Crate slog_scope

Logging scopes for slog-rs

Logging scopes are convenience functionality for slog-rs to free user from manually passing Logger objects around.

Set of macros is also provided as an alternative to original slog crate macros, for logging directly to Logger of the current logging scope.

Set global logger upfront

Warning: Since slog-scope version 4.0.0, slog-scope defaults to panicking on logging if no scope or global logger was set. Because of it, it is advised to always set a global logger upfront with set_global_logger.

Using slog-scope as a part of API is not advised

Part of a slog logging philosophy is ability to freely express logging contexts according to logical structure, rather than callstack structure. By using logging scopes the logging context is tied to code flow again, which is less expressive.

It is generally advised NOT to use slog_scope in libraries. Read more in slog-rs FAQ

#[macro_use(slog_o, slog_info, slog_log, slog_record, slog_record_static, slog_b, slog_kv)]
extern crate slog;
#[macro_use]
extern crate slog_scope;
extern crate slog_term;

use slog::Drain;

fn foo() {
    slog_info!(slog_scope::logger(), "foo");
    info!("foo"); // Same as above, but more ergonomic and a bit faster
                  // since it uses `with_logger`
}

fn main() {
    let plain = slog_term::PlainSyncDecorator::new(std::io::stdout());
    let log = slog::Logger::root(
        slog_term::FullFormat::new(plain)
        .build().fuse(), slog_o!()
    );

    // Make sure to save the guard, see documentation for more information
    let _guard = slog_scope::set_global_logger(log);
    slog_scope::scope(&slog_scope::logger().new(slog_o!("scope" => "1")),
        || foo()
    );
}

Macros

• crit
  Log a critical level message using current scope logger
• debug
  Log a debug level message using current scope logger
• error
  Log a error level message using current scope logger
• info
  Log a info level message using current scope logger
• slog_crit
  Log critical level record (alias)
• slog_debug
  Log debug level record (alias)
• slog_error
  Log error level record
• slog_info
  Log info level record (alias)
• slog_trace
  Log trace level record (alias)
• slog_warn
  Log warning level record (alias)
• trace
  Log a trace level message using current scope logger
• warn
  Log a warning level message using current scope logger

Structs

• GlobalLoggerGuard
  Guard resetting global logger

Functions

• logger
  Access the Logger for the current logging scope
• scope
  Execute code in a logging scope
• set_global_logger
  Set global Logger that is returned by calls like logger() outside of any logging scope.
• with_logger
  Access the Logger for the current logging scope