File Output Cloud Storage Extension App Reference Implementation

Introduction

This reference implementation simulates an external service that writes files to cloud storage. It stores files locally or with the cloud provider of choice (AWS, Azure, or GCP). This reference implementation is useful for:

• Reviewing the format of requests to and responses from an external service that implements the file output cloud storage extension
• Seeing how the extension functions when invoked from a Maestro workflow

Authentication

This reference implementation supports two authentication flows:

• Authorization Code Grant: Required for public extension apps
• Client Credentials Grant: Available to private extension apps. See Choosing private distribution instead of public.

Private extension apps can use either authentication method, but public extension apps must use Authorization Code Grant.

Hosted version (no setup required)

You can use the hosted version of this reference implementation by directly uploading the appropriate manifest file located in the manifests/hosted/ folder to the Docusign Developer Console. See Upload your manifest and create the extension app.

Note: The provided manifest includes clientId and clientSecret values used in the sample authentication connection. These do not authenticate to a real system, but the hosted reference implementation requires these exact values.

Choose your setup: Local or cloud deployment

If you want to run the app locally using Node.js and ngrok, follow the Local setup instructions below.

If you want to deploy the app to the cloud using Docker and Terraform, see Deploying an extension app to the cloud with Terraform. This includes cloud-specific setup instructions for the following cloud providers:

• Amazon Web Services
• Microsoft Azure
• Google Cloud Platform

Local setup instructions

1. Clone the repository

Run the following command to clone the repository:

git clone https://github.com/docusign/extension-app-file-output-cloud-storage-reference-implementation.git

2. Generate secret values

• If you already have values for JWT_SECRET_KEY, OAUTH_CLIENT_ID, OAUTH_CLIENT_SECRET, and AUTHORIZATION_CODE, you may skip this step.

The easiest way to generate a secret value is to run the following command:

node -e "console.log(require('crypto').randomBytes(64).toString('hex'));"

You will need values for JWT_SECRET_KEY, OAUTH_CLIENT_ID, OAUTH_CLIENT_SECRET, and AUTHORIZATION_CODE.

3. Set the environment variables for the cloned repository

• If you're running this in a development environment, create a copy of example.development.env and save it as development.env.
• If you're running this in a production environment, create a copy of example.production.env and save it as production.env.
• Replace JWT_SECRET_KEY, OAUTH_CLIENT_ID, OAUTH_CLIENT_SECRET, and AUTHORIZATION_CODE in development.env or production.env with your generated values. These values will be used to configure the sample proxy's mock authentication server.
• Set the clientId value in the manifest.json file to the same value as OAUTH_CLIENT_ID.
• Set the clientSecret value in the manifest.json file to the same value as OAUTH_CLIENT_SECRET.

4. Install and configure Node.js and npm on your machine.

5. Install dependencies

Run the following command to install the necessary dependencies:

npm install

6. Running the proxy server

Development mode:

Start the proxy server in development mode by running the command:

npm run dev

This will create a local server on the port in the development.env file (port 3000 by default) that listens for local changes that trigger a rebuild.

Production mode:

Start the proxy server in production mode by running the commands:

npm run build
npm run start

This will start a production build on the port in the production.env file (port 3000 by default).

Set up ngrok

1. Install and configure ngrok for your machine.

2. Start ngrok

Run the following command to create a publicly accessible tunnel to your localhost:

ngrok http <PORT>

Replace <PORT> with the port number in the development.env or production.env file.

3. Save the forwarding address

Copy the Forwarding address from the response. You’ll need this address in your manifest.json file.

ngrok

Send your ngrok traffic logs to Datadog: https://ngrok.com/blog-post/datadog-log

Session Status                online
Account                       email@domain.com (Plan: Free)
Update                        update available (version 3.3.1, Ctrl-U to update)
Version                       3.3.0
Region                        United States (us)
Latency                       60ms
Web Interface                 http://127.0.0.1:4040
Forwarding                    https://bbd7-12-202-171-35.ngrok-free.app -> http:

Connections                   ttl     opn     rt1     rt5     p50     p90
                              0       0       0.00    0.00    0.00    0.00

In this example, the Forwarding address to copy is https://bbd7-12-202-171-35.ngrok-free.app.

Create an extension app

1. Prepare your app manifest

Choose a manifest from the manifests folder based on the appropriate authentication use case. Replace <PROXY_BASE_URL> in your manifest.json file with the ngrok forwarding address in the following sections:

• connections.params.customConfig.tokenUrl
• connections.params.customConfig.authorizationUrl
• actions.params.uri
  • Replace this value for all of the actions.

2. Navigate to the Developer Console

Log in with your Docusign developer credentials. You can sign up for a free developer account here.

3. Upload your manifest and create the extension app

To create your extension app, select Create App > By editing the manifest. In the app manifest editor that opens, upload your manifest file or paste into the editor itself; then select Validate. Once the editor validates your manifest, select Create App.

4. Test the extension app

This reference implementation simulates an external cloud storage service. After you have created an extension app in the Developer Console that connects to the reference implementation, you can run tests that send requests to it. Requests from the calling application are saved to the logs folder. The reference implementation sends responses to the calling application. This reference implementation processes the file output cloud storage extension's action and capabilities as follows:

• Write File: Writes the file contents supplied in the request to the location specified in the request. If you run the reference implementation locally, the file will be written to the local machine. If you run the hosted version or use a cloud deployment, you will not be able to access the location where files are written. The reference implementation supports the use of variables in folder and file names.
• List Drives: Returns mock data.
• List Directory Contents: Returns mock data.

Integration tests

You can run these tests from the Developer Console to test each supported action and capability for the extension. These tests allow you to construct the request body and see the response.

Functional tests

This type of test shows how the extension functions when invoked from an extension point. For file output cloud storage, the extension point is a Maestro workflow.