/// <summary>申请任务分片</summary>
/// <param name="topic">主题</param>
/// <param name="server">申请任务的服务端</param>
/// <param name="ip">申请任务的IP</param>
/// <param name="pid">申请任务的服务端进程ID</param>
/// <param name="count">要申请的任务个数</param>
/// <param name="cache">用于设置全局锁的缓存对象</param>
/// <returns></returns>
public IList <JobTask> AcquireMessage(String topic, String server, String ip, Int32 pid, Int32 count, ICache cache)
{
// 消费消息时，保存主题
if (Topic != topic)
{
Topic = topic;
SaveAsync();
}
var list = new List <JobTask>();
if (!Enable)
{
return(list);
}
// 验证消息数
var now = DateTime.Now;
if (MessageCount == 0 && UpdateTime.AddMinutes(2) > now)
{
return(list);
}
// 全局锁，确保单个作业只有一个线程在分配作业
using var ck = cache.AcquireLock($"Job:{ID}", 5_000);
using var ts = Meta.CreateTrans();
var size = BatchSize;
if (size == 0)
{
size = 1;
}
// 消费消息。请求任务数量=空闲线程*批大小
var msgs = AppMessage.GetTopic(AppID, topic, now, count * size);
if (msgs.Count > 0)
{
for (var i = 0; i < msgs.Count;)
{
var msgList = msgs.Skip(i).Take(size).ToList();
if (msgList.Count == 0)
{
break;
}
i += msgList.Count;
// 创建新的分片
var ti = new JobTask
{
AppID = AppID,
JobID = ID,
Data = msgList.Select(e => e.Data).ToJson(),
MsgCount = msgList.Count,
BatchSize = size,
};
ti.Server = server;
ti.ProcessID = Interlocked.Increment(ref _idxBatch);
ti.Client = $"{ip}@{pid}";
ti.Status = JobStatus.就绪;
ti.CreateTime = DateTime.Now;
ti.UpdateTime = DateTime.Now;
ti.Insert();
list.Add(ti);
}
// 批量删除消息
msgs.Delete();
}
// 更新作业下的消息数
MessageCount = AppMessage.FindCountByAppIDAndTopic(AppID, topic);
UpdateTime = now;
Save();
// 消费完成后，更新应用的消息数
if (MessageCount == 0)
{
var app = App;
if (app != null)
{
app.MessageCount = AppMessage.FindCountByAppID(ID);
app.SaveAsync();
}
}
ts.Commit();
return(list);
}
