Using Rust with the Kubos SDK¶
The Kubos SDK comes with pre-built support for Rust and Cargo. Additionally, it includes tooling to assist with cross-compiling for a target OBC and to build projects which use both Rust and C.
Cross-compilation¶
The Kubos SDK provides Rust cross-compilation targets for each of the supported OBCs.
The target name varies depending which command is used to compile the project.
| OBC | cargo build target |
cargo kubos target |
| Beaglebone Black | arm-unknown-linux-gnueabihf | kubos-linux-beaglebone-gcc |
| ISIS-OBC | armv5te-unknown-linux-gnueabi | kubos-linux-isis-gcc |
| Pumpkin MBM2 | arm-unknown-linux-gnueabihf | kubos-linux-pumpkin-mbm2-gcc |
Some Rust crates require that the C compiler be explicitly declared when cross-compiling.
| OBC | Compiler Path |
| Beaglebone Black | /usr/bin/bbb_toolchain/usr/bin/arm-linux-gcc |
| ISIS-OBC | /usr/bin/iobc_toolchain/usr/bin/arm-linux-gcc |
| Pumpkin MBM2 | /usr/bin/bbb_toolchain/usr/bin/arm-linux-gcc |
To simplify development when cross-compiling, use the cargo kubos command to automatically setup
the build environment. The cargo kubos command takes a required cargo sub-command (i.e. build,
test), and a target. For example, to build a project for the ISIS iOBC:
$ cargo kubos -c build -t kubos-linux-isis-gcc
Cross compiling can also be done manually by specifying the C compiler path in the CC
environment variable like so:
$ CC={path} cargo build --target {target}
For example, the equivalent command as above using cargo build:
$ CC=/usr/bin/iobc_toolchain/usr/bin/arm-linux-gcc cargo build --target armv5te-unknown-linux-gnueabi
Some crates also depend on pkg-config, which requires that an additional environment variable,
PKG_CONFIG_ALLOW_CROSS, be set in order to enable cross-compiling:
$ PKG_CONFIG_ALLOW_CROSS=1 CC=/usr/bin/iobc_toolchain/usr/bin/arm-linux-gcc cargo build --target armv5te-unknown-linux-gnueabi
Making Rust Binaries Smaller¶
By default, Rust binaries can be quite large. Check out our Rust optimization tips for suggestions on how to make your compiled Rust projects smaller.
Transferring to Target¶
Rust binaries can be transferred to the target OBC via a supported file transfer method.
Binaries may be transferred to any location on the target board, however, they should be copied to /home/system/usr/bin if you would like them to be automatically accessible via the system PATH.
Running on Target¶
Once transferred, the binary can be started with /path/to/binary-name, or by simply specifying
the binary name if the file was transferred to a system PATH directory.