How to pass environment variables into pixi run?

[matthewfeickert]

For those of us who have migrated to using recipe format v1 on conda-forge with

...
conda_install_tool: pixi
...

in conda-forge.yml, conda-smithy nicely gives us a Pixi manifest with (something like)

$ pixi task list
Tasks that can run on this machine:
-----------------------------------
build, build-linux_64_, build-locally, inspect-all, inspect-linux_64_, lint, rerender, smithy

 - build           Build yarr-feedstock directly (without setup scripts), no particular variant specified
 - build-linux_64_ Build yarr-feedstock with variant linux_64_ directly (without setup scripts)
 - build-locally   Build packages locally using the same setup scripts used in conda-forge's CI
 - inspect-all     List contents of all packages found in rattler-build build directory.
 - inspect-linux_64_ List contents of yarr-feedstock packages built for variant linux_64_
 - lint            Lint the feedstock recipe
 - rerender        Rerender the feedstock.
 - smithy          Run conda-smithy. Pass necessary arguments.

For conda-build and rattler-build the environment variable to control the number of cores used in the build is CPU_COUNT. If I'm running a local build of a project I want to speed it up and so I'd want to run

pixi run build-locally

with something like CPU_COUNT=10.

However,

CPU_COUNT=10 pixi run build-locally

doesn't set CPU_COUNT to 10 in the pixi environment.

diff --git a/recipe/recipe.yaml b/recipe/recipe.yaml
index 3ad513d..5424301 100644
--- a/recipe/recipe.yaml
+++ b/recipe/recipe.yaml
@@ -22,6 +22,7 @@ build:
...
+    - echo "CPU_COUNT ${CPU_COUNT}"
...

but at runtime

 │ │ + echo 'CPU_COUNT 2'

In

$ pixi --version
pixi 0.44.0

or later how can shell environment variables be passed into pixi run environments from the command line?

[matthewfeickert]

The answer is to do exactly as I was doing

ENV_VAR=VALUE pixi run <task name>

The reason

CPU_COUNT=10 pixi run build-locally

doesn't work is because build-locally runs .scripts/run_docker_build.sh which doesn't take its values directly from the environment.

CPU_COUNT=10 pixi run build-linux_64_

works as expected and great though. 👍