slog-rs logging (#171)

* added global slog instance, changed all logging macro formats to include logger instance
* adding configuration to logging, allowing for multiple log outputs
* updates to test, changes to build docs
* rustfmt
* moving logging functions into util crate

util/src/lib.rs

@@ -12,9 +12,35 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-/// Various low-level utilities that factor Rust patterns that are frequent
-/// within the grin codebase.
+//! Logging, as well as various low-level utilities that factor Rust 
+//! patterns that are frequent within the grin codebase.
 
+#![deny(non_upper_case_globals)]
+#![deny(non_camel_case_types)]
+#![deny(non_snake_case)]
+#![deny(unused_mut)]
+#![warn(missing_docs)]
+
+#[macro_use]
+extern crate slog;
+extern crate slog_term;
+extern crate slog_async;
+
+#[macro_use]
+extern crate lazy_static;
+
+extern crate serde;
+#[macro_use]
+extern crate serde_derive;
+
+// Logging related
+pub mod logger;
+pub use logger::{LOGGER, init_logger};
+
+pub mod types;
+pub use types::LoggingConfig;
+
+// other utils
 use std::cell::{RefCell, Ref};
 #[allow(unused_imports)]
 use std::ops::Deref;
@@ -22,12 +48,13 @@ use std::ops::Deref;
 mod hex;
 pub use hex::*;
 
-// Encapsulation of a RefCell<Option<T>> for one-time initialization after
-// construction. This implementation will purposefully fail hard if not used
-// properly, for example if it's not initialized before being first used
-// (borrowed).
+/// Encapsulation of a RefCell<Option<T>> for one-time initialization after
+/// construction. This implementation will purposefully fail hard if not used
+/// properly, for example if it's not initialized before being first used
+/// (borrowed).
 #[derive(Clone)]
 pub struct OneTime<T> {
+	/// inner
 	inner: RefCell<Option<T>>,
 }
 

util/src/logger.rs

@@ -0,0 +1,87 @@
+// Copyright 2017 The Grin Developers
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Logging wrapper to be used throughout all crates in the workspace
+use std::fs::OpenOptions;
+use std::sync::Mutex;
+use slog::{Logger, Drain, Level, LevelFilter, Duplicate, Discard};
+use slog_term;
+use slog_async;
+
+use types::{LogLevel, LoggingConfig};
+
+fn convert_log_level(in_level:&LogLevel)->Level{
+	match *in_level {
+		LogLevel::Info => Level::Info,
+		LogLevel::Critical => Level::Critical,
+		LogLevel::Warning => Level::Warning,
+		LogLevel::Debug => Level::Debug,
+		LogLevel::Trace => Level::Trace,
+		LogLevel::Error => Level::Error,
+	}
+}
+
+lazy_static! {
+	/// Static Logging configuration, should only be set once, before first logging call
+	static ref LOGGING_CONFIG: Mutex<LoggingConfig> = Mutex::new(LoggingConfig::default());
+	/// And a static reference to the logger itself, accessible from all crates
+	pub static ref LOGGER: Logger = {
+		let config = LOGGING_CONFIG.lock().unwrap();
+		let slog_level_stdout = convert_log_level(&config.stdout_log_level);
+		let slog_level_file = convert_log_level(&config.file_log_level);
+
+		//Terminal output drain
+		let terminal_decorator = slog_term::TermDecorator::new().build();
+		let terminal_drain = slog_term::FullFormat::new(terminal_decorator).build().fuse();
+		let terminal_drain = LevelFilter::new(terminal_drain, slog_level_stdout).fuse();
+		let mut terminal_drain = slog_async::Async::new(terminal_drain).build().fuse();
+
+		if !config.log_to_stdout {
+			terminal_drain = slog_async::Async::new(Discard{}).build().fuse();
+		}
+		
+		let mut file_drain_final = slog_async::Async::new(Discard{}).build().fuse();
+
+		if config.log_to_file {
+			//File drain
+			let file = OpenOptions::new()
+				.create(true)
+				.write(true)
+				.append(config.log_file_append)
+				.truncate(false)
+				.open(&config.log_file_path)
+				.unwrap();
+
+			let file_decorator = slog_term::PlainDecorator::new(file);
+			let file_drain = slog_term::FullFormat::new(file_decorator).build().fuse();
+			let file_drain = LevelFilter::new(file_drain, slog_level_file).fuse();
+			file_drain_final = slog_async::Async::new(file_drain).build().fuse();
+		}
+
+		//Compose file and terminal drains
+		let composite_drain = Duplicate::new(terminal_drain, file_drain_final).fuse();
+
+		let log = Logger::root(composite_drain, o!());
+		log
+  };
+}
+
+/// Initialises the logger with the given configuration
+
+pub fn init_logger(config:Option<LoggingConfig>){
+	if let Some(c) = config {
+		let mut config_ref=LOGGING_CONFIG.lock().unwrap();
+		*config_ref=c.clone();
+	}
+	
+}

util/src/types.rs

@@ -0,0 +1,62 @@
+// Copyright 2017 The Grin Developers
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Logging configuration types
+
+/// Log level types, as slog's don't implement serialize
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum LogLevel {
+	/// Critical
+	Critical,
+	/// Error
+	Error,
+	/// Warning
+	Warning,
+	/// Info
+	Info,
+	/// Debug
+	Debug,
+	/// Trace
+	Trace,
+}
+
+/// Logging config
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct LoggingConfig {
+	/// whether to log to stdout
+	pub log_to_stdout: bool,
+	/// logging level for stdout
+	pub stdout_log_level: LogLevel,
+	/// whether to log to file
+	pub log_to_file: bool,
+	/// log file level
+	pub file_log_level: LogLevel,
+	/// Log file path
+	pub log_file_path: String,
+	/// Whether to append to log or replace
+	pub log_file_append: bool,
+}
+
+impl Default for LoggingConfig {
+	fn default() -> LoggingConfig {
+		LoggingConfig {
+			log_to_stdout: true,
+			stdout_log_level: LogLevel::Debug,
+			log_to_file: false,
+			file_log_level: LogLevel::Trace,
+			log_file_path: String::from("grin.log"),
+			log_file_append: false,
+		}
+	}
+}