From 9edeb19ebbfb8a151e6b4f0bafa5d76383431a6f Mon Sep 17 00:00:00 2001
From: Lars Karlitski <lars@karlitski.net>
Date: Wed, 25 Sep 2019 18:25:40 +0200
Subject: [PATCH] osbuild: add --json argument

`osbuild --json [ARGS]` will suppress the normal output and print its
result as JSON. For now, it only does this when it returns 0. Otherwise,
it prints the error from the latest stage.

This is useful for other tools to call it and get machine-readable
output.
---
 osbuild/__main__.py | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/osbuild/__main__.py b/osbuild/__main__.py
index 8b3481b7..0dd6de18 100755
--- a/osbuild/__main__.py
+++ b/osbuild/__main__.py
@@ -21,6 +21,8 @@ def main():
                         help="the directory where intermediary os trees are stored")
     parser.add_argument("-l", "--libdir", metavar="DIRECTORY", type=os.path.abspath,
                         help="the directory containing stages, assemblers, and the osbuild library")
+    parser.add_argument("--json", action="store_true",
+                        help="output results in JSON format")
     requiredNamed = parser.add_argument_group('required named arguments')
     requiredNamed.add_argument("-o", "--output", dest="output_dir", metavar="DIRECTORY", type=os.path.abspath,
                                help="provide the empty DIRECTORY as output argument to the last stage", required=True)
@@ -35,16 +37,27 @@ def main():
         pipeline.prepend_build_pipeline(build)
 
     try:
-        pipeline.run(args.output_dir, args.store, interactive=True, libdir=args.libdir)
+        pipeline.run(args.output_dir, args.store, interactive=not args.json, libdir=args.libdir)
     except KeyboardInterrupt:
         print()
         print(f"{RESET}{BOLD}{RED}Aborted{RESET}")
-        sys.exit(130)
+        return 130
     except (osbuild.StageFailed, osbuild.AssemblerFailed) as error:
         print()
         print(f"{RESET}{BOLD}{RED}{error.name} failed with code {error.returncode}{RESET}")
-        sys.exit(1)
+        if args.json:
+            print(error.output)
+        return 1
+
+    if args.json:
+        json.dump({
+            "tree_id": pipeline.tree_id,
+            "output_id": pipeline.output_id,
+        }, sys.stdout)
+        sys.stdout.write("\n")
+
+    return 0
 
 
 if __name__ == "__main__":
-    main()
+    sys.exit(main())