Add Rust environment to the catalog and docs

content/en/_index.html

@@ -121,8 +121,8 @@ <h4 class="section-text-bold">
           </h4>
           <p class="section-text">
             Fission is extensible to any programming language (Python, NodeJS,
-            Go, C#, PHP are supported today). It abstracts away containers by
-            default, but you can build your own containers if you need to.
+            Go, Rust, C#, PHP are supported today). It abstracts away containers
+            by default, but you can build your own containers if you need to.
           </p>
         </div>
       </div>
@@ -238,8 +238,8 @@ <h4 class="section-text-bold">Wide Language Support</h4>
           </div>
           <p class="section-text">
             Fission is extensible to any programming language of your choice.
-            Python, NodeJS, Go, C#, PHP are supported today, but you can build
-            your own custom containers if you need to.
+            Python, NodeJS, Go, Rust, C#, PHP are supported today, but you can
+            build your own custom containers if you need to.
           </p>
         </div>
       </div>

content/en/docs/usage/languages/_index.md

@@ -21,6 +21,7 @@ Each environment has a runtime image (`*-env`) and, where dependency building is
 | Node.js | `ghcr.io/fission/node-env` | `ghcr.io/fission/node-builder` | [Node.js]({{% ref "nodejs.md" %}}) |
 | Python | `ghcr.io/fission/python-env` | `ghcr.io/fission/python-builder` | [Python]({{% ref "python.md" %}}) |
 | Go | `ghcr.io/fission/go-env` | `ghcr.io/fission/go-builder` | [Go]({{% ref "go.md" %}}) |
+| Rust | `ghcr.io/fission/rust-env` | `ghcr.io/fission/rust-builder` | [Rust]({{% ref "rust.md" %}}) |
 | Java (JVM) | `ghcr.io/fission/jvm-env` | `ghcr.io/fission/jvm-builder` | [Java]({{% ref "java.md" %}}) |
 | Ruby | `ghcr.io/fission/ruby-env` | `ghcr.io/fission/ruby-builder` | [environments repo](https://github.com/fission/environments/tree/master/ruby) |
 | PHP | `ghcr.io/fission/php-env` | `ghcr.io/fission/php-builder` | [environments repo](https://github.com/fission/environments/tree/master/php7) |

content/en/docs/usage/languages/rust.md

@@ -0,0 +1,321 @@
+---
+title: "Rust Functions"
+description: "Writing Rust functions with fission"
+weight: 10
+---
+
+Fission supports Rust as a first-class function language.
+Rust functions are compiled by the builder into native server binaries built on [axum](https://docs.rs/axum) and [tokio](https://tokio.rs), so invocations run at native speed with no per-request process startup.
+
+In this usage guide we'll cover how to use this environment, write functions, and work with dependencies.
+
+### Before you start
+
+We'll assume you have Fission and Kubernetes set up.
+If not, head over to the [install guide]({{% ref "../../installation/_index.en.md" %}}).
+Verify your Fission setup with:
+
+```bash
+fission version
+```
+
+### Add the Rust environment to your cluster
+
+Rust is a compiled language, so source code must be compiled before it runs.
+The builder manager inside Fission does this automatically whenever a Rust function or package is created: the Rust builder converts a source package into a deployable native binary.
+
+```bash
+fission environment create --name rust \
+  --image ghcr.io/fission/rust-env \
+  --builder ghcr.io/fission/rust-builder
+```
+
+#### Rust environment image list
+
+| Image | Builder Image |
+|-------|---------------|
+| [ghcr.io/fission/rust-env](https://github.com/fission/environments/pkgs/container/rust-env/versions?filters%5Bversion_type%5D=tagged) | [ghcr.io/fission/rust-builder](https://github.com/fission/environments/pkgs/container/rust-builder/versions?filters%5Bversion_type%5D=tagged) |
+
+### Write a simple function in Rust
+
+A single-file function is one `.rs` file that defines `pub async fn handler`.
+Any [axum handler](https://docs.rs/axum/latest/axum/handler/index.html) signature works, so you can use extractors, `Json`, headers, and so on.
+
+Here is a hello world example (`hello.rs`):
+
+```rust
+use fission_rust::IntoResponse;
+
+pub async fn handler() -> impl IntoResponse {
+    "Hello, World!\n"
+}
+```
+
+Create and test the function:
+
+```bash
+fission fn create --name helloworld --env rust --src hello.rs
+```
+
+Before accessing the function, make sure its package build has succeeded:
+
+```bash
+fission pkg info --name <pkg-name>
+```
+
+Now test it:
+
+```bash
+$ fission fn test --name helloworld
+Hello, World!
+```
+
+{{% notice info %}}
+See [here]({{% ref "../triggers/_index.md" %}}) for how to set up different triggers for a Rust function.
+{{% /notice %}}
+
+Single-file functions may use the crates pre-baked into the builder: `fission-rust`, `axum`, `tokio`, `serde`, and `serde_json`.
+For other dependencies, use a [Cargo project](#working-with-dependencies-cargo-projects).
+
+### HTTP requests and HTTP responses
+
+The function receives every request routed to it; axum extractors give you typed access to all parts of the request.
+
+#### Accessing HTTP Requests
+
+##### Headers
+
+```rust
+use fission_rust::IntoResponse;
+use fission_rust::axum::http::HeaderMap;
+
+pub async fn handler(headers: HeaderMap) -> impl IntoResponse {
+    let v = headers
+        .get("x-my-header")
+        .and_then(|v| v.to_str().ok())
+        .unwrap_or("not set");
+    format!("x-my-header: {v}\n")
+}
+```
+
+Create an HTTP trigger and call it:
+
+```bash
+fission httptrigger create --method GET --url "/<url>" --function <fn-name>
+```
+
+```bash
+$ curl http://$FISSION_ROUTER/<url> -H 'X-My-Header: foo'
+x-my-header: foo
+```
+
+##### Query string
+
+```rust
+use std::collections::HashMap;
+use fission_rust::IntoResponse;
+use fission_rust::axum::extract::Query;
+
+pub async fn handler(Query(params): Query<HashMap<String, String>>) -> impl IntoResponse {
+    params.get("key-name").cloned().unwrap_or_default()
+}
+```
+
+```bash
+$ curl "http://$FISSION_ROUTER/<url>?key-name=123"
+123
+```
+
+##### Request Body
+
+###### Plain text
+
+```rust
+use fission_rust::IntoResponse;
+
+pub async fn handler(body: String) -> impl IntoResponse {
+    body
+}
+```
+
+```bash
+$ curl -X POST http://$FISSION_ROUTER/<url> -d foobar
+foobar
+```
+
+###### JSON
+
+```rust
+use fission_rust::IntoResponse;
+use fission_rust::axum::Json;
+use serde::{Deserialize, Serialize};
+
+#[derive(Deserialize, Serialize)]
+pub struct Msg {
+    content: String,
+}
+
+pub async fn handler(Json(msg): Json<Msg>) -> impl IntoResponse {
+    Json(msg)
+}
+```
+
+```bash
+$ curl -X POST http://$FISSION_ROUTER/<url> \
+    -H 'Content-Type: application/json' -d '{"content": "foobar"}'
+{"content":"foobar"}
+```
+
+#### Controlling HTTP Responses
+
+##### Setting response headers and status codes
+
+Return a tuple of status, headers, and body — axum converts it into a response:
+
+```rust
+use fission_rust::IntoResponse;
+use fission_rust::axum::http::StatusCode;
+
+pub async fn handler() -> impl IntoResponse {
+    (
+        StatusCode::CREATED,
+        [("x-request-handled-by", "fission-rust")],
+        "created\n",
+    )
+}
+```
+
+```bash
+$ curl -i http://$FISSION_ROUTER/<url>
+HTTP/1.1 201 Created
+x-request-handled-by: fission-rust
+...
+```
+
+Handler panics are caught by the runtime: the request returns HTTP 500 and the function keeps serving.
+
+### Multiple module files
+
+A source archive may contain a `handler.rs` plus extra module files.
+Each file becomes a crate-root module, so `handler.rs` can reach a sibling `util.rs` as `crate::util`:
+
+```rust
+// util.rs
+pub fn greeting() -> String {
+    "Hello from a sibling module!\n".to_string()
+}
+```
+
+```rust
+// handler.rs
+use fission_rust::IntoResponse;
+
+pub async fn handler() -> impl IntoResponse {
+    crate::util::greeting()
+}
+```
+
+```bash
+zip -r function.zip handler.rs util.rs
+fission pkg create --name multimod --env rust --src function.zip
+```
+
+### Working with dependencies (Cargo projects)
+
+For third-party crates, supply a full Cargo binary crate as the source package.
+The only contract: **the binary must serve HTTP on `127.0.0.1:$FISSION_RUNTIME_PORT`**.
+
+The easiest way is the `fission-rust` SDK:
+
+```toml
+# Cargo.toml
+[package]
+name = "echo-example"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+fission-rust = { git = "https://github.com/fission/environments", rev = "<commit-sha>" }
+tokio = { version = "1", features = ["rt-multi-thread", "macros"] }
+serde_json = "1"
+```
+
+Pin the dependency to a commit with `rev` for reproducible builds.
+Without `rev` the git dependency tracks `master` and can change under you between builds; pinning a `rev` keeps every build resolving the same source.
+The builder pod fetches the crate over the network at build time, so the builder needs egress to GitHub — the same as for any crates.io dependency.
+
+```rust
+// src/main.rs
+use fission_rust::IntoResponse;
+use fission_rust::axum::Json;
+use serde_json::Value;
+
+async fn handler(body: String) -> impl IntoResponse {
+    let value: Value = serde_json::from_str(&body)
+        .unwrap_or_else(|_| Value::String(body));
+    Json(value)
+}
+
+#[tokio::main]
+async fn main() {
+    fission_rust::serve(handler).await;
+}
+```
+
+Archive and create the package as usual:
+
+```bash
+$ zip -r echo.zip Cargo.toml src
+$ fission pkg create --name echo --env rust --src echo.zip
+$ fission fn create --name echo --env rust --pkg echo
+```
+
+#### Bring your own framework
+
+Because the contract is just "serve HTTP on `$FISSION_RUNTIME_PORT`", any Rust web framework works — actix-web, rocket, warp, or raw hyper:
+
+```rust
+// src/main.rs — plain axum without the SDK
+use axum::{Router, routing::get};
+
+#[tokio::main]
+async fn main() {
+    let port: u16 = std::env::var("FISSION_RUNTIME_PORT")
+        .ok().and_then(|p| p.parse().ok()).unwrap_or(8889);
+    let app = Router::new().route("/", get(|| async { "Hello!\n" }));
+    let listener = tokio::net::TcpListener::bind(("127.0.0.1", port)).await.unwrap();
+    axum::serve(listener, app).await.unwrap();
+}
+```
+
+#### Multiple binaries and entrypoints
+
+If the project defines several `[[bin]]` targets, the builder deploys all of them and the function's `--entrypoint` selects one by name:
+
+```bash
+fission fn create --name myfn --env rust --pkg mypkg --entrypoint <binary-name>
+```
+
+A project with a single binary needs no entrypoint — it is always deployed under the default name `handler`.
+
+### How it works
+
+The runtime image runs a small supervisor that implements the Fission environment interface.
+At specialization it starts your compiled function binary **once** and then reverse-proxies all requests to it over a pooled local connection, so steady-state overhead is a single localhost hop.
+If the function process exits, the pod is replaced automatically.
+
+### Modifying/Rebuilding the environment images
+
+Refer to the [Rust environment guide](https://github.com/fission/environments/blob/master/rust/README.md) to learn about rebuilding the environment images.
+
+### Resource usage
+
+Like any function, you can bound a Rust function's resources:
+
+```bash
+fission fn create --name echo --env rust --pkg echo \
+                  --mincpu 20 --maxcpu 100 --minmemory 64 --maxmemory 128
+```
+
+Compiled Rust functions are typically small (a hello world binary is around 1 MB) and have low memory floors, so they are a good fit for tight resource limits.
+Use `kubectl top pod -l functionName=<name>` while benchmarking to find the right values.

static/data/environments.json

@@ -32,6 +32,17 @@
             }
         ]
     },
+    {
+        "name": "Rust",
+        "logo": "/images/lang-logo/rust-logo.svg",
+        "repo": "https://github.com/fission/environments/tree/master/rust",
+        "images": [
+            {
+                "main": "rust-env",
+                "builder": "rust-builder"
+            }
+        ]
+    },
     {
         "name": "Python",
         "logo": "/images/lang-logo/python-logo.svg",

tools/environments.py

@@ -8,6 +8,7 @@
     'jvm-env': 'Java',
     'jvm-jersey-env-25': 'Java (JVM-Jersey)',
     'ruby-env': 'Ruby',
+    'rust-env': 'Rust',
     'python-env': 'Python',
     'python-fastapi-env': 'Python (FastAPI)',
     'binary-env': 'Misc',