merge-features.py

#!/usr/bin/env python3

importargparse
importjson
importsys


deferror(message):
sys.stderr.write(message)
sys.stderr.write("\n")
sys.exit(1)


definvalid_file(features_file, message):
error(f"Invalid features file '{features_file}': {message}")


defparse_args():
parser=argparse.ArgumentParser(
formatter_class=argparse.RawDescriptionHelpFormatter,
description="""
 Merges the given feature files together into stdout. Each file FILE
 must be given a corresponding PREFIX to prefix the name of each entry
 in its features list, though these could be empty if no prefix is
 required.

 Note that the files and prefixes are treated as an ordered list, ie.
 the first FILE corresponds to the first PREFIX.
 """)

parser.add_argument(
"--file", "-f", action="append", dest="files",
help="path of a file to merge"
 )
parser.add_argument(
"--prefix", "-p", action="append", dest="prefixes",
help="prefix to prepend to the name of each feature"
 )

returnparser.parse_known_args()


defread_features(from_file, add_prefix):
withopen(from_file, "r") asf:
features_dict=json.load(f)

if"features"notinfeatures_dict:
invalid_file(from_file, "missing 'features' key")

features= []
forfeatureinfeatures_dict["features"]:
if"name"notinfeature:
invalid_file(from_file, "missing name in features list")

new_feature= {"name": add_prefix+feature["name"]}

if"value"infeature:
new_feature.update({"value" : feature["value"]})

features.append(new_feature)
returnfeatures


defmain():
 (args, _) =parse_args()

ifnotargs.files:
error("No files to merge were provided")

iflen(args.files) !=len(args.prefixes):
error("Must supply the same number of files and prefixes")

features= []
fori, (f, prefix) inenumerate(zip(args.files, args.prefixes)):
features.extend(read_features(f, prefix))

data= {
"features": features
 }
sys.stdout.write(json.dumps(data, indent=2))


if__name__=='__main__':
main()