Error when trying to use sccache: `error: unrecognized subcommand`

[gdubicki]

Hi,

I am trying to use sccache v0.8.0 to cache Rust compilation for Rust v1.78.0.

I am running my code in a Docker image rust:1.78.0-bullseye.

I start my container like this:

docker run -it --platform linux/amd64 -v $(pwd):/app rust:1.78.0-bullseye /bin/bash

And then download and configure sccache like this:

# Get binary because compiling it would be slooooow, of course...
wget https://github.com/mozilla/sccache/releases/download/v0.8.0/sccache-dist-v0.8.0-x86_64-unknown-linux-musl.tar.gz
tar xfvz sccache-dist-v0.8.0-x86_64-unknown-linux-musl.tar.gz
mv sccache-dist-v0.8.0-x86_64-unknown-linux-musl/sccache-dist /usr/local/bin/sccache
rm -rf sccache-dist-v0.8.0-x86_64-unknown-linux-musl
# This configures Rust to use sccache.
export RUSTC_WRAPPER="/usr/local/bin/sccache"
# You should disable incremental compilation when using sccache
export CARGO_INCREMENTAL="0"
# This is the maximum space sccache cache will use on disk.
export SCCACHE_CACHE_SIZE="1G"

...and then when I run cargo test I get:

root@610a4a3cf828:/app# cargo test
error: failed to run `rustc` to learn about target-specific information

Caused by:
  process didn't exit successfully: `/usr/local/bin/sccache /usr/local/rustup/toolchains/1.78.0-x86_64-unknown-linux-gnu/bin/rustc - --crate-name ___ --print=file-names --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro --print=sysroot --print=split-debuginfo --print=crate-name --print=cfg` (exit status: 2)
  --- stderr
  error: unrecognized subcommand '/usr/local/rustup/toolchains/1.78.0-x86_64-unknown-linux-gnu/bin/rustc'

  Usage: sccache <COMMAND>

  For more information, try '--help'.

Of course under that long path there is really rustc:

/usr/local/rustup/toolchains/1.78.0-x86_64-unknown-linux-gnu/bin/rustc --version
rustc 1.78.0 (9b00956e5 2024-04-29)

...and under /usr/local/bin/scache is sccache:

root@610a4a3cf828:/app# /usr/local/bin/sccache  --version
sccache 0.8.0

I feel that I am stuck. I would appreciate any pointers about how I can move forward from here!

[AJIOB]

Hi @gdubicki,

As I can see, you try to use the sscache-dist instead of sccache when downloading.

The dist binary is used only for the distributed compiling (on the few PCs, servers, etc.). Please, configure the local caching at first.

[gdubicki]

Omg, thanks @AJIOB!

I assumed that "dist" here means something like "distribution version" aka "release version".

I was also looking for the x86_64 architecture in the release assets list and the first 20 assets that are shown only include it for the dist package:

It is just slightly misleading...

But, anyway, my problem is solved!