PromQL Tenant Proxy 🦀

A high-performance, lightweight HTTP proxy that extracts tenant information from PromQL labels and converts them into upstream HTTP headers. Built with Rust for sub-millisecond latency and memory safety.

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🚀 Overview

Many multi-tenant time-series databases (like Grafana Mimir, Cortex, or VictoriaMetrics) require a tenant identifier in the HTTP headers (e.g., X-Scope-OrgID). However, many clients only support filtering via PromQL labels.

PromQL Tenant Proxy solves this by:

1. Intercepting the /api/v1/query and /api/v1/query_range requests.
2. Parsing the PromQL into an Abstract Syntax Tree (AST).
3. Extracting a specific label (e.g., environment or tenant).
4. Injecting that value as a header before forwarding the request to the upstream storage.

✨ Features

• True AST Parsing: Uses promql-parser to navigate complex queries, including nested functions, aggregations, and binary expressions.
• Blazing Fast: Leverages Axum and Tokio for non-blocking I/O.
• Minimal Footprint: No garbage collection and efficient memory management, making it ideal for sidecar deployments.
• Safe by Design: Rust's borrow checker prevents common memory-related vulnerabilities and race conditions.