const mustache = require("mustache") const actions = require("./actions") const logic = require("./logic") /** * The workflow orchestrator is a class responsible for executing workflows. * It handles the context of the workflow and makes sure each step gets the correct * inputs and handles any outputs. */ class Orchestrator { constructor(workflow) { this._context = {} this._workflow = workflow } async getStep(type, stepId) { let step = null if (type === "ACTION") { step = await actions.getAction(stepId) } else if (type === "LOGIC") { step = logic.getLogic(stepId) } if (step == null) { throw `Cannot find workflow step by name ${stepId}` } return step } async execute(context) { let workflow = this._workflow for (let block of workflow.definition.steps) { let step = await this.getStep(block.type, block.stepId) let args = { ...block.args } // bind the workflow action args to the workflow context, if required for (let arg of Object.keys(args)) { const argValue = args[arg] // We don't want to render mustache templates on non-strings if (typeof argValue !== "string") continue args[arg] = mustache.render(argValue, { context: this._context }) } const response = await step({ args, context, }) this._context = { ...this._context, [block.id]: response, } } } } module.exports = async (job, cb = null) => { try { const workflowOrchestrator = new Orchestrator(job.data.workflow) await workflowOrchestrator.execute(job.data.event) if (cb) { cb() } } catch (err) { if (cb) { cb(err) } } }