Shiny Server Deployment

Overview

ReviewR is designed to support multiple concurrent users when deployed using Shiny Server. When deployed on a centralized server an instance of ReviewR will be served to each connecting user in distinct R sessions allowing multiple participants to simultaneously connect to patient data and submit chart abstraction information. In server deployments, users will access ReviewR directly through a web browser without requiring a local R installation.

Getting Started

Before deploying ReviewR to your server, you must first configure your environment to securely host Shiny applications. The overall process consists of 5 main components:

• Obtain a domain
• Shiny Server Setup
• Configuring NGINX to Reverse Proxy Shiny Server
• Securing Shiny Server URL with Let’s Encrypt
• Deploy ReviewR

Note: This vignette assumes you have access to a server running Ubuntu 18.04.

Obtain a Domain

Using a domain registrar of your choosing, obtain a domain name for your server. There are a wide variety of registrars that will provide am domain name either for free of charge or for a small annual fee. Once you have obtained a domain name for your server, register your server’s external IP address with your domain registrar of choice. Ideally, this external IP address is static, though services exist to update DNS records for servers with ephemeral IP addresses.

Once you have registered for a domain name and linked your domain with your server’s IP you will be able to access your server with a plain text URL, rather than by a IP address. Additionally, a domain is required to encrypt connections to/from your server. This is because certificate authorities, like Let’s Encrypt, are required to verify ownership of domains before security certificates can be issued. These certificates are what allows traffic to be SSL encrypted between clients and your server via the https standard. By registering your server’s IP address with a domain registrar and associating it with a domain name, you are verifying that you own the site and take all responsibility for its functions.

Shiny Server Setup

sudo apt-get install r-base

sudo su - \
-c "R -e \"install.packages('shiny', repos='https://cran.rstudio.com/')\""

sudo apt-get install gdebi-core

wget https://download3.rstudio.org/ubuntu-14.04/x86_64/shiny-server-1.5.15.953-amd64.deb
sudo gdebi shiny-server-1.5.15.953-amd64.deb

Configuring NGINX to Reverse Proxy Shiny Server

At this stage, your Server is being hosted on port 3838 of your machine. In order to allow users to access this server via the domain that was acquired in the first portion of this guide, we will need to install and configure a reverse proxy which will direct clients securely to applications hosted on your shiny server. NGINX, an open source web server and reverse proxy will be used for the purposes of this guide.

sudo apt update
sudo apt install nginx

## substitute nano for your preferred text editor: emacs, jed, joe, pico, sandy, vi, vim, etc.
sudo nano /etc/nginx/sites-available/shiny

server {

        server_name your.shiny.server.url;

        location / {
                proxy_pass http://localhost:3838;
                proxy_redirect / $scheme://$http_host/;
                proxy_http_version 1.1;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection $connection_upgrade;
                proxy_read_timeout 20d;
                proxy_buffering off;
        }

ls -l /etc/nginx/sites-available

sudo ln -s /etc/nginx/sites-available/shiny /etc/nginx/sites-enabled/shiny

Securing Shiny Server URL with Let’s Encrypt

To begin, we will install the Certbot software on our server. This software makes it easy to secure our domain, by automatically verifying ownership, downloading and installing a Let’s Encrypt certificate, automatically configuring nginx to use the certificate, and renewing the certificate before it expires. You want this software, trust me. To install Certbot, we’ll need to add a software repository to our system. This will be accomplished by running:

sudo add-apt-repository ppa:certbot/certbot

Next, we’ll need to update our server’s package list, and install the Certbot application for our nginx configuration:

sudo apt update
sudo apt install python-certbot-nginx

As we have already configured a server block for NGINX in the previous section, we are ready to run the Certbot software to secure our domain. Run the following code block, substituting your.shiny.server.url with the domain that you configured in the nginx server block for shiny server:

sudo certbot --nginx -d your.shiny.server.url

If this is your first time running Certbot, you will be prompted to enter an email address and agree to the terms of service. After doing so, Certbot will initiate a connection with the Let’s Encrypt server and then begin testing your server to verify that you control the domain you’re requesting a certificate for. Certbot will then ask you whether or not you’d like to redirect all HTTP traffic to HTTPS traffic. It is highly recommended to do so. Please select the option for ‘Redirect’, which will ensure that users are only capable of accessing your site via secure HTTPS.

Congratulations, your Shiny Server is now secured and ready to begin hosting Shiny Applications. Continue to the next section to learn how to deploy ReviewR to your Shiny Server.

Deploy ReviewR

1. Install the ReviewR package as a root user in order to ensure your system R package library has all of the required dependencies

   • From a bash terminal, run:

     # Start R in an interactive root terminal
     sudo -i R

     This will open an interactive R console as a root user

   • From the R console that opens, run:

     # install.packages('devtools')
     devtools::install_github('thewileylab/ReviewR')

2. Continuing as the root user, fork the ReviewR repository into the Shiny Server directory (/srv/shiny-server) with the usethis package. Using the same R console from above:

   # install.packages('usethis')
   usethis::create_from_github(repo_spec = 'thewileylab/ReviewR', destdir = '/srv/shiny-server')

   This step will fork the most recent version of the ReviewR package from GitHub which includes additional files and development tools not built directly into the package. This includes an app.R file which Shiny Server will need to deploy ReviewR. By default, Shiny Server will host all applications that are placed in /srv/shiny-server

That’s it! ReviewR can now be accessed from your browser at: https://your.shiny.server.url/ReviewR