monitor: convert to json-seq

Tweak the existing json progress to follow the `application/json-seq`
media type as outlined in rfc7464 [0],[1].

[0] https://datatracker.ietf.org/doc/html/rfc7464
[1] https://en.wikipedia.org/wiki/JSON_streaming#Record_separator-delimited_JSON:wqu

osbuild/main_cli.py

@@ -90,7 +90,7 @@ def parse_arguments(sys_argv: List[str]) -> argparse.Namespace:
     parser.add_argument("--json-mode", metavar="MODE", type=str, default="batch",
                         help=("output mode for JSON format; "
                               "'batch' (default if unspecified) mode prints all the results when the build ends "
-                              "'progress' prints status updates while building with each line being a JSON object"))
+                              "'jsonseq' prints status updates while building with each line being a JSON object"))
     parser.add_argument("--output-directory", metavar="DIRECTORY", type=os.path.abspath,
                         help="directory where result objects are stored")
     parser.add_argument("--inspect", action="store_true",
@@ -170,8 +170,8 @@ def osbuild_cli() -> int:
 
     outfd = sys.stdout.fileno()
     if args.json:
-        if args.json_mode == "progress":
-            monitor = osbuild.monitor.JSONProgressMonitor(outfd, manifest)
+        if args.json_mode == "jsonseq":
+            monitor = osbuild.monitor.JSONSeqMonitor(outfd, manifest)
             monitor.log("start", origin="org.osbuild.main")
         elif args.json_mode == "batch":
             monitor = osbuild.monitor.NullMonitor(outfd)

osbuild/monitor.py

@@ -289,8 +289,8 @@ class LogMonitor(BaseMonitor):
         self.out.write(message)
 
 
-class JSONProgressMonitor(BaseMonitor):
-    """Monitor that prints the log output of modules wrapped in a JSON object with context and progress metadata"""
+class JSONSeqMonitor(BaseMonitor):
+    """Monitor that prints the log output of modules wrapped in json-seq objects with context and progress metadata"""
 
     def __init__(self, fd: int, manifest: osbuild.Manifest):
         super().__init__(fd)
@@ -321,6 +321,8 @@ class JSONProgressMonitor(BaseMonitor):
         if origin is not None:
             self._context.origin = origin
         line = LogLine(message=message, context=self._context, progress=self._progress)
+        # follow rfc7464 (application/json-seq)
+        self.out.write(u"\x1e")
         json.dump(line.as_dict(), self.out)
         self.out.write("\n")
         self._context.origin = oo

test/mod/test_monitor.py

@@ -13,7 +13,7 @@ from collections import defaultdict
 import osbuild
 import osbuild.meta
 from osbuild.monitor import LogMonitor
-from osbuild.monitor import JSONProgressMonitor, Context, Progress, LogLine
+from osbuild.monitor import JSONSeqMonitor, Context, Progress, LogLine
 from osbuild.objectstore import ObjectStore
 from osbuild.pipeline import Runner
 
@@ -195,7 +195,7 @@ def test_json_progress_monitor():
     manifest.add_pipeline(pl2, "", "")
 
     with tempfile.TemporaryFile() as tf:
-        mon = JSONProgressMonitor(tf.fileno(), manifest)
+        mon = JSONSeqMonitor(tf.fileno(), manifest)
         mon.log("test-message-1")
         mon.log("test-message-2", origin="test.origin.override")
         mon.begin(manifest.pipelines["test-pipeline-first"])
@@ -208,7 +208,7 @@ def test_json_progress_monitor():
         mon.log("pipeline 2 message 2")
 
         tf.seek(0)
-        log = tf.read().decode().strip().split("\n")
+        log = tf.read().decode().strip().split(u"\x1e")
 
         assert len(log) == 7
         logitem = json.loads(log[0])