How to fix crazy long Gatsby builds on Netlify

November 07, 2021 • 2 min read • Gatsby Netlify

So I’m writing this blog post - all is good, I finish writing, checking it with Grammarly - and then I think: “OK, just three more minutes to deploy, and I’m done”.

I go to Github, create the PR for the branch with the new post, and then open Netlify to see how the deployment is going (for my PRs a new deploy is started automatically for preview.)

And I wait… and I wait.. and I wait… 10 minutes went on, I panic and I cancel the deploy. I’m thinking maybe there was a glitch in Netlify bowels and I start a new one. I wait again… Finally after 13 minutes (instead of 3) the build finishes.

I’m on the free plan (Starter) on Netlify. It includes 300 minutes/30 days of build time. For all my account websites. So if one build takes 13 minutes, I have a problem.

I run the build on my local machine, the same build runs in 2 minutes so clearly something is very wrong somewhere.

info Done building in 81.956853735 sec

But then I run the build again several times:

The second time I run the build I get some strange webpack errors:

[webpack.cache.PackFileCacheStrategy] Caching failed for pack: Error: ENOENT: no such file or directory, rename '<project_folder>.cache/webpack/stage-build-html/1.pack_' -> '<project_folder>/.cache/webpack/stage-build-html/1.pack'
...
info Done building in 35.938077026 sec

But the build is still fast.

The third time, the webpack errors are gone but the build is slow

info Done building in 375.343136062 sec

Same thing on Netlify, Caching HTML renderer compilation takes most of the build time:

My Gatsby 3 build seams blocked between onPostBuild and Caching HTML renderer compilation.

The cache is the issue. Instead of making the build faster, it makes it crazy slower 😞

Looking at my site’s netlify.toml I see that I use a deprecated plugin for caching:

[[plugins]]
  package = "netlify-plugin-gatsby-cache" # gatsby fast build

Which was ironically making my build slow.

I’ve removed it. I’ve tried using the “Essential Gatsby” plugin but I have the same issue.

After these changes, the build time is now 5 minutes. Not 3 as before but still better then 13.