Using Rust to extend Robyn
There may be occassions where Batman may be working with a high computation task, or a task that requires a lot of memory. In such cases, he may want to use Rust to implement that task. Robyn introduces a special way to do this. Not only you can use Rust to extend Python code, you can do it while maintaining the hot reloading nature of your codebase. Making it feel like an interpreted version in many situations.
The first thing you need to is to create a Rust file. Let's call it hello_world.rs. You can do it using the cli:
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python -m robyn --create-rust-file hello_world
Then you can open the file and write your Rust code. For example, let's write a function that returns a string.
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// hello_world.rs
// rustimport:pyo3
use pyo3::prelude::*;
#[pyfunction]
fn square(n: i32) -> i32 {
n * n
// this is another comment
}
Every Rust file that you create using the cli will have a special comment at the top of the file. This comment is used by Robyn to know which dependencies to import. In this case, we are importing the pyo3 crate. You can import as many crates as you want. You can also import crates from crates.io. For example, if you want to use the rusqlite crate, you can do it like this:
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// rustimport:pyo3
//:
//: [dependencies]
//: rusqlite = "0.19.0"
use pyo3::prelude::*;
#[pyfunction]
fn square(n: i32) -> i32 {
n * n * n
// this is another comment
}
Then you can import the function in your Python code and use it.
Request
from hello_world import square
print(square(5))
To run the code, you need to use the --compile-rust-path flag. This will compile the Rust code and run it. You can also use the --dev flag to watch for changes in the Rust code and recompile it on the fly.
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python -m robyn --compile-rust-path "." --dev
An example of a Robyn app with a Rust file that using the rusqlite crate to connect to a database and return the number of rows in a table: https://github.com/sansyrox/rusty-sql
What's next?
Batman was curious to know what else he could do with Robyn.
Robyn told him to keep an eye on the GraphQl support.