Key Value Store

Key value functions are available in the spin_sdk::key_value module. The function names match the operations above. For example:

use anyhow::Result;
use spin_sdk::{
    http::{Request, Response},
    http_component,
    key_value::{Store},
};
#[http_component]
fn handle_request(_req: Request) -> Result<Response> {
    let store = Store::open_default()?;
    store.set("mykey", "myvalue")?;
    let value = store.get("mykey")?;
    Ok(http::Response::builder().status(200).body(Some(value.into()))?)
}

General Notes

set Operation

• For set, the value argument can be of any type that implements AsRef<[u8]>

get Operation

• For get, the return value is of type Vec. If the key does not exist then Error::NoSuchKey is returned.

open Operation

• The close operation is not surfaced; it is called automatically when the store is dropped.

set_json and get_json Operation

• Rust applications can store and retrieve serializable Rust types.

With Typescript, the key value functions can be accessed after opening a store using either the Kv.open or the Kv.openDefault methods which returns a handle to the store. For example:

import { HandleRequest, HttpRequest, HttpResponse, Kv } from "@fermyon/spin-sdk"

export const handleRequest: HandleRequest = async function (request: HttpRequest): Promise<HttpResponse> {
    let store = Kv.openDefault()
    store.set("mykey", "myvalue")
    return {
            status: 200,
            headers: {"content-type":"text/plain"},
            body: store.get("mykey") ?? encoder.encode("Key not found")
    }
}

General Notes

• The spinSdk object is always available at runtime. Code checking and completion are available in TypeScript at design time if the module imports anything from the @fermyon/spin-sdk package. For example:

get Operation

• The result is of the type ArrayBuffer | null
• If the key does not exist, get returns null (no error is thrown)

set Operation

• The value argument is of the type ArrayBuffer | string.

setJson and getJson Operation

• JavaScript and TypeScript applications can store JavaScript objects using setJson; these are serialized within the store as JSON. These serialized objects can be retrieved and deserialized using getJson. If you call getJson on a key that doesn’t exist then an error is thrown (note that this is different behavior from get).

The key value functions are provided through the spin_key_value module in the Python SDK. For example:

from spin_http import Response
from spin_key_value import kv_open_default


def handle_request(request):

    store = kv_open_default()
    store.set("mykey", "myvalue")
    value = store.get()
    //
    return Response(status, [("content-type", "text/plain")], value)   

General Notes

get Operation

• If a key does not exist, it returns None

Key value functions are provided by the github.com/fermyon/spin/sdk/go/key_value module. See Go Packages for reference documentation.. For example:

import "github.com/fermyon/spin/sdk/go/key_value"

func example() error {
    store, err := key_value.Open("default")
    if err != nil {
        return err
    }
    defer key_value.Close(store)
    return key_value.Set(store, "mykey", []byte("myvalue"))
}