Include test for local logger instances in mbreceiver (#47257)

Author: khushijain21

x-pack/metricbeat/mbreceiver/receiver_test.go

@@ -207,6 +207,16 @@ func TestMultipleReceivers(t *testing.T) {
 			assert.Equal(c, "receiver", logs["r1"][0].Flatten()["agent.otelcol.component.kind"], "expected agent.otelcol.component.kind field in r1 log record")
 			assert.Equal(c, "metricbeatreceiver/r2", logs["r2"][0].Flatten()["agent.otelcol.component.id"], "expected agent.otelcol.component.id field in r2 log record")
 			assert.Equal(c, "receiver", logs["r2"][0].Flatten()["agent.otelcol.component.kind"], "expected otelcol.component.kind field in r2 log record")
+
+			// Make sure that each receiver has a separate logger
+			// instance and does not interfere with others. Previously, the
+			// logger in Beats was global, causing logger fields to be
+			// overwritten when multiple receivers started in the same process.
+			r1StartLogs := zapLogs.FilterMessageSnippet("Beat ID").FilterField(zap.String("otelcol.component.id", "metricbeatreceiver/r1"))
+			assert.Equal(c, 1, r1StartLogs.Len(), "r1 should have a single start log")
+			r2StartLogs := zapLogs.FilterMessageSnippet("Beat ID").FilterField(zap.String("otelcol.component.id", "metricbeatreceiver/r2"))
+			assert.Equal(c, 1, r2StartLogs.Len(), "r2 should have a single start log")
+
 			var lastError strings.Builder
 			assert.Conditionf(c, func() bool {
 				tests := []string{monitorSocket1, monitorSocket2}