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//! Lando provides building blocks for serverless HTTP Rust applications deployable on [AWS lambda](https://aws.amazon.com/lambda/). //! //! Lando extends the [crowbar](https://crates.io/crates/crowbar) crate with //! type-safe interfaces exposing [API gateway](https://aws.amazon.com/api-gateway/) proxy events //! as standard Rust [http](https://crates.io/crates/http) types. For convenience, //! `lando` re-exports `http::Request` and `http::Response` types. //! //! AWS lambda is a ✨ **fully managed** ✨ compute service meaning that you do not need //! to own or operate any of the servers your application will run on, freeing //! you up to **focus on your application**. You can consider Lambda AWS's Function-As-A-Service offering. //! //! Lando exports Rust functions as native CPython modules making it possible to embed //! handlers within AWS' [python3.6 runtime](https://docs.aws.amazon.com/lambda/latest/dg/python-programming-model.html). //! //! # Usage //! //! Add both `lando` and `cpython` as dependencies to your `Cargo.toml` //! //! ```toml //! [dependencies] //! cpython = "0.1" //! lando = "0.1" //! ``` //! //! Within your libraries source, use the macros from both crates //! //! ```rust,ignore //! // the following imports macros needed by the gateway macro //! #[macro_use] //! extern crate cpython; //! #[macro_use(gateway)] //! extern crate lando; //! ``` //! //! And write your function using the [gateway!](macro.gateway.html) macro //! //! ```rust //! # #[macro_use] extern crate cpython; //! # #[macro_use(gateway)] extern crate lando; //! # fn main() { //! gateway!(|_request, context| { //! println!("👋 cloudwatch logs, this is {}", context.function_name()); //! // return a basic 200 response //! Ok(lando::Response::new(())) //! }); //! # } //! ``` //! //! # Packaging functions //! //! Lando targets AWS Lambda's Python3.6 runtime. For your code to be usable //! in this execution environment, you need to compile your application as //! a dynamic library allowing it to be embedded within CPython. The //! [gateway!](macro.gateway.html) macro does //! the all the integration for you, but cargo still needs //! to know what type of lib you are compiling. //! //! You can configure cargo to build a dynamic library with the following toml. //! If you're using the //! `gateway!` macro as above, you need to use `lambda` for the library name //! (see the documentation //! for [gateway!](macro.gateway.html) if you want to use something else). //! //! ```toml //! [lib] //! name = "lambda" //! crate-type = ["cdylib"] //! ``` //! //! > 💡 `dylib` produces dynamic library embeddable in other languages. This and other link formats are described [here](https://doc.rust-lang.org/reference/linkage.html) //! //! `cargo build` will then produce an AWS-deployable `liblambda.so` binary artifact. //! Package this file in a zip file and its now deployable as an AWS Lambda function! //! Be sure to use the the Python 3.6 execution environment with the handler //! configured as `liblambda.handler`. //! //! Because you're building a dynamic library, other libraries that you're dynamically linking //! against need to also be in the Lambda execution environment. The easiest way to achive this is //! by building in an environment similar to Lambda's, like [this Docker //! container](https://hub.docker.com/r/softprops/lambda-rust/). //! extern crate base64; extern crate bytes; extern crate cpython; extern crate crowbar; extern crate http as rust_http; extern crate serde; #[macro_use] extern crate serde_derive; extern crate serde_json; // Std use std::error::Error as StdError; use std::result::Result as StdResult; // Third Party use cpython::Python; #[doc(hidden)] pub use cpython::{PyObject, PyResult}; pub use crowbar::LambdaContext; mod body; mod http; mod request; mod response; pub use body::Body; pub use http::RequestExt; pub use request::GatewayRequest; /// A re-exported version of `http::Request` with a type /// parameter for body fixed to type [lando::Body](enum.Body.html) pub type Request = rust_http::Request<Body>; /// A re-exported version of the `http::Response` type pub use rust_http::Response; /// Result type for gateway functions pub type Result = StdResult<Response<Body>, Box<StdError>>; // wrap crowbar handler in gateway handler // which works with http crate types lifting them into apigw types #[doc(hidden)] pub fn handler<F, R>( py: Python, func: F, py_event: PyObject, py_context: PyObject, ) -> PyResult<PyObject> where F: FnOnce(Request, LambdaContext) -> StdResult<Response<R>, Box<StdError>>, R: Into<Body>, { crowbar::handler( py, |event, ctx| { let apigw = serde_json::from_value::<request::GatewayRequest>(event)?; func(Request::from(apigw), ctx).map(response::GatewayResponse::from) }, py_event, py_context, ) } /// Macro that exposes a Lambda function handler for AWS API gateway proxy event triggers. /// /// Lambda functions accept two arguments (the event, a [lando::Request](type.Request.html), and a context, a /// `LambdaContext`) and are expected to return a result containing [lando::Response](struct.Response.html). The function signature should look /// like: /// /// ```rust,ignore /// fn handler(request: Request, context: LambdaContext) -> Result /// ``` /// /// To use this macro, you need to `macro_use` both crowbar *and* cpython, because crowbar /// references multiple cpython macros. /// /// ```rust,ignore /// #[macro_use(gateway)] /// extern crate lando; /// #[macro_use] /// extern crate cpython; /// ``` /// /// # Examples /// /// You can export a lambda-ready function by wrapping a closure with `gateway!`: /// /// ```rust /// # #[macro_use(gateway)] extern crate lando; /// # #[macro_use] extern crate cpython; /// # fn main() { /// gateway!(|request, context| { /// println!("{:?}", request); /// Ok(lando::Response::new(())) /// }); /// # } /// ``` /// /// You can also the provide `gateway!` macro with a named function /// /// The request argument is just a regular http::Request type but you can /// access API gateway features, like path and query string parameters, and /// stage variables by importing [lando::RequestExt`](trait.RequestExt.html) /// /// The context argument is [same type](struct.LambdaContext.html) used within the crowbar crate /// /// ```rust /// # #[macro_use(gateway)] extern crate lando; /// # #[macro_use] extern crate cpython; /// # fn main() { /// use lando::{LambdaContext, Request, Response, Result, Body}; /// /// fn handler(request: Request, context: LambdaContext) -> Result { /// println!("{:?}", request); /// Ok(Response::new("👍".into())) /// } /// /// gateway!(handler); /// # } /// ``` /// /// # Multiple functions /// /// You can export multiple functions in the same module with a format similar to a `match` expression: /// /// ```rust /// # #[macro_use(gateway)] extern crate lando; /// # #[macro_use] extern crate cpython; /// # fn main() { /// use lando::Response; /// /// gateway! { /// "one" => |request, context| { Ok(Response::new("1")) }, /// "two" => |request, context| { Ok(Response::new("2")) } /// }; /// # } /// ``` /// /// # Changing the dynamic library name /// /// Be default, lando assumes a library named "lambda", If you need to change the /// name of the resulting dynamic library that gets built, /// you first need to change the `[lib]` section in your Cargo.toml file /// /// ```toml /// [lib] /// name = "solo" /// crate-type = ["cdylib"] /// ``` /// /// You then also need to change the names of the library indentifiers, expected by /// the [cpython crate](https://dgrunwald.github.io/rust-cpython/doc/cpython/macro.py_module_initializer.html), /// by using the following `gateway!` format. This pattern may no longer needed /// the std library's [concat_idents!](https://doc.rust-lang.org/std/macro.concat_idents.html) /// macro is stablized. /// /// ```rust /// # #[macro_use(gateway)] extern crate lando; /// # #[macro_use] extern crate cpython; /// # fn main() { /// gateway! { /// crate (libsolo, initlibsolo, PyInit_libsolo) { /// "handler" => |request, context| { /// Ok(lando::Response::new( /// "hello from libsolo" /// )) /// } /// } /// }; /// # } /// ``` #[macro_export] macro_rules! gateway { (@module ($module:ident, $py2:ident, $py3:ident) @handlers ($($handler:expr => $target:expr),*)) => { py_module_initializer!($module, $py2, $py3, |py, m| { $( m.add(py, $handler, py_fn!( py, x( event: $crate::PyObject, context: $crate::PyObject ) -> $crate::PyResult<$crate::PyObject> { $crate::handler(py, $target, event, context) } ))?; )* Ok(()) }); }; (crate $module:tt { $($handler:expr => $target:expr),* }) => { gateway! { @module $module @handlers ($($handler => $target),*) } }; (crate $module:tt { $($handler:expr => $target:expr,)* }) => { gateway! { @module $module @handlers ($($handler => $target),*) } }; ($($handler:expr => $target:expr),*) => { // conventions required by cpython crate // https://dgrunwald.github.io/rust-cpython/doc/cpython/macro.py_module_initializer.html // in the future concat_indents! would be the way to make this // dynamic // see also https://www.ncameron.org/blog/untitledconcat_idents-and-macros-in-ident-position/ // https://github.com/rust-lang/rust/issues/29599 gateway! { @module (liblambda, initliblambda, PyInit_liblambda) @handlers ($($handler => $target),*) } }; ($($handler:expr => $target:expr,)*) => { gateway! { $($handler => $target),* } }; ($f:expr) => { gateway! { "handler" => $f, } }; }