This repository is a small Rust reverse proxy server (Axum + Reqwest). Use this file as the primary guidance for automated agents working here.

• Keep changes minimal and idiomatic to this codebase.
• Prefer explicit, readable code over cleverness.
• Avoid adding dependencies unless necessary; keep Cargo.toml lean.

• No Cursor rules found in .cursor/rules/ or .cursorrules.
• No Copilot rules found in .github/copilot-instructions.md.

If new rules are added later, incorporate them here.

Common commands (run from repo root):

# Build (debug)
cargo build

# Build (release)
cargo build --release

# Run (needs config file)
cargo run -- -c /path/to/config.toml

# Format (Rust standard formatting)
cargo fmt

# Lint (Clippy)
cargo clippy --all-targets --all-features -- -D warnings

# Test suite
cargo test

Running a single test (if/when tests exist):

# By test name substring
cargo test <test_name_substring>

# Integration test file
cargo test --test <test_file_name_without_rs>

# Unit tests in a specific module
cargo test <module_path>::<test_name>

If tests are added later, update this section with project-specific commands.

• src/main.rs: entrypoint and logging setup.
• src/config.rs: config file parsing/validation and CLI args.
• src/run.rs: server setup and Axum routing composition.
• src/proxy.rs: proxy routing logic and request forwarding.
• src/error.rs: minimal error type and Result alias.

• Use grouped, sorted imports similar to existing files:
  • std imports first
  • third-party imports next
  • crate imports last
• Prefer explicit use of types/modules used in a file.
• Avoid wildcard imports except when already common in Axum patterns.

• Run cargo fmt after edits.
• Keep line lengths reasonable; prefer line breaks over horizontal scrolling.
• Use Rust 2024 edition conventions; do not introduce deprecated patterns.

• Modules: snake_case (files already follow this).
• Types/structs/enums: PascalCase.
• Functions/variables: snake_case.
• Constants: SCREAMING_SNAKE_CASE.
• Avoid abbreviations unless already used in the codebase (cfg, req).

• Favor concrete types for public APIs; avoid unnecessary generics.
• Prefer borrowing (&str, &T) unless ownership is needed.
• Clone only when necessary; e.g., reqwest::Client is cheap to clone.
• Use Option and Result to model fallible or optional behavior.

• Use the crate Result<T> alias (src/error.rs).
• Convert errors into Error::AnyError via ? or into().
• Provide clear, actionable error messages (see config validation).
• For HTTP errors, use appropriate StatusCode values and readable bodies.

• Use tracing for diagnostics (info, debug, etc.).
• Respect RUST_LOG_MAX behavior in src/main.rs.
• Avoid logging sensitive data (auth headers, tokens).

• Preserve existing header forwarding rules unless intentionally changing behavior.
• When adding headers, be explicit about reasons and scope.
• Keep proxy path rewrites consistent with source_path -> dest_path.
• Do not enable WebSocket behavior unless explicitly requested.

• Config is TOML (config.toml) and required to run.
• Config::build performs minimal validation; maintain or extend as needed.
• CLI uses clap derive; add new flags in Args with clear doc comments.

• If you add tests, prefer #[tokio::test] for async code.
• Unit tests can live next to modules; integration tests in tests/.
• Keep tests deterministic; mock external HTTP calls where possible.

• Prefer standard library and existing dependencies first.
• New deps require justification and should be minimal in scope.
• If adding a dev-only tool, use [dev-dependencies].

• Do not modify config-example.toml unless required by a feature.
• Avoid changing behavior unrelated to the requested task.
• If a change impacts runtime behavior (routing, headers, auth), document it.

• There is no CI config or task runner; use cargo commands directly.
• This project is intentionally simple; keep it that way.