new file mode 100644
@@ -0,0 +1,200 @@
+#
+# Copyright 2023 (C) Weidmueller GmbH & Co KG
+# Author: Lukas Funke <lukas.funke@weidmueller.com>
+#
+# Handle Go vendor support for offline builds
+#
+# When importing Go modules, Go downloads the imported modules using
+# a network (proxy) connection ahead of the compile stage. This contradicts
+# the yocto build concept of fetching every source ahead of build-time
+# and supporting offline builds.
+#
+# To support offline builds, we use Go 'vendoring': module dependencies are
+# downloaded during the fetch-phase and unpacked into the modules 'vendor'
+# folder. Additionally a manifest file is generated for the 'vendor' folder
+#
+
+inherit go-mod
+
+def go_src_uri(repo, version, path=None, subdir=None, \
+ vcs='git', replaces=None, pathmajor=None):
+
+ destsuffix = "git/src/import/vendor.fetch"
+ module_path = repo if not path else path
+
+ src_uri = "{}://{};name={}".format(vcs, repo, module_path.replace('/', '.'))
+ src_uri += ";destsuffix={}/{}@{}".format(destsuffix, repo, version)
+
+ if vcs == "git":
+ src_uri += ";nobranch=1;protocol=https"
+
+ src_uri += ";go_module_path={}".format(module_path)
+
+ if replaces:
+ src_uri += ";go_module_replacement={}".format(replaces)
+ if subdir:
+ src_uri += ";go_subdir={}".format(subdir)
+ if pathmajor:
+ src_uri += ";go_pathmajor={}".format(pathmajor)
+ src_uri += ";is_go_dependency=1"
+
+ return src_uri
+
+python do_vendor_unlink() {
+
+ # We unlink
+
+ go_import = d.getVar('GO_IMPORT')
+ source_dir = d.getVar('S')
+ linkname = os.path.join(source_dir, *['src', go_import, 'vendor'])
+
+ os.unlink(linkname)
+}
+
+addtask vendor_unlink before do_install after do_compile
+
+python do_go_vendor() {
+ import shutil
+
+ src_uri = (d.getVar('SRC_URI') or "").split()
+
+ if len(src_uri) == 0:
+ bb.error("SRC_URI is empty")
+ return
+
+ default_destsuffix = "git/src/import/vendor.fetch"
+ fetcher = bb.fetch2.Fetch(src_uri, d)
+ go_import = d.getVar('GO_IMPORT')
+ source_dir = d.getVar('S')
+
+ linkname = os.path.join(source_dir, *['src', go_import, 'vendor'])
+ vendor_dir = os.path.join(source_dir, *['src', 'import', 'vendor'])
+ import_dir = os.path.join(source_dir, *['src', 'import', 'vendor.fetch'])
+
+ if os.path.exists(vendor_dir):
+ # Nothing to do except re-establish link to actual vendor folder
+ if not os.path.exists(linkname):
+ os.symlink(vendor_dir, linkname)
+ return
+
+ bb.utils.mkdirhier(vendor_dir)
+
+ modules = {}
+
+ for url in fetcher.urls:
+ srcuri = fetcher.ud[url].host + fetcher.ud[url].path
+
+ # Skip non Go module src uris
+ if not fetcher.ud[url].parm.get('is_go_dependency'):
+ continue
+
+ destsuffix = fetcher.ud[url].parm.get('destsuffix')
+ # We derive the module repo / version in the following manner (exmaple):
+ #
+ # destsuffix = git/src/import/vendor.fetch/github.com/foo/bar@v1.2.3
+ # p = github.com/foo/bar@v1.2.3
+ # repo = github.com/foo/bar
+ # version = v1.2.3
+
+ p = destsuffix[len(default_destsuffix)+1:]
+ repo, version = p.split('@')
+
+ module_path = fetcher.ud[url].parm.get('go_module_path')
+
+ subdir = fetcher.ud[url].parm.get('go_subdir')
+ subdir = None if not subdir else subdir
+
+ pathMajor = fetcher.ud[url].parm.get('go_pathmajor')
+ pathMajor = None if not pathMajor else pathMajor.strip('/')
+
+ if not repo in modules:
+ modules[repo] = { "version": version,
+ "repo_path": os.path.join(import_dir, p),
+ "module_path": module_path,
+ "subdir": subdir,
+ "pathMajor": pathMajor }
+
+ for module_key in sorted(modules):
+
+ # only take the version which is explicitly listed
+ # as a dependency in the go.mod
+ module = modules[module_key]
+ module_path = module['module_path']
+ rootdir = module['repo_path']
+ subdir = module['subdir']
+ pathMajor = module['pathMajor']
+
+ src = rootdir
+
+ if subdir:
+ src = os.path.join(rootdir, subdir)
+
+ # If the module is released at major version 2 or higher, the module
+ # path must end with a major version suffix like /v2.
+ # This may or may not be part of the subdirectory name
+ #
+ # https://go.dev/ref/mod#modules-overview
+ if pathMajor:
+ tmp = os.path.join(src, pathMajor)
+ # source directory including major version path may or may not exist
+ if os.path.exists(tmp):
+ src = tmp
+
+ dst = os.path.join(vendor_dir, module_path)
+
+ bb.debug(1, "cp %s --> %s" % (src, dst))
+ shutil.copytree(src, dst, symlinks=True, \
+ ignore=shutil.ignore_patterns(".git", \
+ "vendor", \
+ "*._test.go"))
+
+ # If the root directory has a LICENSE file but not the subdir
+ # we copy the root license to the sub module since the license
+ # applies to all modules in the repository
+ # see https://go.dev/ref/mod#vcs-license
+ if subdir:
+ rootdirLicese = os.path.join(rootdir, "LICENSE")
+ subdirLicense = os.path.join(src, "LICENSE")
+
+ if not os.path.exists(subdir) and \
+ os.path.exists(rootdirLicese):
+ shutil.copy2(rootdirLicese, subdirLicense)
+
+ # Copy vendor manifest
+ modules_txt_src = os.path.join(d.getVar('WORKDIR'), "modules.txt")
+ bb.debug(1, "cp %s --> %s" % (modules_txt_src, vendor_dir))
+ shutil.copy2(modules_txt_src, vendor_dir)
+
+ # Clean up vendor dir
+ # We only require the modules in the modules_txt file
+ fetched_paths = set([os.path.relpath(x[0], vendor_dir) for x in os.walk(vendor_dir)])
+
+ # Remove toplevel dir
+ fetched_paths.remove('.')
+
+ vendored_paths = set()
+ with open(modules_txt_src) as f:
+ for line in f:
+ if not line.startswith("#"):
+ line = line.strip()
+ vendored_paths.add(line)
+
+ # Add toplevel dirs into vendored dir, as we want to keep them
+ topdir = os.path.dirname(line)
+ while len(topdir):
+ if not topdir in vendored_paths:
+ vendored_paths.add(topdir)
+
+ topdir = os.path.dirname(topdir)
+
+ for path in fetched_paths:
+ if path not in vendored_paths:
+ realpath = os.path.join(vendor_dir, path)
+ if os.path.exists(realpath):
+ shutil.rmtree(realpath)
+
+ # Create a symlink the the actual directory
+ os.symlink(vendor_dir, linkname)
+}
+
+addtask go_vendor before do_patch after do_unpack