log4rs | A highly configurable logging framework for Rust

You can only call init_config once. However, it returns a handle with a set_config method, which you can call to change the configuration afterwards:

You can implement it via using RollingFileAppender CompoundPolicy , FixedWindowRoller and SizeTrigger from log4rs crate.

You need to implement the followings in order to create your rolling file logic:

1. FixedWindowRoller

Specify FixedWindowRoller to roll your log file in a fixed window_size like following:

When you type cargo run, your working directory is the current directory. This means that all your relative paths will depend on this working directory.

For example, if you are in your home directory (~) and you have your project folder named foo. When you go in it, that gives you ~/foo. If you now type cargo run, that means that when log4rs tries to open your file it will try to open the file ~/foo/log4rs.yml. The file is not here but in ~/foo/src/log4rs.yml

You have many solutions:

• log4rs::init_file("src/log4rs.yml", Default::default()).unwrap();
• move log4rs.yml to foo
• use an absolute path (not a good solution for your current case)

Inspecting the build.rs file supplied with openssl-sys, I noticed two things.

1. If you do not set both OPENSSL_LIB_DIR and OPENSSL_INCLUDE_DIR, then it will try to detect the OpenSSL directories by calling pkg-config. If that succeeds (and it does in my system) then it will exit early, and never even considers the value of OPENSSL_STATIC.

   Arguably that's a bug, but I found that if I used this command line:

Is this the only way to do it?

Semantically it is the critical way, though there are other ways to write it. The appender function takes mut self so it will take ownership of the cb variable's value and make the variable unusable after that point. It could have been designed to borrow a reference, but chaining is nice. Since you're in a loop, the builder needs to be available on the next iteration, so you need to assign the value to something new. This means that