Composer is a new programming model from IBM Research for composing IBM Cloud Functions, built on Apache OpenWhisk. Composer extends Functions and sequences with more powerful control flow and automatic state management. With it, developers can build even more serverless applications including using it for IoT, with workflow orchestration, conversation services, and devops automation, to name a few examples.

Composer helps you express cloud-native apps that are serverless by construction: scale automatically, and pay as you go and not for idle time. Programming compositions for IBM Cloud Functions is done via the functions shell, which offers a CLI and graphical interface for fast, incremental, iterative, and local development of serverless apps. Some additional highlights of the shell include:

• Edit your code and program using your favorite text editor, rather than using a drag-n-drop UI
• Validate your compositions with readily accessible visualizations, without switching tools or using a browser
• Deploy and invoke compositions using familiar CLI commands
• Debug your invocations with either familiar CLI commands or readily accessible visualizations

Composer and shell are currently available as IBM Research previews. We are excited about both and are looking forward to what compositions you build and run using IBM Cloud Functions or directly on Apache OpenWhisk.

We welcome your feedback and criticism. Find bugs and we will squash them. And will be grateful for your help. As an early adopter, you will also be among the first to experience even more features planned for the weeks ahead. We look forward to your feedback and encourage you to join us on slack.

This repository includes:

• tutorial for getting started with Composer in the docs folder,
• composer node.js module to author compositions using JavaScript,
• conductor action code to orchestrate the execution of compositions,
• manager node.js module to query the state of compositions,
• test-harness helper module for testing composer,
• redis-promise helper module that implements a promisified redis client for node.js,
• example compositions in the samples folder,
• unit tests in the test folder.