serves logs and prometheus metrics to help trace a function execution at runtime.

fabric-flogging is cloned from flogging of Hyperledger Fabric at https://github.com/hyperledger/fabric/tree/master/common/flogging

1. Define tracing

var myTracer  = tracing.MustGetTracer("example_file")

2. Count on function call

call StartFunction() at the beginning of the function call. For example

func myfunction(){
    myTracer.StartFunction("my_trace_number")
    // function logic
}

2022-12-22 13:43:09.339 +07 [example_file] myfunction -> INFO 026 [my_trace_number] StartFunction at 1671691389339

3. Count on function end

call EndFunction() at the end of the function call. For example

func myfunction(){

    // function logic
    myTracer.EndFunction("my_trace_number")
}

2022-12-22 13:43:09.339 +07 [example_file] myfunction -> INFO 026 [my_trace_number] EndFunction at 1671691389339

4. Trace function duration

• option 1: call EndFunctionWithDurationSince() at the end of the function call. For example

func myfunction(){
    startTime := myTracer.StartFunction("my_trace_number")
    // function logic
    myTracer.EndFunctionWithDurationSince("my_trace_number", startTime)
}

• option 2: call EndFunctionWithDurationSince() with defer at the beginning of function call. For example

func myfunction(){
    defer myTracer.EndFunctionWithDurationSince("my_trace_number", time.Now())
    // function logic
}

both options will have the same logging like this

2022-12-22 13:43:09.891 +07 [example_file] myfunction -> INFO 02f [my_trace_number] EndFunction at 1671691389891, duration=551ms

check URL:PORT/metrics to find prometheus metrics