Lupyne is a search engine based on PyLucene, the Python extension for accessing Java Lucene. Lucene is a relatively low-level toolkit, and PyLucene wraps it through automatic code generation. So although Java idioms are translated to Python idioms where possible, the resulting interface is far from Pythonic. See ./docs/examples.ipynb for comparisons with the Lucene API.

Lupyne also provides a RESTful JSON search server, based on CherryPy. Note Solr and Elasticsearch are popular options for Lucene-based search, if no further (Python) customization is needed. So while the server is suitable for production usage, its primary motivation is to be an extensible example.

Not having to initially choose between an embedded library and a server not only provides greater flexibility, it can provide better performance, e.g., batch indexing offline and remote searching live. Additionally only lightweight wrappers with extended behavior are used wherever possible, so falling back to using PyLucene directly is always an option, but should never be necessary for performance.

Usage

PyLucene requires initializing the VM.

import lucene

lucene.initVM()

Indexes are accessed through an IndexSearcher (read-only), IndexWriter, or the combined Indexer.

from lupyne import engine

searcher = engine.IndexSearcher('index/path')
hits = searcher.search('text:query')

Run the server.

% python -m lupyne.server

Read the documentation.

Installation

% pip install lupyne[server]

PyLucene is not pip installable.

• Install instructions
• Docker image: docker pull coady/pylucene
• Homebrew formula: brew install coady/tap/pylucene

Dependencies

• PyLucene >=8
• cherrypy >=11 (if server option)

Tests

100% branch coverage.

% pytest [--cov]

Roadmap

The server interface is being simplified in anticipation of switching web frameworks, to support OpenAPI and GraphQL.

Changes

dev

• Python >=3.6 required
• Simplified server command-line options

2.4

• PyLucene >=8 required
• Hit.keys renamed to Hit.sortkeys

2.3

• PyLucene >=7.7 required
• PyLucene 8 supported

2.2

• PyLucene 7.6 supported

2.1

• PyLucene >=7 required

2.0

• PyLucene >=6 required
• Python 3 support
• client moved to external package

1.9

• Python 2.6 dropped
• PyLucene 4.8 and 4.9 dropped
• IndexWriter implements context manager
• Server DocValues updated via patch method
• Spatial tile search optimized

1.8

• PyLucene 4.10 supported
• PyLucene 4.6 and 4.7 dropped
• Comparator iteration optimized
• Support for string based FieldCacheRangeFilters