When does netlify build run locally and in the remote CI context?

The docs mention:

Like Netlify dev, Netlify build runs locally and in the remote CI context

Can more information be provided about how to know where the build actually happens and whether that’s something that can be controlled?

Also, how does it work in relation to netlify deploy? Does netlify deploy run another build?

[ehmicky]

We are trying to make local builds as similar as possible with production CI builds. This is a work in progress though and we don’t have a precise list of the small differences between both environments at the moment unfortunately.

If this issue is about https://github.com/netlify/zip-it-and-ship-it/issues/81, please feel free to add more context to that issue directly. Are you using the new Netlify Build beta in production as well, or only through the CLI?

[ehmicky]

Hi @2color, thanks for reaching out!

There are three ways to trigger a Netlify Build:

1. @netlify/build runs a Netlify build programmatically. You can require it from Node.js and call it as a normal async function.
2. Netlify CLI has a netlify deploy command which runs @netlify/build under the hood.
3. The Netlify production CI uses @netlify/build to run deployments.

Builds with 1. and 2. happen locally (e.g. on your machine) whereas 3. happens inside Netlify production CI.

If you are building a Build plugin, the best way to detect this is to use the IS_LOCAL constant. If you are simply running shell commands (e.g. inside build.command or build.lifecycle), the best way to detect this is to check whether the NETLIFY environment variable is true.

Let me know if that solves your problem!