tools: add inline-source.py

Add a simple tool that will spit out a valid org.osbuild.inline
source entry that encodes the given file. Currently always uses
base64 as encoding and sha256 for the hashing.

tools/inline-source.py

@@ -0,0 +1,42 @@
+#!/usr/bin/python3
+"""
+Encode binary file data within the manifest by using
+the org.osbuild.inline source.
+"""
+
+import argparse
+import binascii
+import hashlib
+import json
+import sys
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("FILE", help="The file to encode")
+    args = parser.parse_args()
+
+    with open(args.FILE, "rb") as f:
+        raw = f.read()
+
+    m = hashlib.sha256()
+    m.update(raw)
+    checksum = "sha256:" + m.hexdigest()
+    data = binascii.b2a_base64(raw, newline=False).decode("ascii")
+
+    source = {
+        "org.osbuild.inline": {
+            "items": {
+                checksum: {
+                    "encoding": "base64",
+                    "data": data
+                }
+            }
+        }
+    }
+
+    json.dump(source, sys.stdout, indent=2)
+
+
+if __name__ == "__main__":
+    main()