Implement logging mechanism #4

Open ranocha opened 4 years ago

In GitLab by @sloede on Mar 14, 2020, 12:25

Store all regular output plus additional debug information in a log file such that it can be recovered later, e.g., in out/trixi_YYYMMDDHHmmss.log

The logging mechanism of Julia (https://docs.julialang.org/en/v1/stdlib/Logging/) should be used. The idea is the following (roughly as discussed with Gregor):

All output to console or log files actually goes through logging infrastructure
We use only two standard log levels, i.e., @info and @debug
- @info is the normal runtime output
- @debug is additional output that can help with debugging
By default, @info goes to stdout while @debug is not evaluated at all.
If log=True or log=<filename> is provided to run(), all @info messages go additionally to out/trixi.log or out/<filename>.log
If debug=True is provided to run() (or ENV["JULIA_DEBUG"] is set appropriately), all @debug messages are shown at stdout as well. In combination with log=True/<filename>, however, debug messages will only be shown in the log file.

It might be interesting to enable other default output if logging-to-file is enabled, e.g., to copy the parameters file used to the beginning of the log file, or some information on when and where and with which command line arguments trixi was started.

Potential use cases where it might be interesting to have a permanent log:

AMR: current number of elements; elements added/removed; number of elements at each level
shock capturing: information about minimum/maximum alpha values; number of pure DG/blended DG-FV elements

In GitLab by @sloede on Mar 18, 2020, 12:56

changed the description

In GitLab by @sloede on Mar 24, 2020, 09:10

changed the description

In GitLab by @sloede on May 13, 2020, 09:30

changed the description

I am not sure what the proper way to implement logging in Trixi is. Obviously every println(...) will need to be replaced by an @info or @debug. But how should we control the logging level?

Should we explicitly provide a logger using

with_logger(logger) do
    [...]
end

somewhere in Trixi.run? Or should we rather use the default (global) logger and control logging levels with the environment variable?

It would be nice to get this to be able to use https://github.com/JuliaLogging/LoggingExtras.jl

A tee-like option may be Base.BufferStream, see https://discourse.julialang.org/t/write-to-file-and-stdout/35042/13

Out of curiosity, what would this enable?

On Thu, May 23, 2024 at 12:36 PM Hendrik Ranocha @.***> wrote:

A tee-like option may be Base.BufferStream, see https://discourse.julialang.org/t/write-to-file-and-stdout/35042/13

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Printing the output to a file and the screen - something several people have asked on Slack

trixi-framework / Trixi.jl

Implement logging mechanism #4