Deploying Serverless Functions with Execution Machine SDK
For deploying serverless functions with the SDK in JavaScript, we create a script here that tells our computer how to deploy our function to the network.
Function Logic Example
After installing the package we need a file defining the logic of the function within the project.
export async function handle(state, action) {
state.counter++;
return { state };
}
The syntax for defining functions is based off of the standard implemented by SmartWeave for smart contracts in JavaScript. Every function has a state which is a JSON object of values stored in it and actions to interact with these values.
The function above adds names to a users array which is done using the following line:
state.users.push(action.input.name);
When deploying our function we initialise an empty array named users that later helps our function to identify this state variable (variable stored in state of the function) during read and write calls. Upon initialisation the state looks like this:
{ users: [] }
Additionally, while writing to the function, we use a key named name to help the function identify what value we are feeding into the write operation. Both these definitions gain further significance when dealing with multiple values.
Once the function logic is defined and API Token is setup properly as shown here, create the deploy file as follows:
import { Exm, ContractType } from '@execution-machine/sdk';
import { readFileSync, writeFileSync } from 'fs';
// init new EXM instance
const exm = new Exm({ token: process.env.EXM_API_TOKEN });
// fetch function source
const functionSource = readFileSync('function.js');
// .deploy(source, initState, contractType)
const data = await exm.functions.deploy(functionSource, { users: [] }, ContractType.JS);
// write the function id to a local file
writeFileSync('./functionId.js', `export const functionId = "${data.id}"`)
While deploying, we need to pass in the function logic, function's initial state and programming language of function definition as arguments. To deploy, run the following command in the command line inside the appropriate directory of the project:
node deploy.js
Upon deploying we receive some data from which we store the functionId in a local file. The functionId as the name states is a unique identifier that helps in further interactions with the serverless function such as read and write operations.
The following sections walk through the process of reading and writing with EXM functions.