fix(logs): correct metricIncomingLogEvents metric name from IncomingLogs to IncomingLogEvents

The metricIncomingLogEvents() method was using 'IncomingLogs' as the
metric name, but the correct CloudWatch metric name per AWS documentation
is 'IncomingLogEvents'. This caused alarms created with this method to
have no datapoints.

Closes #36815

Author: syukawa-dev

packages/aws-cdk-lib/aws-logs/lib/log-group.ts

@@ -343,7 +343,7 @@ abstract class LogGroupBase extends Resource implements ILogGroup {
    * ```
    */
   public metricIncomingLogEvents(props?: cloudwatch.MetricOptions): cloudwatch.Metric {
-    return this.metric('IncomingLogs', props);
+    return this.metric('IncomingLogEvents', props);
   }
 
   /**

packages/aws-cdk-lib/aws-logs/test/loggroup.test.ts

@@ -339,6 +339,26 @@ describe('log group', () => {
     expect(metric.metricName).toEqual('Field');
   });
 
+  test('metricIncomingLogEvents uses correct metric name', () => {
+    const stack = new Stack();
+    const lg = new LogGroup(stack, 'LogGroup');
+
+    const metric = lg.metricIncomingLogEvents();
+
+    expect(metric.metricName).toEqual('IncomingLogEvents');
+    expect(metric.namespace).toEqual('AWS/Logs');
+  });
+
+  test('metricIncomingBytes uses correct metric name', () => {
+    const stack = new Stack();
+    const lg = new LogGroup(stack, 'LogGroup');
+
+    const metric = lg.metricIncomingBytes();
+
+    expect(metric.metricName).toEqual('IncomingBytes');
+    expect(metric.namespace).toEqual('AWS/Logs');
+  });
+
   test('extractMetric allows passing in namespaces with "/"', () => {
     // GIVEN
     const stack = new Stack();