From 625ff838cb6490fa9cffa66491c09f51eadbff7f Mon Sep 17 00:00:00 2001
From: Benjamin Gilbert <bgilbert@redhat.com>
Date: Fri, 9 Apr 2021 17:46:27 -0400
Subject: [PATCH] Add go-mods-to-bundled-provides.py

---
 go-mods-to-bundled-provides.py | 84 ++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100755 go-mods-to-bundled-provides.py

diff --git a/go-mods-to-bundled-provides.py b/go-mods-to-bundled-provides.py
new file mode 100755
index 0000000..3de621a
--- /dev/null
+++ b/go-mods-to-bundled-provides.py
@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+
+'''
+    Tiny dumb script that generates virtual bundled `Provides` from a repo that
+    uses go modules and vendoring.
+'''
+
+import sys
+import re
+
+
+def main():
+    repos = get_repos_from_go_mod()
+    print_provides_from_modules_txt(repos)
+
+
+def get_repos_from_go_mod():
+    repos = {}
+    in_reqs = False
+    for line in open('go.mod'):
+        line = line.strip()
+        if in_reqs and line.startswith(')'):
+            break
+        if not in_reqs:
+            if line.startswith('require ('):
+                in_reqs = True
+            continue
+        req = line.split()
+
+        repo = req[0]
+        tag = req[1]
+
+        repos[repo] = go_mod_tag_to_rpm_provides_version(tag)
+
+    return repos
+
+
+def go_mod_tag_to_rpm_provides_version(tag):
+
+    # go.mod tags are either exact git tags, or may be "pseudo-versions". We
+    # want to convert these tags to something resembling a version string that
+    # RPM won't fail on. For more information, see
+    # https://golang.org/cmd/go/#hdr-Pseudo_versions and following sections.
+
+    # trim off any +incompatible
+    if tag.endswith('+incompatible'):
+        tag = tag[:-len('+incompatible')]
+
+    # git tags are normally of the form v$VERSION
+    if tag.startswith('v'):
+        tag = tag[1:]
+
+    # is this a pseudo-version? e.g. v0.0.0-20181031085051-9002847aa142
+    m = re.match("(.*)-([0-9]{14})-([a-f0-9]{12})", tag)
+    if m:
+        # rpm doesn't like multiple dashes in the version, so just merge the
+        # timestamp and the commit checksum into the "release" field
+        tag = f"{m.group(1)}-{m.group(2)}.git{m.group(3)}"
+
+    return tag
+
+
+def print_provides_from_modules_txt(repos):
+
+    for line in open('vendor/modules.txt'):
+        if line.startswith('#'):
+            continue
+        gopkg = line.strip()
+        repo = lookup_repo_for_pkg(repos, gopkg)
+        if not repo:
+            # must be a pkg for tests only; ignore
+            continue
+        tag = repos[repo]
+        print(f"Provides: bundled(golang({gopkg})) = {tag}")
+
+
+def lookup_repo_for_pkg(repos, gopkg):
+    for repo in repos:
+        if gopkg.startswith(repo):
+            return repo
+
+
+if __name__ == '__main__':
+    sys.exit(main())