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Deploying the Web App

Source: vignettes/dev-deploy-app.Rmd
dev-deploy-app.Rmd

Hosting the Web App

These issues might be relevant to deploying/hosting:

Consider the isPublic parameter

Consider the isPublic parameter as set in the file app.R – The isPublic flag determined whether to show the public/basic or expert version of the web application. See the help in ejamapp() and for more details see Defaults and Custom Settings for the Web App. One way to improve this process would be to modify the isPublic toggle to be an environment variable. This would allow us to set the value once in each application server, and not have to change it each time we push updates. Moreover, it would make testing the app easier to handle in the GitHub actions (see shinytests vignette). Note that after mid-2025 the isPublic setting is defined in the file app.R and has been handled as explained in the article Defaults and Custom Settings for the Web App.

Consider other parameters

Consider the other parameters like logo-related and app title parameters, defined in the files global_defaults_package.R or global_defaults_shiny.R. See the help in ejamapp() and for more details see Defaults and Custom Settings for the Web App.

Update EJAM Application

Update the app. See Updating the Package as a New Release vignette.

Decide which branch to deploy from

Update the branch from which the app will be deployed, which could be a different branch, such as “deploy-from” if that is useful.

Deploy via Docker, AWS, Posit Connect/Cloud, or whatever approach you prefer

1. Using Docker/AWS for hosting

The live EJAM app in 2025 was being hosted via AWS and Docker using the Dockerfile now included with the EJAM package, and is hosted at a URL you can be directed to from this shortcut: https://ejanalysis.org/ejamapp The EJAM fork at https://github.com/Environmental-Policy-Innovation-Center/ejam-mc-pedp shows how the deployment works, but essentially it is based on the Dockerfile.

The EJAM-API is deployed via Docker as well, and that repository shows how the deployment works.

The EPA-hosted (pre-2025) app used Posit Connect for hosting.

2. Using Posit Connect (or Posit ConnectCloud) for Hosting

Shiny apps can be hosted using Posit Connect or Posit Connect Cloud, which are commercial products that have a full set of features focused on hosting shiny apps and APIs based on R/Python.

  • Configure Posit Connect to deploy from a github.com repository - The EPA-hosted (pre-2025) app used a Posit Connect server configured to re-publish the shiny app directly from github.com content whenever it saw changes in the specified repo and branch, and that same approach could be used by anyone else hosting the app.

  • Handle dependencies with Posit Connect - Posit Connect uses the rsconnect package and tracks where each package was installed from, including EJAM itself, so EJAM should be installed from github. See notes on doing that, in the file EJAM/data-raw/rsconnect-manifest-update.R Also note that if the renv package is being used to handle dependencies then publishing to Posit Connect has to take that into account as explained here: https://rstudio.github.io/renv/articles/rsconnect.html

  • Update the manifest.json file to deploy to Posit Connect/Cloud - If using Posit, use a script like EJAM/data-raw/rsconnect_manifest_update.R to update the manifest file.