add timeunit only for time based meter

Signed-off-by: Ben Efrati <[email protected]>

Author: BenEfrati

implementations/micrometer-registry-otlp/src/main/java/io/micrometer/registry/otlp/OtlpMetricConverter.java

@@ -157,8 +157,9 @@ private static Optional<ExponentialHistogramSnapShot> getExponentialHistogramSna
     }
 
     private void addMaxGaugeForTimer(Meter.Id id, Iterable<KeyValue> tags, double max) {
-        String maxMetricsName = id.getName() + "." + this.baseTimeUnit.toString().toLowerCase() + ".max";
-        Metric.Builder metricBuilder = getOrCreateMetricBuilder(id.withName(maxMetricsName), DataCase.GAUGE);
+        String metricName = id.getName()
+                + (isTimeBasedMeter(id) ? "." + this.baseTimeUnit.toString().toLowerCase() : "") + ".max";
+        Metric.Builder metricBuilder = getOrCreateMetricBuilder(id.withName(metricName), DataCase.GAUGE);
         if (!metricBuilder.hasGauge()) {
             metricBuilder.setGauge(io.opentelemetry.proto.metrics.v1.Gauge.newBuilder());
         }

implementations/micrometer-registry-otlp/src/test/java/io/micrometer/registry/otlp/OTelCollectorIntegrationTest.java

@@ -113,6 +113,7 @@ void collectorShouldExportMetrics() throws Exception {
             containsString("# TYPE test_ds histogram\n"),
             matchesPattern("(?s)^.*test_ds_count\\{.+} 1\\n.*$"),
             matchesPattern("(?s)^.*test_ds_sum\\{.+} 24\\.0\\n.*$"),
+            matchesPattern("(?s)^.*test_ds_max\\{.+} 24\\.0\\n.*$"),
             matchesPattern("(?s)^.*test_ds_bucket\\{.+,le=\"\\+Inf\"} 1\\n.*$")
         );
         // @formatter:on