Body Size Limit With Extraction

Combines body_limits.max_request_bytes with json_body_field to enforce a global body ceiling while still performing body-based routing

Category: Practical
Task: Combines body_limits.max_request_bytes with json_body_field to enforce a global body ceiling while still performing body-based routing

Prerequisites: The product runtime and any backend services referenced by this configuration.

This configuration comes from the selected release. The example has not been run here; external services are not bundled.

Download the source file.

# Body Size Limit with Field Extraction
#
# Combines body_limits.max_request_bytes with json_body_field to
# enforce a global body ceiling while still performing
# body-based routing. Requests exceeding the limit receive
# 413 (Payload Too Large) before any extraction occurs.
#
# The global limit caps the StreamBuffer accumulation, so
# even if the filter declares no per-filter limit, the
# pipeline enforces the ceiling.
#
# Usage:
#   cargo run -p praxis-proxy -- -c examples/configs/payload-processing/body-size-limit-with-extraction.yaml
#
#   # Small body: extracted and routed normally
#   curl -X POST http://localhost:8080/v1/chat \
#     -H "Content-Type: application/json" \
#     -d '{"model": "model-alpha-1", "prompt": "hello"}'
#
#   # Oversized body: rejected with 413
#   curl -X POST http://localhost:8080/v1/chat \
#     -H "Content-Type: application/json" \
#     -d @large-payload.json

listeners:
  - name: gateway
    address: "0.0.0.0:8080" # dev value; binds all interfaces
    filter_chains:
      - extract-model
      - routing

filter_chains:
  - name: extract-model
    filters:
      - filter: json_body_field
        field: model
        header: X-Model

  - name: routing
    filters:
      - filter: router
        routes:
          - path_prefix: "/"
            cluster: backend
      - filter: load_balancer
        clusters:
          - name: backend
            endpoints:
              - "127.0.0.1:3000"

# 1 KB ceiling: any request body over 1024 bytes is
# rejected with 413 before field extraction runs.
body_limits:
  max_request_bytes: 1024

insecure_options:
  allow_private_endpoints: true # example proxies to local backends