Debian packages from Cargo projects

This is a Cargo helper command which automatically creates binary Debian packages (.deb) from Cargo projects.

Installation

rustup update   # Debian's Rust is too outdated, use rustup.rs
cargo install cargo-deb

Requires Rust 1.71+, and optionally dpkg, dpkg-dev and liblzma-dev. Compatible with Ubuntu. If the LZMA dependency causes you headaches, try cargo install cargo-deb --no-default-features.

If you get a compilation error, run rustup update! If you get an error running rustup update, uninstall your rust/cargo package, and install the official Rust instead.

Usage

cargo deb

Upon running cargo deb from the base directory of your Rust project, the Debian package will be created in target/debian/<project_name>_<version>-1_<arch>.deb (or you can change the location with the --output option). This package can be installed with dpkg -i target/debian/*.deb.

cargo deb --install builds and installs the project system-wide.

Configuration

No configuration is necessary to make a basic package from a Cargo project with a binary. This command obtains basic information it needs from the Cargo.toml file. It uses Cargo fields: name, version, license, license-file, description, readme, and homepage or repository.

For a more complete Debian package, you may also define a new table, [package.metadata.deb] that contains maintainer, copyright, license-file, changelog, depends, conflicts, breaks, replaces, provides, extended-description/extended-description-file, section, priority, and assets.

For a Debian package that includes one or more systemd unit files you may also wish to define a new (inline) table, [package.metadata.deb.systemd-units], so that the unit files are automatically added as assets and the units are properly installed. Systemd integration

Debug symbols

Debug symbols are stripped from built binaries by default, unless [profile.release] debug = true is set in Cargo.toml. If cargo deb --separate-debug-symbols is run, the debug symbols will be packaged as a separate file installed at /usr/lib/debug/<build-id-or-path>.debug. This can also be enabled via [package.metadata.deb] under separate-debug-symbols.

[package.metadata.deb] options

Everything is optional:

• name: The name of the Debian package. If not present, the name of the crate is used.
• maintainer: The person maintaining the Debian packaging. If not present, the first author is used. Can be set via --maintainer on the command line.
• copyright: To whom and when the copyright of the software is granted. If not present, the list of authors is used.
• license-file: 2-element array with a location of the license file and the amount of lines to skip at the top. If not present, package-level license-file is used.
• depends: The runtime dependencies of the project. Generated automatically when absent, or if the list includes the $auto keyword.
• pre-depends: The pre-dependencies of the project. This will be empty by default.
• recommends: The recommended dependencies of the project. This will be empty by default.
• suggests: The suggested dependencies of the project. This will be empty by default.
• enhances: A list of packages this package can enhance. This will be empty by default.
• conflicts, breaks, replaces, provides — package transition control.
• extended-description: An extended description of the project — the more detailed the better. Either extended-description-file (see below) or package's readme file is used if it is not provided.
• extended-description-file: A file with extended description of the project. When specified, used if extended-description is not provided.
• revision: An additional version of the Debian package (when the package is updated more often than the project). It defaults to "1", but can be set to an empty string to omit the revision. Can be set via --deb-revision on the command line.
• section: The application category that the software belongs to.
• priority: Defines if the package is required or optional.
• assets: Files to be included in the package and the permissions to assign them. If assets are not specified, then defaults are taken from binaries listed in [[bin]] (copied to /usr/bin/) and package readme (copied to usr/share/doc/…).
  1. source: the first argument of each asset is the location of that asset in the Rust project. Glob patterns are allowed. You can use target/release/ in asset paths, even if Cargo is configured to cross-compile or use custom CARGO_TARGET_DIR. The target dir paths will be automatically corrected.
  2. dest: the second argument is where the file will be copied.
     • If is argument ends with / it will be inferred that the target is the directory where the file will be copied.
     • Otherwise, it will be inferred that the source argument will be renamed when copied.
  3. mode: the third argument is the permissions (octal string) to assign that file.
• merge-assets: See "Merging Assets" section under "Advanced Usage"
• maintainer-scripts: directory containing templates, preinst, postinst, prerm, or postrm scripts.
• conf-files: List of configuration files that the package management system will not overwrite when the package is upgraded.
• triggers-file: Path to triggers control file for use by the dpkg trigger facility.
• changelog: Path to Debian-formatted changelog file.
• features: List of Cargo features to use when building the package.
• default-features: whether to use default crate features in addition to the features list (default true).
• separate-debug-symbols: whether to keep debug symbols, but strip them from executables and save them in separate files (default false). If it is enabled, then cargo deb --no-separate-debug-symbols can be used to suppress extraction of the debug symbols.
• preserve-symlinks: Whether to preserve symlinks in the asset files (default false).
• systemd-units: Optional configuration settings for automated installation of systemd units.
• conf-files: List of absolute paths of config files outside /etc ["/not-etc/app/config"]. You still need to list the files in assets to have them packaged.

Example of custom Cargo.toml additions

[package.metadata.deb]
maintainer = "Michael Aaron Murphy <mmstickman@gmail.com>"
copyright = "2017, Michael Aaron Murphy <mmstickman@gmail.com>"
license-file = ["LICENSE", "4"]
extended-description = """\
A simple subcommand for the Cargo package manager for \
building Debian packages from Rust projects."""
depends = "$auto"
section = "utility"
priority = "optional"
assets = [
    # both syntaxes are equivalent:
    ["target/release/cargo-deb", "usr/bin/", "755"],
    { source = "README.md", dest = "usr/share/doc/cargo-deb/README", mode = "644"},
]

Advanced usage

Debian packages can use a number of different compression formats, but the target system may only support some of them. The default format is currently xz, but this may change at any point to support newer formats. The format can be explicitly specified using the --compress-type command-line option. The supported formats are "gzip" and "xz".

--fast flag uses lighter compression. Useful for very large packages or quick deployment.

--compress-system forces the use of system command-line tools for data compression.

[package.metadata.deb.variants.$name]

There can be multiple variants of the metadata in one Cargo.toml file. --variant=name selects the variant to use. Options set in a variant override [package.metadata.deb] options. It automatically adjusts the package name.

Merging Assets

When defining a variant it can be useful to also define different assets. If the merge-assets option is used, cargo-deb will merge the list of assets provided to the option with the parent asset list. There are three merging strategies, append, by.dest, and by.src.

• merge-assets.append: Appends this list of assets to the parent list of assets.
• merge-assets.by.dest: Merges this list of assets to the parent list of assets, joining on the destination path. Will replace both the source path and permissions.
• merge-assets.by.src: Merges this list of assets to the parent list of assets, joining on the source path. Will replace both the destination path and permissions.

Note: Using both append, and a by.* option are allowed, w/ the former being applied before the latter.

Example of merge-assets

# Example parent asset list
[package.metadata.deb]
assets = [
    # binary
    ["target/release/example", "usr/bin/", "755"],
    # assets
    ["assets/*", "var/lib/example", "644"],
    ["target/release/assets/*", "var/lib/example", "644"],
    ["3.txt", "var/lib/example/3.txt", "644"],
    ["3.txt", "var/lib/example/merged.txt", "644"],
]

# Example merging by appending asset list
[package.metadata.deb.variants.mergeappend]
merge-assets.append = [
    ["4.txt", "var/lib/example/appended/4.txt", "644"]
]

# Example merging by `dest` path
[package.metadata.deb.variants.mergedest]
merge-assets.by.dest = [
    ["4.txt", "var/lib/example/merged.txt", "644"]
]

# Example merging by `src` path
[package.metadata.deb.variants.mergesrc]
merge-assets.by.src = [
    ["3.txt", "var/lib/example/merged-2.txt", "644"]
]

# Example merging by appending and by `src` path
[package.metadata.deb.variants.mergeappendandsrc]
merge-assets.append = [
    ["4.txt", "var/lib/example/appended/4.txt", "644"]
]
merge-assets.by.src = [
    ["3.txt", "var/lib/example/merged-2.txt", "644"]
]

[package.metadata.deb.systemd-units]

See systemd integration.

Cross-compilation

cargo deb supports cross-compilation. It can be run from any unix-like host, including macOS, provided that the build environment is set up for cross-compilation:

• The cross-compilation target has to be installed via rustup (e.g. rustup target add i686-unknown-linux-gnu) and has to be installed for the host system (e.g. apt-get install libc6-dev-i386). Note that Rust's and Debian's architecture names are different. See rustc --print target-list for the list of supported values for the --target argument.
• A Linux-compatible linker and system libraries (e.g. glibc or musl) must be installed and available to Rust/Cargo,
  • dpkg --add-architecture <debian architecture name>
  • apt-get install pkg-config build-essential crossbuild-essential-<debian architecture name>
• Cargo must be configured to use a cross-linker.
• Cargo dependencies that use C libraries probably won't work, unless you install a target's sysroot for pkg-config. Setting PKG_CONFIG_ALLOW_CROSS=1 will not help at all, and will only make things worse.
  • apt-get install libssl-dev:<debian architecture name>
• Cargo dependencies that build C code probably won't work, unless you install a C compiler for the target system, and configure appropriate CC_<target> variables.
  • export HOST_CC=gcc
  • export CC_x86_64_unknown_linux_gnu=/usr/bin/x86_64-linux-gnu-gcc (correct the target and paths for your OS)
• Stripping probably won't work, unless you install versions compatible with the target and configure their paths in .cargo/config by adding [target.<target triple>] strip = { path = "…" } objcopy = { path = "…" }. Alternatively, use --no-strip.

Yes, these requirements are onerous. You can also try cross or cargo zigbuild, since Zig is way better at cross-compiling, and then run cargo deb --target=… --no-build.

cargo deb --target=i686-unknown-linux-gnu

Cross-compiled archives are saved in target/<target triple>/debian/*.deb. The actual archive path is printed on success.

Note that you can't use cross-compilation to build for an older version of Debian. If you need to support Debian releases older than the host, consider using a container or a VM, or make a completely static binary for MUSL instead.

Separate debug info

To get debug symbols, set in Cargo.toml:

[profile.release]
debug = true
# or debug="line-tables-only" for smaller files

Note: building using the dev profile is intentionally unsupported.

cargo deb --separate-debug-symbols --compress-debug-symbols

Removes debug symbols from the executables, and places them in separate files in /usr/lib/debug/.build-id/*. Requires GNU objcopy tool. --compress-debug-symbols uses zstd, and requires objcopy to support it.

Custom build flags

If you would like to handle the build process yourself, you can use cargo deb --no-build so that the cargo-deb command will not attempt to rebuild your project.

cargo deb -- <cargo build flags>

Flags after -- are passed to cargo build, so you can use options such as -Z, --frozen, and --locked. Please use that only for features that cargo-deb doesn't support natively.

Workspaces

Cargo-deb understands workspaces and can build all crates in the workspace if necessary. However, you must choose one crate to be the source of the package metadata. You can select which crate to build with -p crate_name or --manifest-path=<path/to/Cargo.toml>.

Custom version strings

cargo deb --deb-version 1.my-custom-version

Overrides the version string generated from the Cargo manifest, including revision. Alternatively, --deb-revision can be used to change only the suffix.

Troubleshooting

For maximum logging, use:

RUST_LOG=debug cargo deb --verbose

Undefined reference to lzma_stream_encoder_mt error

This happens when the system-provided LZMA library is too old. Try with a bundled version:

cargo install cargo-deb --features=static-lzma

or use the xz command-line tool by setting the --compress-system flag.

[!NOTE] cargo-deb uses the xz2 crate that bundles an old safe version of liblzma 5.2 by the original maintainer, and a simple Cargo-based build script. It is unaffected by the CVE-2024-3094.