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Orcha

AWS Lambda Orchestrator. Allows you to give a JSON workflow file written in the Amazon States Language, and execute lambda functions based on your workflow. You can open your workflow in the UI to see a tree diagram of your workflow, run the workflow based on the inputs you specify, and see the diagram update in real-time as your workflow runs on AWS. Executing your workflow requires that you have already created those lambda functions in AWS and have access to them.

Prerequisites

You need to have access to your lambda functions through the AWS CLI. To test whether you do, run this in your terminal:

aws lambda list-functions

You should see a list of your lambda functions.

Installing

Clone the repo and then run:

npm install

Creating workflows

The workflow files should be written in the Amazon States Language. The only difference between the workflow format and ASL is in the workflow syntax, you specify a "LambdaToInvoke" (which is just the name of the lambda function) instead of an arn "Resource". See test/json_workflow_file_test_cases for example workflow files. These examples are used by the unit tests in test/orcha.test.js

Running your workflow

To run your workflow, require the source file, and run executeWorkflow:

const orcha = require('./src/orcha);
orcha.executeWorkflow({
    jsonPath,
    workflowObject,
    workflowInput, 
    region, 
    endOfExecutionCallback,
    statusUpdateCallback,
    errorCallback
});

Required arguments: workflowInput, region, endOfExecutionCallback, jsonPath OR workflowObject

Optional arguments: statusUpdateCallback, errorCallback

jsonPath is the path to your workflow, workflowInput is the input to your first lambda, region is the AWS region where your lambdas are, endOfExecutionCallback is a function that will run after your workflow is complete, workflowObject is a JSON workflow object that you can pass in instead of passing in the jsonPath argument.

statusUpdateCallback is a callback function you can specify that will run after a status update in your workflow (such as a lambda function starting or ending). errorCallback is a callback function you can specify that will run if your workflow fails. Both statusUpdateCallback and errorCallback are optional, but recommended.

An example of how you could run a workflow and log the result to the console:

orcha.executeWorkflow({
    jsonPath: 'test.json', 
    workflowInput: {users: ['Alice', 'Bob', 'Charlie']}, 
    region: 'us-east-1', 
    endOfExecutionCallback: (workflowOutput) => console.log(workflowOutput)
});

Using the Application

To run the UI first build the React application:

npm run bundle

Then run the application:

npm run serve

You can then open a workflow file (Ctrl+O) to view the workflow tree. To run your workflow, enter a JSON object input into the input panel, and run your workflow by entering Ctrl+R. You will see the lambda states change color as they are invoked and return from completion on AWS.

Running the tests

To run the unit tests:

npm test