Add Netlify Gatsby cache plugin

[ehmicky]

This adds Netlify Gatsby cache plugin.

This plugin was previously added but removed due to a bug reported here.

I could not reproduce the problem, so I think this might have been fixed in the latest Netlify Build since we fixed several caching-related issues.

I am going to try to push to this PR several times in a row to ensure that the problem you encountered is not there anymore. Please keep this PR open until I can confirm everything looks good, thanks!

[RNR1]

i think that's the problem i am experiencing either, thanks!

[ehmicky]

@RNR1 Could you please describe your problem? I am looking for any additional debugging information.

If possible, please do so by posting a new issue on https://github.com/netlify/build/issues. Thanks!

[RNR1]

well after checking for further info in the issue, i'm not sure that's it, my problem is on getting the images from cache when running npm run develop. then it's not showing the category photos on main page.

[jasonLaster]

@ehmicky do we want to also restrict the CDN publish to the public directory?

[ehmicky]

It turns out only the public directory is published to the CDN, so all is good there 👍

I have investigated more this issue and summarized my findings in this comment. In a nutshell I would recommend:

• First fixing [build warning] Warning message with gatsby-source-filesystem #199 and [build warning] You specified a fileNode, but we caught an error #81
• Then merging this PR
• If the problem is still occurring, re-opening Builds start failing after awhile netlify/build#1069

[jasonLaster]

Thanks @ehmicky

[bahmutov]

@ehmicky you are fixing Netlify plugins here and NOT suggesting using Cypress for testing either on Netlify or on GitHub, I am disappointed

[jasonLaster]

@bahmutov i wouldn't be surprised if every climate site were using cypress in the next couple of months 😉

I'd be happy to pair on our first test anytime you'd like.