rustlavel-telescope: the debugging dashboard, enabled with one line.

App::new()?
    .routes(routes::web::routes)
    .plugin(Telescope::default())
    .serve()
    .await

Telescope listens on the instrumentation bus core has carried since the first release, keeps what it hears in a bounded in-memory ring buffer, and serves a single self-contained page at /telescope that shows requests, the queries and log lines each one produced, and how long everything took.

Why a ring buffer and not SQLite

Laravel Telescope writes every entry to a database. That is the right answer in PHP, where the process dies at the end of the request and there is nowhere else to put anything. Rust has a process that lives for weeks, so this crate makes two promises instead:

A debugging tool must never be the reason a request is slow. Recording an entry costs a redaction pass, a short mutex and a push onto a VecDeque — no connection, no transaction, no fsync, no await on the request's path. Optional persistence is a send into a queue that a writer thread drains; the request never waits for a disk. The buffer is bounded, so a server under load a week from now uses exactly the memory it uses today.

A debugging tool must never add a dependency to production builds. The whole crate depends on rustlavel-core and rustlavel-http and nothing else — no embedded database, no serialisation framework, not even an async runtime of its own. Persistence is JSON lines written with the JSON implementation core already has: readable with tail -f, recoverable after a kill -9 at the cost of at most the last line, and compacted at boot so the file can never outgrow the buffer it feeds.

What it records

Whatever is dispatched. The framework emits http.request, db.query and log today, and the roadmap promises ai.call, queue.job and mail.sent; an [Entry] therefore stores an open field map rather than a fixed enum, and every renderer degrades gracefully — a kind Telescope has never seen still gets a readable summary, a stable colour, a duration and a full field table.

Safety

The dashboard shows SQL, log messages, and every field a package chose to emit. So it refuses to mount in production unless someone explicitly says otherwise (telescope.enabled, or [Telescope::even_in_production]), and values under keys that look like credentials are replaced at record time — before they reach the buffer, the API, or the journal on disk.