3 files changed, 196 insertions, 1 deletions

diff --git a/bitbake/lib/bb/fetch2/__init__.py b/bitbake/lib/bb/fetch2/__init__.py
index 5bf2c4b8cf..f84ce59992 100644
--- a/bitbake/lib/bb/fetch2/__init__.py
+++ b/bitbake/lib/bb/fetch2/__init__.py
@@ -1317,7 +1317,7 @@ class FetchData(object):
 
             if checksum_name in self.parm:
                 checksum_expected = self.parm[checksum_name]
-            elif self.type not in ["http", "https", "ftp", "ftps", "sftp", "s3", "az", "crate", "gs"]:
+            elif self.type not in ["http", "https", "ftp", "ftps", "sftp", "s3", "az", "crate", "gs", "gomod"]:
                 checksum_expected = None
             else:
                 checksum_expected = d.getVarFlag("SRC_URI", checksum_name)
@@ -2088,6 +2088,7 @@ from . import npmsw
 from . import az
 from . import crate
 from . import gcp
+from . import gomod
 
 methods.append(local.Local())
 methods.append(wget.Wget())
@@ -2110,3 +2111,4 @@ methods.append(npmsw.NpmShrinkWrap())
 methods.append(az.Az())
 methods.append(crate.Crate())
 methods.append(gcp.GCP())
+methods.append(gomod.GoMod())
diff --git a/bitbake/lib/bb/fetch2/gomod.py b/bitbake/lib/bb/fetch2/gomod.py
new file mode 100644
index 0000000000..fe025e367f
--- /dev/null
+++ b/bitbake/lib/bb/fetch2/gomod.py
@@ -0,0 +1,128 @@
+"""
+BitBake 'Fetch' implementation for Go modules
+
+The gomod fetcher is used to download Go modules to the module cache from a
+module proxy.
+
+Example SRC_URI:
+
+SRC_URI += "gomod://golang.org/x/net;version=v0.9.0;sha256sum=..."
+
+Required SRC_URI parameters:
+
+- version
+    The version of the module.
+
+Optional SRC_URI parameters:
+
+- mod
+    Fetch and unpack the go.mod file only instead of the complete module.
+    The go command may need to download go.mod files for many different modules
+    when computing the build list, and go.mod files are much smaller than
+    module zip files.
+    The default is "0", set mod=1 for the go.mod file only.
+
+- sha256sum
+    The checksum of the module zip file, or the go.mod file in case of fetching
+    only the go.mod file. Alternatively, set the SRC_URI varible flag for
+    "module@version.sha256sum".
+
+Related variables:
+
+- GO_MOD_PROXY
+    The module proxy used by the fetcher.
+
+- GO_MOD_CACHE_DIR
+    The directory where the module cache is located.
+    This must match the exported GOMODCACHE variable for the go command to find
+    the downloaded modules.
+
+See the Go modules reference, https://go.dev/ref/mod, for more information
+about the module cache, module proxies and version control systems.
+"""
+
+import os
+import re
+import shutil
+import zipfile
+
+import bb
+from bb.fetch2 import FetchError
+from bb.fetch2 import MissingParameterError
+from bb.fetch2.wget import Wget
+
+
+def escape(path):
+    """Escape capital letters using exclamation points."""
+    return re.sub(r'([A-Z])', lambda m: '!' + m.group(1).lower(), path)
+
+
+class GoMod(Wget):
+    """Class to fetch Go modules from a Go module proxy via wget"""
+
+    def supports(self, ud, d):
+        """Check to see if a given URL is for this fetcher."""
+        return ud.type == 'gomod'
+
+    def urldata_init(self, ud, d):
+        """Set up to download the module from the module proxy.
+
+        Set up to download the module zip file to the module cache directory
+        and unpack the go.mod file (unless downloading only the go.mod file):
+
+        cache/download/<module>/@v/<version>.zip: The module zip file.
+        cache/download/<module>/@v/<version>.mod: The go.mod file.
+        """
+
+        proxy = d.getVar('GO_MOD_PROXY') or 'proxy.golang.org'
+        moddir = d.getVar('GO_MOD_CACHE_DIR') or 'pkg/mod'
+
+        if 'version' not in ud.parm:
+            raise MissingParameterError('version', ud.url)
+
+        module = ud.host + ud.path
+        ud.parm['module'] = module
+
+        # Set URL and filename for wget download
+        path = escape(module + '/@v/' + ud.parm['version'])
+        if ud.parm.get('mod', '0') == '1':
+            path += '.mod'
+        else:
+            path += '.zip'
+            ud.parm['unpack'] = '0'
+        ud.url = bb.fetch2.encodeurl(
+            ('https', proxy, '/' + path, None, None, None))
+        ud.parm['downloadfilename'] = path
+
+        # Set name parameter if sha256sum is set in recipe
+        name = f"{module}@{ud.parm['version']}"
+        if d.getVarFlag('SRC_URI', name + '.sha256sum'):
+            ud.parm['name'] = name
+
+        # Set subdir for unpack
+        ud.parm['subdir'] = os.path.join(moddir, 'cache/download',
+                                         os.path.dirname(path))
+
+        super().urldata_init(ud, d)
+
+    def unpack(self, ud, rootdir, d):
+        """Unpack the module in the module cache."""
+
+        # Unpack the module zip file or go.mod file
+        super().unpack(ud, rootdir, d)
+
+        if ud.localpath.endswith('.zip'):
+            # Unpack the go.mod file from the zip file
+            module = ud.parm['module']
+            unpackdir = os.path.join(rootdir, ud.parm['subdir'])
+            name = os.path.basename(ud.localpath).rsplit('.', 1)[0] + '.mod'
+            bb.note(f"Unpacking {name} to {unpackdir}/")
+            with zipfile.ZipFile(ud.localpath) as zf:
+                with open(os.path.join(unpackdir, name), mode='wb') as mf:
+                    try:
+                        f = module + '@' + ud.parm['version'] + '/go.mod'
+                        shutil.copyfileobj(zf.open(f), mf)
+                    except KeyError:
+                        # If the module does not have a go.mod file, synthesize
+                        # one containing only a module statement.
+                        mf.write(f'module {module}\n'.encode())
diff --git a/bitbake/lib/bb/tests/fetch.py b/bitbake/lib/bb/tests/fetch.py
index 2ef2063436..2365a50960 100644
--- a/bitbake/lib/bb/tests/fetch.py
+++ b/bitbake/lib/bb/tests/fetch.py
@@ -3390,3 +3390,68 @@ class FetchPremirroronlyBrokenTarball(FetcherTest):
             fetcher.download()
         output = "".join(logs.output)
         self.assertFalse(" not a git repository (or any parent up to mount point /)" in output)
+
+class GoModTest(FetcherTest):
+
+    @skipIfNoNetwork()
+    def test_gomod_url(self):
+        urls = ['gomod://github.com/Azure/azure-sdk-for-go/sdk/storage/azblob;version=v1.0.0;'
+                'sha256sum=9bb69aea32f1d59711701f9562d66432c9c0374205e5009d1d1a62f03fb4fdad']
+
+        fetcher = bb.fetch2.Fetch(urls, self.d)
+        ud = fetcher.ud[urls[0]]
+        self.assertEqual(ud.url, 'https://proxy.golang.org/github.com/%21azure/azure-sdk-for-go/sdk/storage/azblob/%40v/v1.0.0.zip')
+        self.assertNotIn('name', ud.parm)
+
+        fetcher.download()
+        fetcher.unpack(self.unpackdir)
+        downloaddir = os.path.join(self.unpackdir, 'pkg/mod/cache/download')
+        self.assertTrue(os.path.exists(os.path.join(downloaddir, 'github.com/!azure/azure-sdk-for-go/sdk/storage/azblob/@v/v1.0.0.zip')))
+        self.assertTrue(os.path.exists(os.path.join(downloaddir, 'github.com/!azure/azure-sdk-for-go/sdk/storage/azblob/@v/v1.0.0.mod')))
+
+    @skipIfNoNetwork()
+    def test_gomod_url_go_mod_only(self):
+        urls = ['gomod://github.com/Azure/azure-sdk-for-go/sdk/storage/azblob;version=v1.0.0;mod=1;'
+                'sha256sum=7873b8544842329b4f385a3aa6cf82cc2bc8defb41a04fa5291c35fd5900e873']
+
+        fetcher = bb.fetch2.Fetch(urls, self.d)
+        ud = fetcher.ud[urls[0]]
+        self.assertEqual(ud.url, 'https://proxy.golang.org/github.com/%21azure/azure-sdk-for-go/sdk/storage/azblob/%40v/v1.0.0.mod')
+        self.assertNotIn('name', ud.parm)
+
+        fetcher.download()
+        fetcher.unpack(self.unpackdir)
+        downloaddir = os.path.join(self.unpackdir, 'pkg/mod/cache/download')
+        self.assertTrue(os.path.exists(os.path.join(downloaddir, 'github.com/!azure/azure-sdk-for-go/sdk/storage/azblob/@v/v1.0.0.mod')))
+
+    @skipIfNoNetwork()
+    def test_gomod_url_sha256sum_varflag(self):
+        urls = ['gomod://gopkg.in/ini.v1;version=v1.67.0']
+        self.d.setVarFlag('SRC_URI', 'gopkg.in/ini.v1@v1.67.0.sha256sum', 'bd845dfc762a87a56e5a32a07770dc83e86976db7705d7f89c5dbafdc60b06c6')
+
+        fetcher = bb.fetch2.Fetch(urls, self.d)
+        ud = fetcher.ud[urls[0]]
+        self.assertEqual(ud.url, 'https://proxy.golang.org/gopkg.in/ini.v1/%40v/v1.67.0.zip')
+        self.assertEqual(ud.parm['name'], 'gopkg.in/ini.v1@v1.67.0')
+
+        fetcher.download()
+        fetcher.unpack(self.unpackdir)
+        downloaddir = os.path.join(self.unpackdir, 'pkg/mod/cache/download')
+        self.assertTrue(os.path.exists(os.path.join(downloaddir, 'gopkg.in/ini.v1/@v/v1.67.0.zip')))
+        self.assertTrue(os.path.exists(os.path.join(downloaddir, 'gopkg.in/ini.v1/@v/v1.67.0.mod')))
+
+    @skipIfNoNetwork()
+    def test_gomod_url_no_go_mod_in_module(self):
+        urls = ['gomod://gopkg.in/ini.v1;version=v1.67.0;'
+                'sha256sum=bd845dfc762a87a56e5a32a07770dc83e86976db7705d7f89c5dbafdc60b06c6']
+
+        fetcher = bb.fetch2.Fetch(urls, self.d)
+        ud = fetcher.ud[urls[0]]
+        self.assertEqual(ud.url, 'https://proxy.golang.org/gopkg.in/ini.v1/%40v/v1.67.0.zip')
+        self.assertNotIn('name', ud.parm)
+
+        fetcher.download()
+        fetcher.unpack(self.unpackdir)
+        downloaddir = os.path.join(self.unpackdir, 'pkg/mod/cache/download')
+        self.assertTrue(os.path.exists(os.path.join(downloaddir, 'gopkg.in/ini.v1/@v/v1.67.0.zip')))
+        self.assertTrue(os.path.exists(os.path.join(downloaddir, 'gopkg.in/ini.v1/@v/v1.67.0.mod')))