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//! The central struct designed for managing logging tasks
use super::define::*;
use super::record::*;
use super::source::*;
use super::plugin::*;
use super::target::*;
/// The Logger
///
/// Responsible for setting the log level, spawning log records, and managing plugins, targets,
/// and all other logging functionalities.
pub struct Logger {
barrier: Level, // log level filter
records: Mutex<Vec<Record>>, // records pool
plugins: Vec<Box<dyn Plugin>>, // middlewares
targets: Vec<Box<dyn Target>>, // output targets
default: Option<&'static dyn Target>, // default output
}
impl Logger {
/// Create a logger with a default static target
///
/// Note that the default target can't be deleted.
///
/// ```
/// let logger = logkit::Logger::new(Some(&logkit::StderrTarget));
/// logkit::set_default_logger(logger);
/// ```
pub const fn new(default: Option<&'static dyn Target>) -> Self {
Self {
barrier: LEVEL_TRACE,
records: Mutex::new(vec![]),
plugins: vec![],
targets: vec![],
default,
}
}
/// Create a logger without output target
///
/// ```
/// logkit::set_default_logger(logkit::Logger::nop());
/// ```
pub const fn nop() -> Self {
Self::new(None)
}
/// Get current log level
///
/// ```
/// assert_eq!(logkit::default_logger().level(), logkit::LEVEL_TRACE);
/// ```
#[inline]
pub fn level(&self) -> Level {
self.barrier
}
/// Set current log level
///
/// ```
/// let mut logger = logkit::Logger::new(Some(&logkit::StderrTarget));
/// logger.limit(logkit::LEVEL_INFO);
/// logkit::set_default_logger(logger);
/// assert_eq!(logkit::default_logger().level(), logkit::LEVEL_INFO);
/// ```
pub fn limit(&mut self, level: Level) -> &mut Self {
self.barrier = level;
self
}
/// Check if the log level is equal to or higher than the limit
///
/// ```
/// let mut logger = logkit::Logger::new(Some(&logkit::StderrTarget));
/// logger.limit(logkit::LEVEL_INFO);
/// logkit::set_default_logger(logger);
///
/// assert_eq!(logkit::default_logger().allow(logkit::LEVEL_TRACE), false);
/// assert_eq!(logkit::default_logger().allow(logkit::LEVEL_DEBUG), false);
/// assert_eq!(logkit::default_logger().allow(logkit::LEVEL_INFO), true);
/// assert_eq!(logkit::default_logger().allow(logkit::LEVEL_WARN), true);
/// assert_eq!(logkit::default_logger().allow(logkit::LEVEL_ERROR), true);
/// ```
#[inline]
pub fn allow(&self, level: Level) -> bool {
level >= self.barrier
}
/// Install a plugin for records
///
/// A plugin acts as middleware for logs. For more details, refer to `plugin.rs`.
///
/// ```
/// let mut logger = logkit::Logger::new(Some(&logkit::StderrTarget));
/// logger.mount(logkit::TimePlugin::from_millis());
/// logger.mount(logkit::LevelPlugin);
/// logkit::set_default_logger(logger);
/// ```
pub fn mount(&mut self, plugin: impl Plugin) -> &mut Self {
self.plugins.push(Box::new(plugin));
self
}
/// Uninstall a plugin
///
/// ```
/// let mut logger = logkit::Logger::new(Some(&logkit::StderrTarget));
/// logger.mount(logkit::LevelPlugin);
/// logger.unmount(|t| t.as_any().downcast_ref::<logkit::LevelPlugin>().is_some());
/// logkit::set_default_logger(logger);
/// ```
pub fn unmount(&mut self, del: impl Fn(&dyn Plugin) -> bool) -> &mut Self {
self.plugins.retain(|plugin| !del(plugin.as_ref()));
self
}
/// Get all plugins
///
/// ```
/// let mut logger = logkit::Logger::new(Some(&logkit::StderrTarget));
/// logger.mount(logkit::LevelPlugin);
/// assert_eq!(logger.plugins().len(), 1);
///
/// logger.unmount(|t| t.as_any().downcast_ref::<logkit::LevelPlugin>().is_some());
/// assert_eq!(logger.plugins().len(), 0);
/// ```
pub fn plugins(&self) -> &Vec<Box<dyn Plugin>> {
&self.plugins
}
/// Add a output target for records
///
/// Multiple targets are supported, allowing you to output a single record to various places.
///
/// ```
/// let mut logger = logkit::Logger::new(None);
/// logger.route(logkit::StderrTarget);
/// logkit::set_default_logger(logger);
/// ```
pub fn route(&mut self, target: impl Target) -> &mut Self {
self.targets.push(Box::new(target));
self
}
/// Remove a output target
///
/// ```
/// let mut logger = logkit::Logger::new(None);
/// logger.route(logkit::StderrTarget);
/// logger.unroute(|t| t.as_any().downcast_ref::<logkit::StderrTarget>().is_some());
/// logkit::set_default_logger(logger);
/// ```
pub fn unroute(&mut self, del: impl Fn(&dyn Target) -> bool) -> &mut Self {
self.targets.retain(|target| !del(target.as_ref()));
self
}
/// Get all targets, except default target
///
/// ```
/// let mut logger = logkit::Logger::new(Some(&logkit::StderrTarget));
/// assert_eq!(logger.targets().len(), 0); // no default target
///
/// logger.route(logkit::StdoutTarget);
/// assert_eq!(logger.targets().len(), 1);
///
/// logger.unroute(|t| t.as_any().downcast_ref::<logkit::StdoutTarget>().is_some());
/// assert_eq!(logger.targets().len(), 0);
/// ```
pub fn targets(&self) -> &Vec<Box<dyn Target>> {
&self.targets
}
/// Create a new log record
///
/// Internally, each log is represented by a record, which contains level information and
/// a cached buffer. You can append numerous fields to a record. The println-like message is
/// also treated as a normal field with the key named `msg`.
///
/// ```
/// let logger = logkit::Logger::new(Some(&logkit::StderrTarget));
///
/// if let Some(mut record) = logger.spawn(logkit::LEVEL_TRACE, logkit::source!()) {
/// record.append("hello", &"world");
/// record.finish();
/// assert_eq!(String::from_utf8_lossy(record.buffer().as_slice()), "{\"hello\":\"world\"}\n")
/// }
/// ```
#[inline]
pub fn spawn(&self, level: Level, source: Source) -> Option<Record> {
if !self.allow(level) {
return None;
}
let record = match self.records.lock() {
Ok(mut obj) => obj.pop(),
Err(_) => return None
};
let mut record = match record {
None => Record::new(level, source),
Some(val) => Record::set(val, level, source),
};
for plugin in &self.plugins {
if !plugin.pre(&mut record) {
self.reuse(record);
return None;
}
}
Some(record)
}
/// Finish and output a record
///
/// The `post` method of plugins will be called. If you wish to prevent output to targets,
/// simply return `false`. Once the `finish` method is invoked, the record will be directed
/// to all installed targets for output.
///
/// Note that the default target is always invoked first.
///
/// ```
/// let logger = logkit::Logger::new(Some(&logkit::StderrTarget));
///
/// if let Some(mut record) = logger.spawn(logkit::LEVEL_TRACE, logkit::source!()) {
/// record.append("msg", &"this log will be directed to stderr");
/// logger.flush(record);
/// }
/// ```
#[inline]
pub fn flush(&self, mut record: Record) {
for plugin in &self.plugins {
if !plugin.post(&mut record) {
self.reuse(record);
return;
}
}
record.finish();
if let Some(target) = self.default {
target.write(record.buffer());
}
for target in &self.targets {
target.write(record.buffer());
}
self.reuse(record);
}
/// Places the record back into the object pool for reuse
///
/// The `flush` method calls this function automatically, so typically you don't need to
/// invoke it manually.
#[inline]
pub fn reuse(&self, record: Record) {
if let Ok(mut obj) = self.records.lock() {
obj.push(record)
}
}
}