Control stack trace verbosity

When working with Julia, you may come across situations where you need to control the verbosity of the control stack trace. The control stack trace provides information about the sequence of function calls that led to an error or exception. By default, Julia displays a full stack trace, which can be overwhelming and difficult to interpret in some cases. In this article, we will explore three different ways to control the stack trace verbosity in Julia.

Option 1: Using the `–verbosity` flag

One way to control the stack trace verbosity is by using the `–verbosity` flag when running your Julia code from the command line. This flag allows you to specify the level of verbosity you want to see in the stack trace. The available options are:

• `–verbosity=0`: Only display the error message without any stack trace.
• `–verbosity=1`: Display a concise stack trace with function names and line numbers.
• `–verbosity=2`: Display a full stack trace with function names, line numbers, and source code snippets.

To use this option, you can simply add the `–verbosity` flag followed by the desired level of verbosity when running your Julia code. For example:

julia --verbosity=1 my_script.jl

Option 2: Setting the `JULIA_DEBUG` environment variable

Another way to control the stack trace verbosity is by setting the `JULIA_DEBUG` environment variable before running your Julia code. This variable allows you to specify the level of verbosity you want to see in the stack trace. The available options are the same as in Option 1.

To set the `JULIA_DEBUG` environment variable, you can use the following command:

export JULIA_DEBUG=1

After setting the environment variable, you can run your Julia code as usual, and the stack trace will be displayed according to the specified verbosity level.

Option 3: Using the `Base.StackTraces.setverbosity!` function

The third option to control the stack trace verbosity is by using the `Base.StackTraces.setverbosity!` function in your Julia code. This function allows you to dynamically change the verbosity level during runtime.

To use this function, you can add the following code snippet at the beginning of your Julia script:

Base.StackTraces.setverbosity!(1)

This code sets the verbosity level to 1, which will display a concise stack trace. If you want to change the verbosity level to a different value, you can simply modify the argument passed to the `setverbosity!` function.

After setting the verbosity level, you can run your Julia code, and the stack trace will be displayed according to the specified verbosity level.

Out of the three options discussed above, the best option depends on your specific requirements and preferences. If you want to control the stack trace verbosity globally for all Julia code executions, Option 2 (setting the `JULIA_DEBUG` environment variable) might be the most convenient. On the other hand, if you need to control the verbosity level dynamically during runtime, Option 3 (using the `Base.StackTraces.setverbosity!` function) would be the most suitable. Option 1 (using the `–verbosity` flag) is useful when you want to control the verbosity level on a per-execution basis from the command line.