buildroot/package/pkg-golang.mk
Christian Stewart 7afd262da0 package/go: implement go modules integration
The Go compiler needs to know the "import path" to the root of package
source repositories. Previously, this was done by creating a fake
_gopath in the build directory and symlinking the package source into
that path.

Go has deprecated the GOPATH mechanism in favor of a new approach -
Modules - which specifies the root import path (and dependencies) in a
"go.mod" file. This commit moves Buildroot to use the new go.mod
approach, which requires:

 - Passing GO111MODULE=on when building host or target Go packages.

 - Passing GOPROXY=off and -mod=vendor to prevent the Go module system
   from downloading by itself sources from the Internet. We currently
   only support Go packages that have all their dependencies in their
   source tree in "vendor" directories.

 - Specifying a <pkg>_GOMOD variable, which is used both to create a
   minimal go.mod file in the package source tree if it exists, and to
   invoke the right build targets. Indeed, all elements in
   <pkg>_BUILD_TARGETS are now relative to <pkg>_GOMOD.

Reference: https://github.com/golang/go/wiki/Modules

Signed-off-by: Christian Stewart <christian@paral.in>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
2020-08-29 14:49:06 +02:00

150 lines
5.0 KiB
Makefile

################################################################################
# Golang package infrastructure
#
# This file implements an infrastructure that eases development of package .mk
# files for Go packages. It should be used for all packages that are written in
# go.
#
# See the Buildroot documentation for details on the usage of this
# infrastructure
#
#
# In terms of implementation, this golang infrastructure requires the .mk file
# to only specify metadata information about the package: name, version,
# download URL, etc.
#
# We still allow the package .mk file to override what the different steps are
# doing, if needed. For example, if <PKG>_BUILD_CMDS is already defined, it is
# used as the list of commands to perform to build the package, instead of the
# default golang behavior. The package can also define some post operation
# hooks.
#
################################################################################
GO_BIN = $(HOST_DIR)/bin/go
################################################################################
# inner-golang-package -- defines how the configuration, compilation and
# installation of a Go package should be done, implements a few hooks to tune
# the build process for Go specificities and calls the generic package
# infrastructure to generate the necessary make targets
#
# argument 1 is the lowercase package name
# argument 2 is the uppercase package name, including a HOST_ prefix for host
# packages
# argument 3 is the uppercase package name, without the HOST_ prefix for host
# packages
# argument 4 is the type (target or host)
#
################################################################################
define inner-golang-package
$(2)_BUILD_OPTS += \
-ldflags "$$($(2)_LDFLAGS)" \
-tags "$$($(2)_TAGS)" \
-trimpath \
-p $(PARALLEL_JOBS)
# Target packages need the Go compiler on the host.
$(2)_DEPENDENCIES += host-go
$(2)_BUILD_TARGETS ?= .
# If the build target is just ".", then we assume the binary to be
# produced is named after the package. If however, a build target has
# been specified, we assume that the binaries to be produced are named
# after each build target building them (below in <pkg>_BUILD_CMDS).
ifeq ($$($(2)_BUILD_TARGETS),.)
$(2)_BIN_NAME ?= $(1)
endif
$(2)_INSTALL_BINS ?= $(1)
# Source files in Go usually use an import path resolved around
# domain/vendor/software. We infer domain/vendor/software from the upstream URL
# of the project.
$(2)_SRC_DOMAIN = $$(call domain,$$($(2)_SITE))
$(2)_SRC_VENDOR = $$(word 1,$$(subst /, ,$$(call notdomain,$$($(2)_SITE))))
$(2)_SRC_SOFTWARE = $$(word 2,$$(subst /, ,$$(call notdomain,$$($(2)_SITE))))
# $(2)_GOMOD is the root Go module path for the project, inferred if not set.
# If the go.mod file does not exist, one is written with this root path.
$(2)_GOMOD ?= $$($(2)_SRC_DOMAIN)/$$($(2)_SRC_VENDOR)/$$($(2)_SRC_SOFTWARE)
# Generate a go.mod file if it doesn't exist. Note: Go is configured
# to use the "vendor" dir and not make network calls.
define $(2)_GEN_GOMOD
if [ ! -f $$(@D)/go.mod ]; then \
printf "module $$($(2)_GOMOD)\n" > $$(@D)/go.mod; \
fi
endef
$(2)_POST_PATCH_HOOKS += $(2)_GEN_GOMOD
# Build step. Only define it if not already defined by the package .mk
# file.
ifndef $(2)_BUILD_CMDS
ifeq ($(4),target)
ifeq ($(BR2_STATIC_LIBS),y)
$(2)_LDFLAGS += -extldflags '-static'
endif
# Build package for target
define $(2)_BUILD_CMDS
$$(foreach d,$$($(2)_BUILD_TARGETS),\
cd $$(@D); \
$$(HOST_GO_TARGET_ENV) \
$$($(2)_GO_ENV) \
$$(GO_BIN) build -v $$($(2)_BUILD_OPTS) \
-o $$(@D)/bin/$$(or $$($(2)_BIN_NAME),$$(notdir $$(d))) \
$$($(2)_GOMOD)/$$(d)
)
endef
else
# Build package for host
define $(2)_BUILD_CMDS
$$(foreach d,$$($(2)_BUILD_TARGETS),\
cd $$(@D); \
$$(HOST_GO_HOST_ENV) \
$$($(2)_GO_ENV) \
$$(GO_BIN) build -v $$($(2)_BUILD_OPTS) \
-o $$(@D)/bin/$$(or $$($(2)_BIN_NAME),$$(notdir $$(d))) \
$$($(2)_GOMOD)/$$(d)
)
endef
endif
endif
# Target installation step. Only define it if not already defined by the
# package .mk file.
ifndef $(2)_INSTALL_TARGET_CMDS
define $(2)_INSTALL_TARGET_CMDS
$$(foreach d,$$($(2)_INSTALL_BINS),\
$(INSTALL) -D -m 0755 $$(@D)/bin/$$(d) $(TARGET_DIR)/usr/bin/$$(d)
)
endef
endif
# Host installation step
ifndef $(2)_INSTALL_CMDS
define $(2)_INSTALL_CMDS
$$(foreach d,$$($(2)_INSTALL_BINS),\
$(INSTALL) -D -m 0755 $$(@D)/bin/$$(d) $(HOST_DIR)/bin/$$(d)
)
endef
endif
# Call the generic package infrastructure to generate the necessary make
# targets
$(call inner-generic-package,$(1),$(2),$(3),$(4))
endef # inner-golang-package
################################################################################
# golang-package -- the target generator macro for Go packages
################################################################################
golang-package = $(call inner-golang-package,$(pkgname),$(call UPPERCASE,$(pkgname)),$(call UPPERCASE,$(pkgname)),target)
host-golang-package = $(call inner-golang-package,host-$(pkgname),$(call UPPERCASE,host-$(pkgname)),$(call UPPERCASE,$(pkgname)),host)