etcdserver: add TestErrorLogs test to check for error logs

Signed-off-by: NitishKumar06 <justnitish06@gmail.com>

fix static analysis check

Signed-off-by: NitishKumar06 <justnitish06@gmail.com>

minor fixes

Signed-off-by: NitishKumar06 <justnitish06@gmail.com>

tests/e2e/logging_test.go

@@ -0,0 +1,64 @@
+// Copyright 2024 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package e2e
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"go.etcd.io/etcd/tests/v3/framework/e2e"
+)
+
+func TestNoErrorLogsDuringNormalOperations(t *testing.T) {
+	e2e.BeforeTest(t)
+	ctx := context.TODO()
+
+	epc, err := e2e.NewEtcdProcessCluster(ctx, t,
+		e2e.WithClusterSize(1),
+		e2e.WithLogLevel("debug"),
+	)
+	require.NoError(t, err)
+	defer epc.Close()
+
+	logs := epc.Procs[0].Logs()
+	time.Sleep(time.Second)
+	if err = epc.Close(); err != nil {
+		t.Fatalf("error closing etcd processes (%v)", err)
+	}
+	var entry logEntry
+	lines := logs.Lines()
+	if len(lines) == 0 {
+		t.Errorf("Expected at least one log line")
+	}
+
+	allowedErrors := map[string]bool{"setting up serving from embedded etcd failed.": true}
+
+	for _, line := range lines {
+		err := json.Unmarshal([]byte(line), &entry)
+		if err != nil {
+			t.Errorf("Failed to parse log line as json, err: %q, line: %s", err, line)
+			continue
+		}
+		if allowedErrors[entry.Message] {
+			continue
+		}
+
+		require.NotEqual(t, "error", entry.Level)
+	}
+}