Add logger with logging library

src/main.rs

@@ -1,7 +1,8 @@
 #[macro_use] extern crate clap;
+#[macro_use] extern crate log;
 
 use cli::Config;
-use runtime::Runtime;
+use runtime::{ImagLogger, Runtime};
 use clap::App;
 
 mod cli;
@@ -10,10 +11,12 @@ mod module;
 mod storage;
 
 fn main() {
+    let early_logger = ImagLogger::early().unwrap();
     let yaml = load_yaml!("../etc/cli.yml");
     let app = App::from_yaml(yaml);
     let mut config = Config::new(app);
 
+    let logger = ImagLogger::init(&config);
     let rt = Runtime::new(config);
 
     println!("Hello, world!");

src/runtime.rs

@@ -1,7 +1,59 @@
+extern crate log;
+
 pub use cli::Config;
 
 use std::io::stderr;
 use std::io::Write;
+use log::{LogRecord, LogLevel, LogLevelFilter, LogMetadata, SetLoggerError};
+
+pub struct ImagLogger {
+    lvl: LogLevel,
+}
+
+impl ImagLogger {
+
+    pub fn new(lvl: LogLevel) -> ImagLogger {
+        ImagLogger {
+            lvl: lvl,
+        }
+    }
+
+    pub fn early() -> Result<(), SetLoggerError> {
+        ImagLogger::init_logger(LogLevelFilter::Error)
+    }
+
+    pub fn init(config: &Config) -> Result<(), SetLoggerError> {
+        if config.is_debugging() {
+            ImagLogger::init_logger(LogLevelFilter::Debug)
+        } else if config.is_verbose() {
+            ImagLogger::init_logger(LogLevelFilter::Info)
+        } else {
+            ImagLogger::init_logger(LogLevelFilter::Error)
+        }
+
+    }
+
+    fn init_logger(lvlflt : LogLevelFilter) -> Result<(), SetLoggerError> {
+        log::set_logger(|max_log_lvl| {
+            max_log_lvl.set(lvlflt);
+            Box::new(ImagLogger::new(lvlflt.to_log_level().unwrap()))
+        })
+    }
+
+}
+
+impl log::Log for ImagLogger {
+
+    fn enabled(&self, metadata: &LogMetadata) -> bool {
+        metadata.level() <= self.lvl
+    }
+
+    fn log(&self, record: &LogRecord) {
+        if self.enabled(record.metadata()) {
+            println!("[{}]: {}", record.level(), record.args());
+        }
+    }
+}
 
 pub struct Runtime<'a> {
     pub config : Config<'a>,