[ray][metrics] Replace ':' with '_' for OpenTelemetry compatibility in Ray (#25439)

Signed-off-by: Seiji Eicher <seiji@anyscale.com>
Signed-off-by: Seiji Eicher <58963096+eicherseiji@users.noreply.github.com>
Co-authored-by: Rui Qiao <161574667+ruisearch42@users.noreply.github.com>

tests/v1/metrics/test_ray_metrics.py

@@ -8,7 +8,8 @@ import ray
 from vllm.config import ModelDType
 from vllm.sampling_params import SamplingParams
 from vllm.v1.engine.async_llm import AsyncEngineArgs, AsyncLLM
-from vllm.v1.metrics.ray_wrappers import RayPrometheusStatLogger
+from vllm.v1.metrics.ray_wrappers import (RayPrometheusMetric,
+                                          RayPrometheusStatLogger)
 
 
 @pytest.fixture(scope="function", autouse=True)
@@ -65,3 +66,39 @@ def test_engine_log_metrics_ray(
     # Create the actor and call the async method
     actor = EngineTestActor.remote()  # type: ignore[attr-defined]
     ray.get(actor.run.remote())
+
+
+def test_sanitized_opentelemetry_name():
+    """Test the metric name sanitization logic for Ray."""
+
+    # Only a-z, A-Z, 0-9, _, test valid characters are preserved
+    valid_name = "valid_metric_123_abcDEF"
+    assert RayPrometheusMetric._get_sanitized_opentelemetry_name(
+        valid_name) == valid_name
+
+    # Test dash, dot, are replaced
+    name_with_dash_dot = "metric-name.test"
+    expected = "metric_name_test"
+    assert RayPrometheusMetric._get_sanitized_opentelemetry_name(
+        name_with_dash_dot) == expected
+
+    # Test colon is replaced with underscore
+    name_with_colon = "metric:name"
+    expected = "metric_name"
+    assert RayPrometheusMetric._get_sanitized_opentelemetry_name(
+        name_with_colon) == expected
+
+    # Test multiple invalid characters are replaced
+    name_with_invalid = "metric:name@with#special%chars"
+    expected = "metric_name_with_special_chars"
+    assert RayPrometheusMetric._get_sanitized_opentelemetry_name(
+        name_with_invalid) == expected
+
+    # Test mixed valid and invalid characters
+    complex_name = "vllm:engine_stats/time.latency_ms-99p"
+    expected = "vllm_engine_stats_time_latency_ms_99p"
+    assert RayPrometheusMetric._get_sanitized_opentelemetry_name(
+        complex_name) == expected
+
+    # Test empty string
+    assert RayPrometheusMetric._get_sanitized_opentelemetry_name("") == ""