LogReceiver is a JMS message producer that listens on a log file and picks up new log entries. The log entries will be converted into JMS messages. Then they will be put into the atached XQueue as the output. LogReceiver requires the log file having a decent timestamp on each entry. Only one operation, fetch, is supported. LogReceiver also supports flow control and XA. Fault tolerance with auto reconnections is built in.

LogReceiver supports 4 different transcation mode determined by XAMode. For XAMode = 1 or 3, the client based transcation is enabled so that the commit is done by the persister when it completes to persist the message. If XAMode = 2, the session commit is enabled so that the commit will be done when the read operation finishes and the log file is closed. The session can be forced to termination if MaxNumberMessage is larger than 0 and the total number of processed logs and dropped logs exceeds it. For XAMode = 0, the auto commit is enabled. In this case, the persistence of the state info is determined by SaveReference. By default, SaveReference is set to be true. It means the state info will be flushed to the disk on every processed log entry. If SaveReference is set to false, otherwise, the state info will not saved to the reference file.

LogReceiver is reliable and super fast. For a typical Apache log, it can easily pick up more than 10,000 logs per second. When the log volume is high, LogReceiver may consume high CPU to catch up the log feeds. To reduce the CPU usage, the session commit with a reasonable MaxNumberMessage should be considered.

Apart from the common properties, there are many implementation specific properties for LogReceiver.

Property Name	Data Type	Requirement	Description	Examples
TimePattern	string	mandatory	Simple Time Pattern to parse the timestamp	yyyy-MM-dd HH:mm:ss,SSS
LogSize	integer	optional	max number of lines of a log entry	1 (default: 50)
OldLogfile	string	optional	filename of rotated logfile after the rotation	/var/log/qbroker/my.log.1
ReferenceFile	string	mandatory	filename to store the state info	/var/log/qbroker/.status/event.log
SaveReference	string of true or false	optional	flag to save the state info to disk	true (default: true)
MaxNumberMessage	integer	optional	max number of logs to pick up within a session	1024 (default: 0 for no limit)
PatternGroup	list	optional	list of PatternGroups to select certain logs	see example
XPatternGroup	list	optional	list of PatternGroups to exclude certain logs	see example

where ResultType specifies what data type is used for the query result.

Here is an example of LogReceiver:

{
  "Name": "rcvr_msf_q",
  "ClassName": "org.qbroker.receiver.LogReceiver",
  "URI": "log:///var/log/qbroker/incoming/msf_q",
  "LinkName": "root",
  "OldLogfile": "/var/log/qbroker/incoming/msf_q.1",
  "Operation": "fetch",
  "TimePattern": "yyyy-MM-dd HH:mm:ss,SSS zz",
  "LogSize": "1",
  "ReferenceFile": "/var/log/qbroker/.status/msf_q",
  "Capacity": "1024",
  "Partition": "0,0",
  "PatternGroup": [{
    "Pattern": ["."]
  }],
  "Mode": "daemon",
  "XAMode": "1",
  "TextMode": "1",
  "ReceiveTime": "1000",
  "MaxNumberMessage": "0",
  "Tolerance": "0",
  "MaxRetry": "2",
  "DisplayMask": "0",
  "DependencyGroup": [{
    "Dependency": [{
      "Name": "file_q",
      "URI": "file:///var/log/qbroker/incoming/msf_q",
      "Type": "FileTester"
    }]
  }]
}