Logging for later analysis

General Usage
1

Hi,

Inside Logging documentation, it says “the logging tools allow you to attach arbitrary data to each event as a set of key–value pairs. This allows you to capture local variables and other program state for later analysis”.

Well, I want to do that:

using Logging

times7 = Dict{Int, Int}()

function logtest(n::Int)
  for i in 1:n
    if i % 7 == 0
      @info "divisible by 7" times7[i] = (i / 7)^2
    end  
  end
end

logger = SimpleLogger()

with_logger(logger) do 
  logtest(100)
end

So, I want to view the logged records later on (records inside logger). Maybe to compute some statistics or plotting the algorithm history, etc. Is this possible?

Thanks!

2

SimpleLogger takes an argument of type IO.

julia> using Logging

julia> iobuf = IOBuffer()
IOBuffer(data=UInt8[...], readable=true, writable=true, seekable=true, append=false, size=0, maxsize=Inf, ptr=1, mark=-1)

julia> logger = SimpleLogger(iobuf)
Base.CoreLogging.SimpleLogger(IOBuffer(data=UInt8[...], readable=true, writable=true, seekable=true, append=false, size=0, maxsize=Inf, ptr=1, mark=-1), Info, Dict{Any, Int64}())

julia> with_logger(logger) do
           logtest(100)
       end

julia> println(String(take!(iobuf)))
┌ Info: divisible by 7
│   times7[i] = 1.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 4.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 9.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 16.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 25.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 36.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 49.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 64.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 81.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 100.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 121.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 144.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 169.0
└ @ Main REPL[44]:4
┌ Info: divisible by 7
│   times7[i] = 196.0
└ @ Main REPL[44]:4

You could also just make a custom logger:
https://docs.julialang.org/en/v1/stdlib/Logging/#AbstractLogger-interface

1 Like
3

No really what I meant but custom logger it is then. Thanks!