance: Powered by FlexSearch for fast full-text indexing.
• Comprehensive Logging: Detailed request/response logging via winston.
• Developer Friendly: Includes prettier for formatting and a strict CI pipeline.

Testing

The project is verified against both internal test suites and official Elasticsearch client tests.

• Internal Tests: 30 integration and unit tests passing.
• External Tests: Verified using the elasticsearch-clients-tests suite.
  • Status: 221 passed, 0 failed.

Development

Detailed design, architecture, and implementation information can be found in the docs/README.md.

Pre-commit Checklist

As defined in AGENTS.md, ensure quality with:

1. npm run format
2. npm run build
3. npm run test (Unit & Integration)
4. npm run test:external (Official client tests)

License

ISC