Is there an scriptable way to get the final binary which cargo run uses?

[fogti]

I want to run the program built by cargo build [--release] in a loop, but I haven't found a way to get the path the produced binary "programmatically" (e.g. automatable).
I have multiple developing machines with differing target-dir's, thus, on some machines, the target dir would be ./target/, but on others it would be /mnt/path/to/target.x64/ or something like that, which makes the easier approach (just using target/release/$binname) unusable. Running cargo run [--release] in a loop is currently not a good solution because each call introduces an overhead and additional output which is (at least) annoying.

• Is there already a way to get the produced binary path "programmatically"?
• Or a way to prevent cargo run from trying to rebuild the program every time + suppress the Finished message?

[fogti]

Usage example for "easier approach": https://github.com/zserik/crulz-rs/blob/827b7b76a58c381d500da079330f0707957c892b/run_examples.sh

[ehuss]

cargo run --message-format=json will emit "compiler-artifact" messages with the path to the binary (docs).

Alternatively, you can run cargo metadata and look at the "target_directory" field to know which target directory is used. You can also scan the packages binary targets if you don't know the names. docs

#3670 tracks some ideas for future enhancements.

[fogti]

Ok. Is this (cargo metadata) documented somewhere? I think it should be mentioned in the .cargo/config page linked above.

[fogti]

@ehuss Thanks.

[fogti]

for future reference, working version using cargo metadata: https://github.com/fogti/crulz-rs/blob/a8b9c124e1ac5d878f563a17b416fa326167eae0/run_examples.sh

[hoijui]

The previous link gives us the output ("target") directory. If you know the binary name, you can manually append it to that path like it is done there. if not, you can get the binary name from cargo metadata too, as explained here:
https://users.rust-lang.org/t/what-is-the-best-way-to-get-the-name-of-the-binary-that-cargo-will-produce/17907/4

combined:

TARGET_DIR="$(cargo metadata --format-version 1 --no-deps | jq -r '.target_directory')"
BIN_NAME="$(cargo metadata --format-version 1 --no-deps | jq -r '.packages[].targets[] | select( .kind | map(. == "bin") | any ) | .name')"
BINARY_PATH="$TARGET_DIR/release/$BIN_NAME"

[wr7]

For anyone else that finds this on google, here's a script that directly uses the output from cargo build:

#!/bin/sh

json=$(cargo build --message-format=json-render-diagnostics "$@") && \
printf "%s" "$json" | jq -js '[.[] | select(.reason == "compiler-artifact") | select(.executable != null)] | last | .executable'

Additional arguments for cargo build are forwarded from the script's arguments.