Set up runtime environment variables

[raix]

To setup Application Insights, CDN url, cluster, region details and more in the web client we need to enable runtime environment variables.

Build environment variables are set when creating the static bundle files, these cannot be changed. Examples of these could be related to version and build related configurations. BUILD_ENV

Runtime environment variables are dynamic, they can be changed and updated by developer operations and relate to deployment specific settings. RUNTIME_ENV

To ensure that it's clear for everyone which custom runtime environment variables are sent to the client they will be suffixed with PUBLIC_ and filtered by this.

These runtime environment variables are not prefixed as they are added by the platform setup:

• PUBLIC_URL - location of the served index.html / base url
• CDN_URL - location of client bundle files
• CLUSTER_ID?
• REGION?

Solution options:

• Have an endpoint to return the runtime environment variables
  • Extra roundtrip / latency - Async / complexity
• Inject global variable in script tag
  • Content Security Policy "unsafe-inline"

Solution:

• Add runtime environment in meta tag
  This solution will prevent extra roundtrips and should not violate CSP

Developer ergonomics:

• To get an environment variable: const foo = environment.get("PUBLIC_FOO");

Tasks

Beta Give feedback

1. Configure client build to output index.html file with template placeholders (should also output in development mode)
2. Create controller in Api extracting all PUBLIC_* environment variables and serialize to json and base64 encode
3. Wait for index.html to be generated in development mode - in production mode throw exception if index.html is not found
4. Setup client build version in build pipeline