package: spec file

Provide a spec file for `image-builder-cli`. The spec file is based on
`osbuild-composer`'s spec file except it is simplified as (some)
usecases would currently cloud the intent of the specfile. We can add
back RHEL conditionals when/if we start shipping and building for RHEL.

Some tools from `osbuild-composer` are also included; most notably the
one that generates bundled dependencies from vendored modules.

Signed-off-by: Simon de Vlieger <supakeen@redhat.com>

tools/rpm_spec_vendor2provides

@@ -0,0 +1,63 @@
+#!/usr/bin/python3 -s
+
+# Parse modules.txt files into rpm .spec file Provides for bundled dependencies.
+# Written by Fabio "decathorpe" Valentini <decathorpe@fedoraproject.org> for
+# the fedora syncthing package: https://src.fedoraproject.org/rpms/syncthing
+# SPDX-License-Identifier: CC0-1.0 OR Unlicense
+
+# Modified by @gotmax23 to be used as a dependency generator
+# SPDX-License-Identifier: GPL-3.0-or-later
+# SPDX-FileCopyrightText: 2022 Maxwell G <gotmax@e.email>
+#
+# Minor modifications by Achilleas Koutsou <achilleas@koutsou.net> to be used in
+# the rpm spec file generator for https://github.com/osbuild/osbuild-composer
+
+import re
+import sys
+
+
+def process(path: str):
+    with open(path, encoding="utf-8") as file:
+        contents = file.read()
+
+    lines = contents.split("\n")
+
+    # dependencies = filter lines for "# package version"
+    dependencies = list(filter(lambda line: line.startswith("# "), lines))
+
+    # parse vendored dependencies into (import path, version) pairs
+    vendored = []
+    # Handle => style replace directives
+    replace_regex = re.compile(r"^.+( v[0-9-\.]+)? => ")
+    for dep in dependencies:
+        fields = replace_regex.sub("", dep[2:]).split(" ")
+        if len(fields) == 2:
+            ipath, version = fields
+        elif len(fields) == 1:
+            ipath = fields[0]
+            version = "HEAD"
+        else:
+            raise RuntimeError(f"Failed to parse dependency: {dep}")
+
+        # check for git snapshots
+        if len(version) > 27:
+            # return only 7 digits of git commit hash
+            version = version[-12:-1][0:7]
+        else:
+            # strip off leading "v"
+            version = version.lstrip("v")
+
+        vendored.append((ipath, version))
+
+    for ipath, version in vendored:
+        print(f"Provides: bundled(golang({ipath})) = {version}")
+
+
+def main() -> None:
+    files = sys.argv[1:]
+    for file in files:
+        process(file)
+
+
+if __name__ == "__main__":
+    main()