Types of Metrics
- Counter:
- These are type of metrics which will use track either the number or size of the events
- Examples
- Request Count
- Exception Count
- Size of records processed
- Gauge:
- These are snapshot of some current state
- While for counters how fast it is increase is what we care about, for gauge it is actual value of gauge
- Examples
- number of items in queue
- memory usage of a cache
- number of active threads
- Histogram:
- A summary while provide the average latency, but waht if you want quanitile?
- Quantile tells you that a certain proportion of events had a size belo a give value.
- For example: 0.95 quantile being 300 ms meants that 95% of requests took less than 300 ms
Instrumentation
- The largest payoffs you will get from prometheus are through instrumenting your own applications using direct instrumentation and client library
- Refer Here for the sample instrumentation code
