monitor: refactor class LogLine to log_entry()

The class LogLine() is purely used as a dataclass with no state
and the only function on it is `as_dict()`. This got refactored
into a new function `log_entry()` because there is no need for
this to be a class. The function that takes the same inputs.

osbuild/monitor.py

@@ -149,31 +149,21 @@ class Progress:
         return d
 
 
-class LogLine:
-    """A single JSON serializable log line
-
-    Create a single log line with a given message, error message, context, and progress objects.
-    All arguments are optional. A timestamp is added to the dictionary when calling the 'as_dict()' method.
+def log_entry(message: Optional[str] = None,
+              context: Optional[Context] = None,
+              progress: Optional[Progress] = None) -> dict:
     """
-
-    def __init__(self, *,
-                 message: Optional[str] = None,
-                 error: Optional[str] = None,
-                 context: Optional[Context] = None,
-                 progress: Optional[Progress] = None):
-        self.message = message
-        self.error = error
-        self.context = context
-        self.progress = progress
-
-    def as_dict(self):
-        return omitempty({
-            "message": self.message,
-            "error": self.error,
-            "context": self.context.as_dict(),
-            "progress": self.progress.as_dict(),
-            "timestamp": time.time(),
-        })
+    Create a single log entry dict with a given message, context, and progress objects.
+    All arguments are optional. A timestamp is added to the message.
+    """
+    # we probably want to add an (optional) error message here too once the
+    # monitors support that
+    return omitempty({
+        "message": message,
+        "context": context.as_dict() if context else None,
+        "progress": progress.as_dict() if progress else None,
+        "timestamp": time.time(),
+    })
 
 
 class TextWriter:
@@ -331,16 +321,15 @@ class JSONSeqMonitor(BaseMonitor):
         oo = self._context.origin
         if origin is not None:
             self._context.origin = origin
-        line = LogLine(message=message, context=self._context, progress=self._progress)
-        self._jsonseq(line.as_dict())
-        # needs to be here as LogLine has a ref to self._context so updates
-        # before line.as_dict() will be have a different context
+        entry = log_entry(message=message, context=self._context, progress=self._progress)
+        self._jsonseq(entry)
+        # restore old origin
         self._context.origin = oo
 
-    def _jsonseq(self, data):
+    def _jsonseq(self, entry):
         # follow rfc7464 (application/json-seq)
         self.out.write("\x1e")
-        json.dump(data, self.out)
+        json.dump(entry, self.out)
         self.out.write("\n")
 
 

test/mod/test_monitor.py

@@ -7,13 +7,14 @@ import json
 import os
 import sys
 import tempfile
+import time
 import unittest
 from collections import defaultdict
 
 import osbuild
 import osbuild.meta
 from osbuild.monitor import LogMonitor
-from osbuild.monitor import JSONSeqMonitor, Context, Progress, LogLine
+from osbuild.monitor import JSONSeqMonitor, Context, Progress, log_entry
 from osbuild.objectstore import ObjectStore
 from osbuild.pipeline import Runner
 
@@ -241,3 +242,21 @@ def test_json_progress_monitor():
         assert logitem["message"] == "pipeline 2 starting"
         assert logitem["context"]["origin"] == "org.osbuild"
         assert logitem["context"]["pipeline"]["name"] == "test-pipeline-second"
+
+
+def test_log_line_empty_is_fine():
+    empty = log_entry()
+    assert len(empty) == 1
+    assert empty["timestamp"] > time.time()-60
+    assert empty["timestamp"] < time.time()+60
+
+
+def test_log_line_with_entries():
+    ctx = Context("some-origin")
+    progress = Progress(name="foo", total=2)
+    entry = log_entry("some-msg", ctx, progress)
+    assert len(entry) == 4
+    assert entry["message"] == "some-msg"
+    assert isinstance(entry["context"], dict)
+    assert isinstance(entry["progress"], dict)
+    assert entry["timestamp"] > 0