private bool IsExpiredGlobalTx(QueryGlobalTransactionDetailReply globalTx)
{
var delta = DateTime.UtcNow - DateTimeOffset.FromUnixTimeSeconds(globalTx.CreatedAt).UtcDateTime;
var expireTimeSpan = TimeSpan.FromSeconds(globalTx.ExpireSeconds); // saga事务超时时间
return(delta > expireTimeSpan);
}
private async Task ProcessUnfinishedSagaAsync(QueryGlobalTransactionDetailReply globalTx)
{
// 对补偿中或者补偿过程中有失败的全局事务的分支事务找到关注的分支事务（根据branchTx.serviceKey)
// 执行各自的补偿方法，并修改分支状态
// 如果某个分支的补偿key为空，则直接修改分支状态
var xid = globalTx.Xid;
var branches = globalTx.Branches;
var watchedBranches = new List <TransactionBranchDetail>();
Dictionary <string, Func <object, Task> > serviceMethods = new Dictionary <string, Func <object, Task> >();
foreach (var branch in branches)
{
var branchServiceKey = branch.BranchServiceKey;
// 根据branchServiceResolver 找出关注的branches. 暂时关注所有branch
var branchService = _branchServiceResolver.ResolveBranch(branchServiceKey);
if (branchService == null)
{
continue;
}
watchedBranches.Add(branch);
serviceMethods[branchServiceKey] = branchService;
}
// 如果没有关注的branches，返回
if (watchedBranches.Count < 1)
{
return;
}
watchedBranches.Reverse(); // watchedBranches改成倒叙，这是为了优先执行补偿后到的分支
// 执行回滚，以及修改分支状态
foreach (var branch in watchedBranches)
{
var branchId = branch.BranchId;
var branchCompensationServiceKey = branch.BranchCompensationServiceKey;
var oldBranchState = branch.State;
var oldBranchVersion = branch.Version;
var jobId = Guid.NewGuid().ToString();
if (branchCompensationServiceKey == null || branchCompensationServiceKey.Length < 1)
{
// 补偿方法为空，直接标记为已经补偿
await _sagaCollaborator.SubmitBranchTxStateAsync(xid, branchId,
oldBranchState, TxState.CompensationDone, oldBranchVersion, jobId, "", null);
continue;
}
// 调用 branchServiceResolver 去执行补偿方法
var branchCompensationService = _branchServiceResolver.ResolveBranch(branchCompensationServiceKey);
// 调用成功后标记为已经补偿，如果调用失败或者没有找到补偿方法，上报补偿失败
var compensationSuccess = false;
var errorReason = "";
if (branchCompensationService != null)
{
try
{
// 从saga server取到saga data
var sagaDataReply = await _sagaCollaborator.GetSagaDataAsync(xid);
byte[] sagaDataBytes = sagaDataReply.Data.ToByteArray();
var sagaData = _sagaDataConverter.Deserialize <SagaData>(sagaDataTypeResolver, sagaDataBytes);
await branchCompensationService(sagaData);
var changedSagaDataBytes = _sagaDataConverter.Serialize(typeof(SagaData), sagaData);
await _sagaCollaborator.SubmitBranchTxStateAsync(xid, branchId, branch.State,
TxState.CompensationDone, branch.Version, jobId, "", changedSagaDataBytes);
compensationSuccess = true;
} catch (Exception e)
{
compensationSuccess = false;
errorReason = e.Message;
_logger.LogError($"branch {branchId} compensation error", e);
}
}
if (!compensationSuccess)
{
_logger.LogError($"branch compensation {branchCompensationServiceKey} fail");
try
{
var latestBranch = await _sagaCollaborator.QueryBranchTxAsync(branchId);
await _sagaCollaborator.SubmitBranchTxStateAsync(xid,
branchId, latestBranch.Detail.State, TxState.CompensationError,
latestBranch.Detail.Version, jobId, errorReason, null);
}
catch (Exception e2)
{
_logger.LogError($"SubmitBranchTxStateAsync o branch {branchId} error", e2);
}
}
}
}
