111 lines
3.7 KiB
Plaintext
111 lines
3.7 KiB
Plaintext
|
// -*- mode:doc; -*-
|
||
|
|
// vim: set syntax=asciidoc:
|
||
|
|
|
||
|
|
=== Integration of Cargo-based packages
|
||
|
|
|
||
|
|
Cargo is the package manager for the Rust programming language. It allows the
|
||
|
|
user to build programs or libraries written in Rust, but it also downloads and
|
||
|
|
manages their dependencies, to ensure repeatable builds. Cargo packages are
|
||
|
|
called "crates".
|
||
|
|
|
||
|
|
[[cargo-package-tutorial]]
|
||
|
|
|
||
|
|
==== Cargo-based package's +Config.in+ file
|
||
|
|
|
||
|
|
The +Config.in+ file of Cargo-based package 'foo' should contain:
|
||
|
|
|
||
|
|
---------------------------
|
||
|
|
01: config BR2_PACKAGE_FOO
|
||
|
|
02: bool "foo"
|
||
|
|
03: depends on BR2_PACKAGE_HOST_RUSTC_ARCH_SUPPORTS
|
||
|
|
04: select BR2_PACKAGE_HOST_CARGO
|
||
|
|
05: help
|
||
|
|
06: This is a comment that explains what foo is.
|
||
|
|
07:
|
||
|
|
08: http://foosoftware.org/foo/
|
||
|
|
---------------------------
|
||
|
|
|
||
|
|
==== Cargo-based package's +.mk+ file
|
||
|
|
|
||
|
|
Buildroot does not (yet) provide a dedicated package infrastructure for
|
||
|
|
Cargo-based packages. So, we will explain how to write a +.mk+ file for such a
|
||
|
|
package. Let's start with an example:
|
||
|
|
|
||
|
|
------------------------------
|
||
|
|
01: ################################################################################
|
||
|
|
02: #
|
||
|
|
03: # foo
|
||
|
|
04: #
|
||
|
|
05: ################################################################################
|
||
|
|
06:
|
||
|
|
07: FOO_VERSION = 1.0
|
||
|
|
08: FOO_SOURCE = foo-$(FOO_VERSION).tar.gz
|
||
|
|
09: FOO_SITE = http://www.foosoftware.org/download
|
||
|
|
10: FOO_LICENSE = GPLv3+
|
||
|
|
11: FOO_LICENSE_FILES = COPYING
|
||
|
|
12:
|
||
|
|
13: FOO_DEPENDENCIES = host-cargo
|
||
|
|
14:
|
||
|
|
15: FOO_CARGO_ENV = CARGO_HOME=$(HOST_DIR)/share/cargo
|
||
|
|
16: FOO_CARGO_MODE = $(if $(BR2_ENABLE_DEBUG),debug,release)
|
||
|
|
17:
|
||
|
|
18: FOO_BIN_DIR = target/$(RUST_TARGET_NAME)/$(FOO_CARGO_MODE)
|
||
|
|
19:
|
||
|
|
20: FOO_CARGO_OPTS = \
|
||
|
|
21: --$(FOO_CARGO_MODE) \
|
||
|
|
22: --target=$(RUST_TARGET_NAME) \
|
||
|
|
23: --manifest-path=$(@D)/Cargo.toml
|
||
|
|
24:
|
||
|
|
25: define FOO_BUILD_CMDS
|
||
|
|
26: $(TARGET_MAKE_ENV) $(FOO_CARGO_ENV) \
|
||
|
|
27: cargo build $(FOO_CARGO_OPTS)
|
||
|
|
28: endef
|
||
|
|
29:
|
||
|
|
30: define FOO_INSTALL_TARGET_CMDS
|
||
|
|
31: $(INSTALL) -D -m 0755 $(@D)/$(FOO_BIN_DIR)/foo \
|
||
|
|
32: $(TARGET_DIR)/usr/bin/foo
|
||
|
|
33: endef
|
||
|
|
34:
|
||
|
|
35: $(eval $(generic-package))
|
||
|
|
--------------------------------
|
||
|
|
|
||
|
|
The Makefile starts with the definition of the standard variables for package
|
||
|
|
declaration (lines 7 to 11).
|
||
|
|
|
||
|
|
As seen in line 35, it is based on the
|
||
|
|
xref:generic-package-tutorial[+generic-package+ infrastructure]. So, it defines
|
||
|
|
the variables required by this particular infrastructure, where Cargo is
|
||
|
|
invoked:
|
||
|
|
|
||
|
|
* +FOO_BUILD_CMDS+: Cargo is invoked to perform the build. The options required
|
||
|
|
to configure the cross-compilation of the package are passed via
|
||
|
|
+FOO_CONF_OPTS+.
|
||
|
|
|
||
|
|
* +FOO_INSTALL_TARGET_CMDS+: The binary executable generated is installed on
|
||
|
|
the target.
|
||
|
|
|
||
|
|
In order to have Cargo available for the build, +FOO_DEPENDENCIES+ needs to
|
||
|
|
contain +host-cargo+.
|
||
|
|
|
||
|
|
To sum it up, to add a new Cargo-based package, the Makefile example can be
|
||
|
|
copied verbatim then edited to replace all occurences of +FOO+ with the
|
||
|
|
uppercase name of the new package and update the values of the standard
|
||
|
|
variables.
|
||
|
|
|
||
|
|
==== About Dependencies Management
|
||
|
|
|
||
|
|
A crate can depend on other libraries from crates.io or git repositories, listed
|
||
|
|
in its Cargo.toml file. Before starting a build, Cargo usually downloads
|
||
|
|
automatically them. This step can also be performed independently, via the
|
||
|
|
+cargo fetch+ command.
|
||
|
|
|
||
|
|
Cargo maintains a local cache of the registry index and of git checkouts of the
|
||
|
|
crates, whose location is given by +$CARGO_HOME+. As seen in the package
|
||
|
|
Makefile example at line 15, this environment variable is set to
|
||
|
|
+$(HOST_DIR)/share/cargo+.
|
||
|
|
|
||
|
|
This dependency download mechanism is not convenient when performing an offline
|
||
|
|
build, as Cargo will fail to fetch the dependencies. In that case, it is advised
|
||
|
|
to generate a tarball of the dependencies using the +cargo vendor+ and add it to
|
||
|
|
+FOO_EXTRA_DOWNLOADS+.
|