[core] log dedup should not dedup number only lines (ray-project#45485)

Signed-off-by: hongchaodeng <hongchaodeng1@gmail.com>

python/ray/_private/ray_logging.py

@@ -284,11 +284,16 @@ def deduplicate(self, batch: LogBatch) -> List[LogBatch]:
                 continue
             dedup_key = _canonicalise_log_line(line)
 
+            if dedup_key == "":
+                # Don't dedup messages that are empty after canonicalization.
+                # Because that's all the information users want to see.
+                output[0]["lines"].append(line)
+                continue
+
             if dedup_key in self.recent:
                 sources = self.recent[dedup_key].sources
                 sources.add(source)
-                # We deduplicate the warnings/errorm essages from
-                # raylet by default.
+                # We deduplicate the warnings/error messages from raylet by default.
                 if len(sources) > 1 or batch["pid"] == "raylet":
                     state = self.recent[dedup_key]
                     self.recent[dedup_key] = DedupState(

python/ray/tests/test_log_dedup.py

@@ -19,6 +19,60 @@ def test_nodedup_logs_single_process():
     assert out1 == [batch1]
 
 
+def test_nodedup_logs_buffer_only_lines():
+    now = 142300000.0
+
+    def gettime():
+        return now
+
+    dedup = LogDeduplicator(5, None, None, _timesource=gettime)
+    batch1 = {
+        "ip": "node1",
+        "pid": 100,
+        # numbers are canonicalised, so this would lead to empty dedup_key
+        "lines": ["1"],
+    }
+
+    # Immediately prints always.
+    out1 = dedup.deduplicate(batch1)
+    assert out1 == [batch1]
+
+    now += 1.0
+
+    # Should print new lines even if it is number only again
+    batch2 = {
+        "ip": "node2",
+        "pid": 200,
+        "lines": ["2"],
+    }
+    out2 = dedup.deduplicate(batch2)
+    assert out2 == [
+        {
+            "ip": "node2",
+            "pid": 200,
+            "lines": ["2"],
+        }
+    ]
+
+    now += 3.0
+
+    # Should print new lines even if it is same number
+    batch3 = {
+        "ip": "node3",
+        "pid": 300,
+        "lines": ["2"],
+    }
+    # Should buffer duplicates.
+    out3 = dedup.deduplicate(batch3)
+    assert out3 == [
+        {
+            "ip": "node3",
+            "pid": 300,
+            "lines": ["2"],
+        }
+    ]
+
+
 def test_dedup_logs_multiple_processes():
     now = 142300000.0