Ossido 0.1.9: OpenTelemetry and a faster dev loop

0.1.9 is about seeing what your app is doing and spending less time waiting on it. It adds built-in OpenTelemetry, makes .env edits and route changes apply without restarting ossido dev, teaches ossido build to compile the release server for you, and ships four new examples to start from.

OpenTelemetry, built in

Ossido can now export traces and logs over OTLP to any collector - Jaeger, Grafana, Honeycomb, or otel-tui on your laptop. There's nothing to configure in Ossido itself. Set the standard environment variable and it's on:

OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318 ossido dev

With no OTEL_* variables set, nothing is exported. Once it's on, you get these without writing any code:

• a server span for every request, named after its route and continuing any incoming traceparent;
• a child span for each page handler, #[api] route and #[action];
• spans for each phase of server rendering, including time spent queued for a render pool worker;
• every Ossido log, and every logger call, exported as a log record linked to its request's trace. Console output is unchanged.

tracing is re-exported as ossido::tracing, so your own spans join the same traces:

use ossido::tracing;

fn build_subtitle() -> String {
    tracing::info_span!("build_subtitle").in_scope(|| "Traced".to_string())
}

OpenTelemetry lives behind the telemetry Cargo feature, which is on by default. If you'd rather not carry the dependencies, set default-features = false on the ossido crate. The OpenTelemetry docs cover the supported variables and the full list of spans.

A faster dev loop

Two of the most common reasons to restart ossido dev are gone.

.env hot reloads. Edit a .env file while the dev server is running and it's reloaded inside the running server. get_env! and server rendering pick up the new values right away. The process environment (std::env) is deliberately left alone, since changing it under a live, multi-threaded server isn't safe - so read settings through get_env! if you want them to update live. See Environment Variables.

The router hot swaps. An edited route component swaps into the running app without a full page reload, and adding or removing a route swaps in the regenerated route tree. The watcher now notices files being created and deleted, not just edited: a new .rs route rebuilds and restarts the server, and a deleted route stops being served after a hard refresh.

Along the way we fixed a hard-refresh bug and HMR firing more often than it needed to.

ossido build compiles the server

For server output, ossido build now also runs cargo build --release and tells you where the binary ended up and how big it is. One command now produces everything you deploy.

If something else already compiles the binary, such as a Dockerfile with its own cargo build --release step, pass --no-cargo to skip it:

ossido build --server --no-cargo

The output is cleaner too. Each step - scaffolding, types, the app bundle, the server compile, static generation - gets a line in a short checklist with its own spinner, and the route tree and emitted files are printed once at the end. Build hook logs appear dimmed underneath, CI and piped output get plain lines instead of spinners, and -v/--verbose shows everything Vite and cargo print. See The CLI.

Four new examples

There are four new starters, each one ossido new --template <name> away:

ossido new my-app --template kitchen-sink

The full list is in Installation.

Fixes

• Middleware scope - a folder's middleware.rs now applies only to that folder and its subfolders. Before, it could also wrap sibling routes merged before it, so api/middleware.rs was also covering routes like /benchmarks.
• Duplicate imports - two state-using #[action] or #[handler] functions in one file no longer fail to compile with E0252.
• Nested generics - generated TypeScript types keep nested generics, so Option<Vec<T>> and Json<Vec<T>> are no longer flattened.
• actions.ts - only imports the helpers it uses, so noUnusedLocals is happy.
• Empty routers - folders with no Rust routes, such as MDX-only docs pages, no longer add empty Router::new() merges to the generated main.rs.
• rusty_v8 is pinned to a known-good version.

Upgrading

Run ossido upgrade, or pin the version:

ossido upgrade --version 0.1.9

There are no breaking API changes, but three behaviour changes are worth knowing about:

• ossido build takes longer by default, because it now includes a release compile of the server. Pass --no-cargo if you build the binary separately.
• A subfolder's middleware.rs no longer applies to its sibling routes. If a route relied on that, move the middleware up to a shared parent folder.
• The OpenTelemetry dependencies are included by default. Set default-features = false on the ossido crate to drop them.

The full diff is in the 0.1.9 release notes (0.1.8...0.1.9).