[RATIS-552] Instrument LogService with metrics framework

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.3.0
• Assignee: Ankit Singhal
• Reporter: Ankit Singhal
• Created: 14/May/19 00:29
• Updated: 29/May/19 16:03
• Resolved: 29/May/19 16:03

Description

Basic metric implemented through timer to get :-

• No. of requests
• Histogram for the time taken by the request
• Request rate etc

Metrics collected at server for LogStream

MetricName	Metric description
readNextQueryTime	Read request from reader on next() call
startIndexTime	Request to get start index of the log
sizeRequestTime	request to get size of the log
getStateTime	request to get state of log(currently managed at client so may be 0 all the time)
lastIndexQueryTime	request to get last index of the log
lengthQuery	request to get length of the log

Metric collected at Metadata service

MetricName	Metric description
CREATELOG	request to create log
DELETELOG	request to delete log
LISTLOG	request to list log
GETLOG	request to get log
ARCHIVELOG	request to archive log