public static void Log(Command c, string columnName, int partition)
{
var colId = String.Format("{0,15}", $"[{columnName}|{partition}]");
var summary = c switch
{
Command_Change cmd => $"{colId} CHANGE {cmd.ColumnValue} | {cmd.ChangeType}",
Command_Enter cmd => $"{colId} ENTER {cmd.ColumnValue}",
Command_Verify cmd => $"{colId} VERIFY {cmd.SourceColumnName} | {cmd.SourceColumnValue}",
Command_Exit cmd => $"{colId} EXIT {cmd.ColumnValue}",
Command_Ack cmd => $"{colId} ACK {cmd.SourceColumnName} | {cmd.SourceColumnValue}",
_ => $"unknown command"
};
var logLine = String.Format("{0,-60} .." + c.Correlation.Substring(c.Correlation.Length - 8), summary);
Console.WriteLine(logLine);
}
private void HandleVerify(Command_Verify cmd, Offset offset)
{
if (!inProgressState_Active.ContainsKey(cmd.Correlation))
{
// This could occur in the case of duplicate writes and can be safely ignored.
Logger.Log("VERIFY", $"Received verify command with no corresponding waitingVerify entry, ignoring [{cmd.Correlation}]");
return;
}
// all verify results must be true for command to succeed.
if (!cmd.Verified)
{
inProgressState_Active[cmd.Correlation].VerifyFailed.Add(new NameAndValue {
Name = cmd.SourceColumnName, Value = cmd.SourceColumnValue
});
}
// remove the received column from list we're waiting on.
inProgressState_Active[cmd.Correlation].WaitingVerify = inProgressState_Active[cmd.Correlation]
.WaitingVerify.Where(a => !(a.Name == cmd.SourceColumnName && a.Value == cmd.SourceColumnValue))
.ToList();
// if we're waiting on more, then there's nothing left to do here.
if (inProgressState_Active[cmd.Correlation].WaitingVerify.Count > 0)
{
return;
}
// --- verification result has been received for all columns.
// Logger.Log("VERIFY", $"All verify commands received for: [{cmd.Correlation}]");
var inProgress = inProgressState_Active[cmd.Correlation];
var aborting = inProgress.VerifyFailed.Count > 0;
// send exit_commands for columns that are to be set (or abort).
// note: does not include the current "this" column - that is handled as a special case.
foreach (var col in inProgress.ToSet)
{
Dictionary <string, string> dataToSet = null;
if (!aborting)
{
dataToSet = new Dictionary <string, string>(inProgress.Data);
dataToSet.Add(this.columnName, inProgress.ColumnValue);
dataToSet.Remove(col.Key);
}
var exitCommand = new Command_Exit
{
Correlation = cmd.Correlation,
ColumnValue = inProgress.Data[col.Key],
Action = aborting ? ActionType.Abort : ActionType.Set,
Data = dataToSet,
SourceColumnName = this.columnName,
SourceColumnValue = inProgress.ColumnValue
};
var tp = new TopicPartition(
tableSpecification.CommandTopicName(col.Key),
Table.Partitioner(exitCommand.ColumnValue, this.numPartitions));
cmdProducer.ProduceAsync(tp, new Message <Null, string> {
Value = JsonConvert.SerializeObject(exitCommand, Formatting.Indented, jsonSettings)
})
.FailIfFaulted("VERIFY", "produce fail");
}
// send exit_commands for column values that are to be deleted (or abort).
foreach (var col in inProgress.ToDelete)
{
var exitCommand = new Command_Exit
{
Correlation = cmd.Correlation,
ColumnValue = col.Value,
Action = aborting ? ActionType.Abort : ActionType.Delete,
Data = null,
SourceColumnName = this.columnName,
SourceColumnValue = inProgress.ColumnValue
};
var tp = new TopicPartition(
tableSpecification.CommandTopicName(col.Key),
Table.Partitioner(exitCommand.ColumnValue, this.numPartitions));
cmdProducer.ProduceAsync(tp, new Message <Null, string> {
Value = JsonConvert.SerializeObject(exitCommand, Formatting.Indented, jsonSettings)
})
.FailIfFaulted("VERIFY", "produce fail");
}
// if aborting, clean up everything now - there will be no acks.
if (aborting)
{
locked.Remove(inProgress.ColumnValue);
blockedForCommit.Remove(inProgress.ChangeCommandOffset);
inProgressState_Active.Remove(cmd.Correlation);
CompleteChangeRequest(cmd.Correlation, new Exception("columns verify failed"));
return;
}
}
private void HandleEnter(Command_Enter cmd, Offset offset)
{
bool canChange = true;
// deal with case where value is locked already.
if (locked.ContainsKey(cmd.ColumnValue))
{
if (locked[cmd.ColumnValue] != cmd.Correlation) // dedupe.
{
Logger.Log("ENTER", $"Duplicate lock command received, ignoring [{cmd.Correlation}]");
return;
}
else
{
Logger.Log("ENTER", $"Attempting to lock key that is already locked: blocking the change operation [{cmd.Correlation}]");
canChange = false;
}
}
// deal with case where value is already materialized.
if (materialized.ContainsKey(cmd.ColumnValue))
{
if (cmd.IsAddCommand)
{
Logger.Log("ENTER", $"Attempting to add a new row with unique column '{this.columnName}' value '{cmd.ColumnValue}' that already exists. [{cmd.Correlation}]");
canChange = false;
}
if (!cmd.IsAddCommand)
{
// in the case of an update, it is fine for the key to exist, if the row corresponds to the one being updated.
if (materialized[cmd.ColumnValue][cmd.SourceColumnName] != cmd.SourceColumnValue)
{
Logger.Log("ENTER", $"Attempting to update a row with unique column '{this.columnName}' value '{cmd.ColumnValue}' that already exists for some other row. [{cmd.Correlation}]");
canChange = false;
}
}
}
var verifyCommand = new Command_Verify
{
Correlation = cmd.Correlation,
Verified = canChange,
SourceColumnName = this.columnName,
SourceColumnValue = cmd.ColumnValue
};
var tp = new TopicPartition(
tableSpecification.CommandTopicName(cmd.SourceColumnName),
Table.Partitioner(cmd.SourceColumnValue, numPartitions));
cmdProducer.ProduceAsync(tp, new Message <Null, string> {
Value = JsonConvert.SerializeObject(verifyCommand, Formatting.Indented, jsonSettings)
})
.FailIfFaulted("ENTER", $"A fatal problem occured writing a verify command.");
// locking is only required if the value may possibly be changing.
if (canChange)
{
// lock the value until the command is complete [this may not be necessary].
locked.Add(cmd.ColumnValue, cmd.Correlation);
// don't allow commit until corresponding exit command
blockedForCommit.Add(offset, cmd.Correlation);
// remember the offset, to remove from blockedForCommit on exit.
inProgressState_Secondary.Add(cmd.Correlation, new InProgressState_Secondary {
EnterCommandOffset = offset
});
}
}
