drift file

Everything you do with a Driftfile, under one noun. The file declares what runs on a slice, which source files fill which slots, while the slice's own shape and price are chosen in drift slice create/resize. One noun, so there is nothing to learn about where a verb lives before you can type it.

Five of these never leave your laptop: no account, no slice, no network, so “is line 9 a typo?” costs milliseconds instead of a failed deploy.

A bare path argument defaults to ./Driftfile, and a directory argument means the Driftfile inside it.

The rest apply the file, or run what it declares:

The four local verbs are one loop: run boots the whole project in Docker, test runs the Driftfile's tests.e2e commands against it, logs tails it, and stop tears it down.

Environments

When the Driftfile declares environments:, apply, simulate, run, test, stop and logs all take one as a positional argument (or --env). It decides which environment's overrides merge onto the base shape, and which slice the command targets: prod/production, and the one slice a project with no environments declares, target the bare slice name; every other environment targets <slice>-<env>, which has to already exist as a slice drift slice create made. With no argument, the target is prod/production when declared, or the single slice otherwise.

Running locally

drift file run builds every function and the Canvas site, bakes a thin image on top of the Drift runtime, and launches it detached on localhost: the same code that runs on Drift Cloud, on your own machine. It needs Docker, and only Docker: every language (Go, Rust, Python, Node, PHP, Ruby) builds inside a throwaway container, so no toolchain has to be installed locally. Set DRIFT_RUN_HOST_BUILD=1 to build with your own installed toolchains instead, which is faster and pulls nothing.

Apply flags

Testing before you ship

drift file test is run plus your own e2e commands. It starts the project locally, waits for it to report healthy, exports the instance URL as DRIFT_TEST_URL (the port is chosen at runtime, so read it rather than hardcoding one), and runs every command under tests.e2e. The first non-zero exit fails the run, and the instance is torn down either way.

# Driftfile
tests:
  e2e:
    - npx playwright test

# then, with no account and no cloud:
$ drift file test

resolve is the one that pays for itself. An environment block that sets three knobs looks like it describes the slice, when it describes three knobs on top of a base you're holding in your head. It prints no price: the server is the single authority on cost, and drift file apply --plan is where that number comes from. It prints names of secrets, never values.

explain answers the other question, the one about the format rather than about your file. drift file explain backbone.nosql prints what that key is, what it may contain, and which of its fields are required, the way kubectl explain does for a manifest field. It renders the schema the CLI already caches, which is the same document lint validates against, so the two can never disagree and a key the platform adds is explainable as soon as the cache refreshes. Where a key accepts more than one spelling, every accepted form is shown rather than the first.

Every key the file accepts is in the Driftfile reference.