slog-try

Convenience macros for logging with an optional slog Logger.

Required dependencies

Add slog and slog-try as a dependency in your Cargo.toml file.

[dependencies]
slog = "^2"
slog-try = "^0.2"

Project setup

Add the new dependencies as external crates into the main.rs or lib.rs file of your project:

#[macro_use]
extern crate slog;
#[macro_use]
extern crate slog_try;

Usage example

Consider HasOptLogger, a data strcuture with an optionally attachable logger:

#[derive(Default)]
struct HasOptLogger {
    logger: Option<Logger>,
}

The macros contained in slog-try encapsulate the required boilerplate to use this logger without verifying whether the optional field actually contains a logger or not:

let mut opt_logger= HasOptLogger { logger: None };

// Try to log even if no logger exist
try_info!(opt_logger.logger, "You won't see me output.  The logger is None."; "opt" => "None");
try_info!(opt_logger.logger, #"imatag", "You won't see me output.  The logger is None."; "opt" => "None");

// Setup a `Logger`
let plain = slog_term::PlainSyncDecorator::new(::std::io::stdout());
let logger = Logger::root(slog_term::FullFormat::new(plain)
    .build()
    .fuse(), o!("surname" => "Lava"));

opt_logger.logger = Some(logger);

// Call again with the new attached logger
try_info!(opt_logger.logger, "You will see me output!"; "opt" => "Some");
try_info!(opt_logger.logger, #"imatag", "You will see me output!"; "opt" => "Some");