Monitoring

Whoosh-NG ships with hooks for observability and a Prometheus plugin for production use.

Built-in Metrics

from whoosh.middleware import MetricsMiddleware, MiddlewareChain
from whoosh.middleware.integration import apply_middleware_to_writer, apply_middleware_to_searcher

chain = MiddlewareChain([MetricsMiddleware()])
writer = apply_middleware_to_writer(ix.writer(), chain.middlewares)
searcher = apply_middleware_to_searcher(ix.searcher(), chain.middlewares)

metrics = chain.get_metrics()
print(metrics)

Prometheus

pip install whoosh-ng[metrics]

Metric	Type	Description
whoosh_documents_indexed_total	Counter	Total documents indexed
whoosh_searches_executed_total	Counter	Total searches executed
whoosh_indexing_duration_seconds	Histogram	Indexing latency
whoosh_search_duration_seconds	Histogram	Search latency
whoosh_index_size_bytes	Gauge	Current index size

Best practices

1. Add MetricsMiddleware early in your base chain.
2. Expose /metrics in production.
3. Use /health for load balancer health checks.
4. Emit DocumentIndexed and SearchExecuted events.