[gentoo-dev] [PATCH v3 1/1] go-module.eclass: new eclass for go modules

[William Hubbs <williamh@gentoo.org>]

This eclass includes the basic settings and src_unpack/pkg_postinst
functions for Go modules.

Signed-off-by: William Hubbs <williamh@gentoo.org>
---
 eclass/go-module.eclass | 178 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 178 insertions(+)
 create mode 100644 eclass/go-module.eclass

diff --git a/eclass/go-module.eclass b/eclass/go-module.eclass
new file mode 100644
index 00000000000..84f707d8068
--- /dev/null
+++ b/eclass/go-module.eclass
@@ -0,0 +1,178 @@
+# Copyright 2019 Gentoo authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: go-module.eclass
+# @MAINTAINER:
+# William Hubbs <williamh@gentoo.org>
+# @SUPPORTED_EAPIS: 7
+# @BLURB: basic eclass for building software written as go modules
+# @DESCRIPTION:
+# This eclass provides basic settings and functions
+# needed by all software written in the go programming language that uses
+# go modules.
+#
+# You will know the software you are packaging uses modules because
+# it will have files named go.sum and go.mod in its top-level source
+# directory. If it does not have these files, use the golang-* eclasses.
+#
+# If it has these files and a directory named vendor in its top-level
+# source directory, you only need to inherit the eclass since upstream
+# is vendoring the dependencies.
+#
+# If it does not have a vendor directory, you should use the EGO_VENDOR
+# variable and the go-module_vendor_uris function as shown in the
+# example below to handle dependencies.
+#
+# Since Go programs are statically linked, it is important that your ebuild's
+# LICENSE= setting includes the licenses of all statically linked
+# dependencies. So please make sure it is accurate.
+#
+# @EXAMPLE:
+#
+# @CODE
+#
+# inherit go-module
+#
+# EGO_VENDOR=(
+#	"github.com/xenolf/lego 6cac0ea7d8b28c889f709ec7fa92e92b82f490dd"
+# "golang.org/x/crypto 453249f01cfeb54c3d549ddb75ff152ca243f9d8 github.com/golang/crypto"
+# )
+#
+# SRC_URI="https://github.com/example/${PN}/archive/v${PV}.tar.gz -> ${P}.tar.gz
+# $(go-module_vendor_uris)"
+#
+# @CODE
+
+case ${EAPI:-0} in
+	7) ;;
+	*) die "${ECLASS} API in EAPI ${EAPI} not yet established."
+esac
+
+if [[ -z ${_GO_MODULE} ]]; then
+
+_GO_MODULE=1
+
+BDEPEND=">=dev-lang/go-1.12"
+
+# Force go to build in module mode.
+# In this mode the GOPATH environment variable is ignored.
+# this will become the default in the future.
+export GO111MODULE=on
+
+# The following go flags should be used for all builds.
+# -mod=vendor stopps downloading of dependencies from the internet.
+# -v prints the names of packages as they are compiled
+# -x prints commands as they are executed
+export GOFLAGS="-mod=vendor -v -x"
+
+# Do not complain about CFLAGS etc since go projects do not use them.
+QA_FLAGS_IGNORED='.*'
+
+# Go packages should not be stripped with strip(1).
+RESTRICT="strip"
+
+EXPORT_FUNCTIONS src_unpack pkg_postinst
+
+# @ECLASS-VARIABLE: EGO_VENDOR
+# @DESCRIPTION:
+# This variable contains a list of vendored packages.
+# The items of this array are strings that contain the
+# import path and the git commit hash for a vendored package.
+# If the import path does not start with github.com, the third argument
+# can be used to point to a github repository.
+
+# @FUNCTION: go-module_vendor_uris
+# @DESCRIPTION:
+# Convert the information in EGO_VENDOR to a format suitable for
+# SRC_URI.
+# A call to this function should be added to SRC_URI in your ebuild if
+# the upstream package does not include vendored dependencies.
+go-module_vendor_uris() {
+	local hash import line repo x
+	for line in "${EGO_VENDOR[@]}"; do
+		read -r import hash repo x <<< "${line}"
+		if [[ -n $x ]]; then
+			eerror "Trailing information in EGO_VENDOR in ${P}.ebuild"
+			eerror "${line}"
+			eerror "Trailing information is: \"$x\""
+			die "Invalid EGO_VENDOR format"
+		fi
+		: "${repo:=${import}}"
+		echo "https://${repo}/archive/${hash}.tar.gz -> ${repo//\//-}-${hash}.tar.gz"
+	done
+}
+
+# @FUNCTION: go-module_src_unpack
+# @DESCRIPTION:
+# Extract all archives in ${a} which are not nentioned in ${EGO_VENDOR}
+# to their usual locations then extract all archives mentioned in
+# ${EGO_VENDOR} to ${S}/vendor.
+go-module_src_unpack() {
+	debug-print-function ${FUNCNAME} "$@"
+	local f hash import line repo tarball vendor_tarballs x
+	vendor_tarballs=()
+	for line in "${EGO_VENDOR[@]}"; do
+		read -r import hash repo x <<< "${line}"
+		if [[ -n $x ]]; then
+			eerror "Trailing information in EGO_VENDOR in ${P}.ebuild"
+			eerror "${line}"
+			die "Invalid EGO_VENDOR format"
+		fi
+		: "${repo:=${import}}"
+		tarball=${repo//\//-}-${hash}.tar.gz
+		vendor_tarballs+=("${tarball}")
+	done
+	for f in $A; do
+		[[ -n ${vendor_tarballs[*]} ]] && has $f ${vendor_tarballs[@]} &&
+			continue
+		unpack $f
+	done
+
+	[[ -z ${vendor_tarballs[*]} ]] && return
+	for line in "${EGO_VENDOR[@]}"; do
+		read -r import hash repo _ <<< "${line}"
+		: "${repo:=${import}}"
+		tarball=${repo//\//-}-${hash}.tar.gz
+		ebegin "Vendoring ${import} ${tarball}"
+		rm -fr "${S}/vendor/${import}" || die
+		mkdir -p "${S}/vendor/${import}" || die
+		tar -C "${S}/vendor/${import}" -x --strip-components 1 \
+			-f "${DISTDIR}/${tarball}" || die
+		eend
+	done
+}
+
+# @FUNCTION: go-module_live_vendor
+# @DESCRIPTION:
+# This function is used in live ebuilds to vendor the dependencies when
+# upstream doesn't vendor them.
+go-module_live_vendor() {
+	debug-print-function ${FUNCNAME} "$@"
+
+	has live ${PROPERTIES} ||
+		die "${FUNCNAME} only allowed in live ebuilds"
+	[[ "${EBUILD_PHASE}" == unpack ]] ||
+		die "${FUNCNAME} only allowed in src_unpack"
+	[[ -d "${S}"/vendor ]] ||
+		die "${FUNCNAME} only allowed when upstream isn't vendoring"
+
+	pushd "${S}" >& /dev/null || die
+	go mod vendor || die
+	popd >& /dev/null || die
+}
+
+# @FUNCTION: go-module_pkg_postinst
+# @DESCRIPTION:
+# Display a warning about security updates for Go programs.
+go-module_pkg_postinst() {
+	debug-print-function ${FUNCNAME} "$@"
+	ewarn "${PN} is written in the Go programming language."
+	ewarn "Since this language is statically linked, security"
+	ewarn "updates will be handled in individual packages and will be"
+	ewarn "difficult for us to track as a distribution."
+	ewarn "For this reason, please update any go packages asap when new"
+	ewarn "versions enter the tree or go stable if you are running the"
+	ewarn "stable tree."
+}
+
+fi
-- 
2.21.0