ADAPT-2326: Update Algolia to only index on prod builds.

[nplowman]

READY FOR REVIEW

Summary

• Prevents Algolia indexing from getting triggered on non-production builds.
• The new method uses the deploy context environment variable provided by Netlify. (See Resources section)

Review By (Date)

• Not urgent - before end of sprint.

Criticality

• Moderate. Under the status quo without this fix, indexing is happening unnecessarily on preview builds.

Review Tasks

Setup tasks and/or behavior to test

The easiest way to validate this is to check the build logs on Netlify.

On the preview builds, you should now see a line like this:

3:12:37 PM: success index to Algolia - 0.002s - options.skipIndexing is true; skipping indexing

This one you can check by simply looking at the build log for this PR as I did.

We'll also want to make sure the indexing is still working on prod builds.
You should see a line like this in the logs on the production build after this ticket is merged:

3:20:14 PM: success index to Algolia - 3.201s - Done!

As an additional validation step, you can also check the Index logs on Algolia
https://www.algolia.com/apps/SA452GABN1/explorer/logs/Giving%20to%20Stanford

If the Gatsby plugin attempted to index during the build, you will see one or more log entries that have the 'x-aloglia-agent' flag, like this:

This should show up on Production builds, and should NOT show up on Preview builds.

Front End Validation

• Is the markup using the appropriate semantic tags and passes HTML validation?
• Cross-browser testing has been performed?
• Automated accessibility scans performed?
• Manual accessibility tests performed?
• Design is approved by @ user?

Backend / Functional Validation

Code

• Are the naming conventions following our standards?
• Does the code have sufficient inline comments?
• Is there anything in this code that would be hidden or hard to discover through the UI?
• Are there any code smells?
• Are tests provided? eg (unit, behat, or codeception)

Code security

• Are all forms properly sanitized?
• Any obvious security flaws or new areas for attack?

General

• Is there anything included in this PR that is not related to the problem it is trying to solve?
• Is the approach to the problem appropriate?

Affected Projects or Products

• Does this PR impact any particular projects, products, or modules?

Associated Issues and/or People

• https://stanfordits.atlassian.net/browse/ADAPT-2326

Resources

• Info on CONTEXT variable: https://stanfordits.atlassian.net/browse/ADAPT-2326
• More info on Deploy Contexts: https://docs.netlify.com/site-deploys/overview/#deploy-contexts

[sherakama]

GTG