RedisとVB.NETを使ってリアルタイムログ収集機能を実装する方法

Imports StackExchange.Redis

Public Class RedisHelper
    Private Shared redis As ConnectionMultiplexer

    Public Shared Function GetConnection() As IDatabase
        If redis Is Nothing Then
            redis = ConnectionMultiplexer.Connect("localhost")
        End If
        Return redis.GetDatabase()
    End Function
End Class

Public Class Program
    Public Shared Sub Main(args As String())
        Dim db As IDatabase = RedisHelper.GetConnection()

        ' 在Redis中写入日志
        db.StringSet("log:1", "2022-01-01 00:00:00 - User 1 logged in")

        ' 从Redis中读取日志
        Dim log As String = db.StringGet("log:1")
        Console.WriteLine(log)
    End Sub
End Class

Imports StackExchange.Redis
Imports System.Threading

Public Class RedisHelper
    ' 省略前面的代码

    Public Shared Sub WriteLog(log As String)
        Dim db As IDatabase = GetConnection()

        ' 生成唯一的时间戳作为日志的键
        Dim timestamp As String = DateTime.Now.ToString("yyyyMMddHHmmssfff")
  
        ' 将日志写入Redis
        db.StringSet("log:" + timestamp, log)
    End Sub
End Class

Public Class Program
    Public Shared Sub Main(args As String())
        Dim timer As New Timer(AddressOf WriteLogCallback, Nothing, TimeSpan.Zero, TimeSpan.FromSeconds(1))

        Console.WriteLine("Press any key to exit...")
        Console.ReadKey()

        timer.Dispose()
    End Sub

    Public Shared Sub WriteLogCallback(state As Object)
        RedisHelper.WriteLog(DateTime.Now.ToString() + " - User 1 logged in")
    End Sub
End Class

Imports StackExchange.Redis

Public Class RedisHelper
    ' 省略前面的代码

    Public Shared Function ReadLogs() As IEnumerable(Of String)
        Dim db As IDatabase = GetConnection()

        ' 获取Redis中所有的日志键
        Dim logKeys As IEnumerable(Of RedisKey) = db.KeyScan()

        ' 根据时间戳降序排序日志键
        Dim sortedLogKeys As List(Of RedisKey) = logKeys.OrderByDescending(Function(key) key).ToList()

        ' 获取最新的10条日志
        Dim logs As List(Of String) = New List(Of String)()

        For Each logKey In sortedLogKeys.Take(10)
            Dim log As String = db.StringGet(logKey)
            logs.Add(log)
        Next

        Return logs
    End Function
End Class

Public Class Program
    Public Shared Sub Main(args As String())
        While True
            Dim logs As IEnumerable(Of String) = RedisHelper.ReadLogs()

            Console.WriteLine("Latest 10 logs:")
            For Each log In logs
                Console.WriteLine(log)
            Next

            Thread.Sleep(1000)
        End While
    End Sub
End Class