typescript

Typescript for OpenFaas

Makes use of TS Node bheind the scenes for compilation and execution. Uses Express for handling REST requests

Usage

New functions can be created through the faas-cli like:

faas-cli new hello-world --lang typescript

The basic contract for the functions goes as follows:

• The handler function must be an async default export from the handler.ts file
• The handler function takes in context and event information and returns a promise of result information
• The context contains relevant evironment variables and secrets that are known to the function
• The event contains the arguments for the function to process
• The result promise could contain a data structure, string message or just null

Basics

A base-bones handler that does not care about the context could look like:

import { FnContext, FnEvent, FnResult } from "./types"

export default async function(_: FnContext, event: FnEvent): Promise<FnResult> {
   // do something
   return null
}

A handler to create something something based on a dictionary of values could look like:

import { FnContext, FnEvent, FnResult } from "./types"

export default async function(_: FnContext, event: FnEvent): Promise<FnResult> {
   const data = event.body
   // do something
   return null
}

A handler that needs a password (for a database connect, etc), does something and returns a simple message could look like:

import { Connection } from 'somedb'
import { FnContext, FnEvent, FnResult } from "./types"

export default async function(context: FnContext, event: FnEvent): Promise<FnResult> {
   const connection = new Connection({
      username: context.secrets.get('username'),
      password: context.secrets.get('password')
   })

   // do something
   return 'ok'
}