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#[cfg(feature = "specfile")] use notify::{watcher, DebouncedEvent, RecursiveMode, Watcher}; #[cfg(feature = "specfile")] use std::sync::mpsc::channel; #[cfg(feature = "specfile")] use std::time::Duration; #[cfg(feature = "specfile")] use std::thread; use FormatFunction; use flexi_logger::{reconfiguration_handle, FlexiLogger, LogSpec}; use {formats, FlexiLoggerError, LogSpecification}; use log; use primary_writer::PrimaryWriter; use ReconfigurationHandle; use std::collections::HashMap; use std::path::Path; use std::sync::{Arc, RwLock}; use writers::{FileLogWriter, FileLogWriterBuilder, LogWriter}; /// The standard entry-point for using `flexi_logger`. /// /// Create a Logger with your desired (initial) loglevel-specification /// /// * by specifying it programmatically as a String, /// using [`Logger::with_str()`](struct.Logger.html#method.with_str), /// * or by expecting a String in the environment, /// using [`Logger::with_env()`](struct.Logger.html#method.with_env), /// * or by combining both options, /// using [`Logger::with_env_or_str()`](struct.Logger.html#method.with_env_or_str), /// * or by providing an explicitly built `LogSpecification`, /// using [`Logger::with()`](struct.Logger.html#method.with), /// /// then use `Logger`'s configuration methods, /// and finally call [start()](struct.Logger.html#method.start), /// or [`start_reconfigurable()`](struct.Logger.html#method.start_reconfigurable), /// or [`start_with_specfile()`](struct.Logger.html#method.start_with_specfile). /// /// ## Examples /// /// ### Use defaults only /// /// If you initialize `flexi_logger` like this, it behaves like `env_logger`: /// /// ```rust /// use flexi_logger::Logger; /// /// Logger::with_env().start().unwrap(); /// ``` /// /// ### Write to files, use a detailed log-line format that contains the module and line number /// /// Here we configure `flexi_logger` to write log entries with /// time and location info into a log file in folder "`log_files`", /// and we provide the loglevel-specification programmatically, as String, but allow it /// to be overridden by the environment variable `RUST_LOG`: /// /// ``` /// use flexi_logger::{Logger,opt_format}; /// /// Logger::with_env_or_str("myprog=debug, mylib=warn") /// .log_to_file() /// .directory("log_files") /// .format(opt_format) /// .start() /// .unwrap_or_else(|e|{panic!("Logger initialization failed with {}",e)}); /// ``` /// pub struct Logger { spec: LogSpecification, log_to_file: bool, duplicate_error: bool, duplicate_info: bool, format: FormatFunction, flwb: FileLogWriterBuilder, other_writers: HashMap<String, Box<LogWriter>>, } /// Simple methods for influencing the behavior of the Logger. impl Logger { /// Creates a Logger that you provide with an explicit LogSpecification. /// By default, logs are written with `default_format` to `stderr`. pub fn with(logspec: LogSpecification) -> Logger { Logger { spec: logspec, duplicate_error: false, log_to_file: false, duplicate_info: false, format: formats::default_format, flwb: FileLogWriter::builder(), other_writers: HashMap::<String, Box<LogWriter>>::new(), } } /// Creates a Logger that reads the LogSpecification from a String or &str. /// [See LogSpecification](struct.LogSpecification.html) for the syntax. pub fn with_str<S: AsRef<str>>(s: S) -> Logger { Logger::with(LogSpecification::parse(s.as_ref())) } /// Creates a Logger that reads the LogSpecification from the environment variable RUST_LOG. pub fn with_env() -> Logger { Logger::with(LogSpecification::env()) } /// Creates a Logger that reads the LogSpecification from the environment variable RUST_LOG, /// or derives it from the given String, if RUST_LOG is not set. pub fn with_env_or_str<S: AsRef<str>>(s: S) -> Logger { Logger::with(LogSpecification::env_or_parse(s)) } /// Makes the logger write all logs to a file, rather than to stderr. /// /// The default pattern for the filename is '\<program_name\>\_\<date\>\_\<time\>.\<suffix\>', /// e.g. `myprog_2015-07-08_10-44-11.log`. pub fn log_to_file(mut self) -> Logger { self.log_to_file = true; self } /// Makes the logger print an info message to stdout with the name of the logfile /// when a logfile is opened for writing. pub fn print_message(mut self) -> Logger { self.flwb = self.flwb.print_message(); self } /// Makes the logger write all logged error messages additionally to stdout. pub fn duplicate_error(mut self) -> Logger { self.duplicate_error = true; self } /// Makes the logger write all logged error, warning, and info messages additionally to stdout. pub fn duplicate_info(mut self) -> Logger { self.duplicate_info = true; self } /// Makes the logger use the provided format function for the log entries, /// rather than [formats::default_format](fn.default_format.html). /// /// You can either choose between some predefined variants, /// ```default_format```, ```opt_format```, ```detailed_format```, ```with_thread```, /// or you create and use your own format function /// with the signature ```fn(&Record) -> String```. pub fn format(mut self, format: FormatFunction) -> Logger { self.format = format; self } /// Specifies a folder for the log files. /// /// This parameter only has an effect if `log_to_file()` is used, too. /// If the specified folder does not exist, the initialization will fail. /// By default, the log files are created in the folder where the program was started. pub fn directory<S: Into<String>>(mut self, directory: S) -> Logger { self.flwb = self.flwb.directory(directory); self } /// Specifies a suffix for the log files. /// /// This parameter only has an effect if `log_to_file()` is used, too. pub fn suffix<S: Into<String>>(mut self, suffix: S) -> Logger { self.flwb = self.flwb.suffix(suffix); self } /// Makes the logger not include a timestamp into the names of the log files. /// /// This option only has an effect if `log_to_file()` is used, too. pub fn suppress_timestamp(mut self) -> Logger { self.flwb = self.flwb.suppress_timestamp(); self } /// By default, the log file will grow indefinitely. /// With this option, when the log file reaches or exceeds the specified file size, /// the file will be closed and a new file will be opened. /// Also the filename pattern changes - instead of the timestamp, /// a serial number is included into the filename. /// /// This option only has an effect if `log_to_file()` is used, too. pub fn rotate_over_size(mut self, rotate_over_size: usize) -> Logger { self.flwb = self.flwb.rotate_over_size(rotate_over_size); self } /// Makes the logger append to the specified output file, if it exists already; /// by default, the file would be truncated. /// /// This option only has an effect if `log_to_file()` is used, too. /// This option will hardly make an effect if `suppress_timestamp()` is not used. pub fn append(mut self) -> Logger { self.flwb = self.flwb.append(); self } /// The specified String is added to the log file name after the program name. /// /// This option only has an effect if `log_to_file()` is used, too. pub fn discriminant<S: Into<String>>(mut self, discriminant: S) -> Logger { self.flwb = self.flwb.discriminant(discriminant); self } /// The specified String will be used on linux systems to create in the current folder /// a symbolic link to the current log file. /// /// This option only has an effect if `log_to_file()` is used, too. pub fn create_symlink<S: Into<String>>(mut self, symlink: S) -> Logger { self.flwb = self.flwb.create_symlink(symlink); self } /// Registers a LogWriter implementation under the given target name. /// /// The target name should not start with an underscore. /// /// See [the module documentation of `writers`](writers/index.html). pub fn add_writer<S: Into<String>>(mut self, name: S, writer: Box<LogWriter>) -> Logger { self.other_writers.insert(name.into(), writer); self } /// Consumes the Logger object and initializes the flexi_logger. /// If started this way, the logger cannot be influenced anymore /// while the program is running. pub fn start(mut self) -> Result<(), FlexiLoggerError> { let max = self.spec .module_filters() .iter() .map(|d| d.level_filter) .max() .unwrap_or(log::LevelFilter::Off); log::set_boxed_logger(Box::new(FlexiLogger::new( LogSpec::STATIC(self.spec), Arc::new(if self.log_to_file { self.flwb = self.flwb.format(self.format); PrimaryWriter::file( self.duplicate_error, self.duplicate_info, self.flwb.instantiate()?, ) } else { PrimaryWriter::stderr(self.format) }), self.other_writers, )))?; log::set_max_level(max); Ok(()) } /// Consumes the Logger object and initializes the flexi_logger in a way that /// subsequently the log specification can be exchanged dynamically. /// /// The resulting logger is still fast, but measurable slower for those log-calls (trace!() etc) /// that are on a deeper level than the deepest level in the LogSpecification. /// This is because the Log crate has an optimization for returning very fast from deep-level /// log calls, but the deepest level needs be given at initialization and cannot be updated /// later. /// /// Here is the output from a benchmark test, runnning on a windows laptop: /// /// ```text /// 1 PS C:\projects\flexi_logger> cargo bench --bench bench_standard -- --nocapture /// 2 Finished release [optimized] target(s) in 0.4 secs /// 3 Running target\release\deps\bench_standard-20539c2be6d4f2e0.exe /// 4 /// 5 running 4 tests /// 6 test b10_no_logger_active ... bench: 118 ns/iter (+/- 19) /// 7 test b20_initialize_logger ... bench: 0 ns/iter (+/- 0) /// 8 test b30_relevant_logs ... bench: 291,436 ns/iter (+/- 44,658) /// 9 test b40_suppressed_logs ... bench: 123 ns/iter (+/- 5) /// 10 /// 11 test result: ok. 0 passed; 0 failed; 0 ignored; 4 measured; 0 filtered out /// 12 /// 13 PS C:\projects\flexi_logger> cargo bench --bench bench_reconfigurable -- --nocapture /// 14 Finished release [optimized] target(s) in 0.4 secs /// 15 Running target\release\deps\bench_reconfigurable-2e292a8d5c887d0d.exe /// 16 /// 17 running 4 tests /// 18 test b10_no_logger_active ... bench: 130 ns/iter (+/- 37) /// 19 test b20_initialize_logger ... bench: 0 ns/iter (+/- 0) /// 20 test b30_relevant_logs ... bench: 301,092 ns/iter (+/- 87,452) /// 21 test b40_suppressed_logs ... bench: 3,482 ns/iter (+/- 339) /// 22 /// 23 test result: ok. 0 passed; 0 failed; 0 ignored; 4 measured; 0 filtered out /// ``` /// /// It shows that logging is fastest when no logger is active (lines 6 and 18). /// And it is just as fast when the above-mentioned optimization kicks in (line 9). /// /// Logging has measurable costs when logs are really written (line 8 and 20), independent /// of the reconfigurability feature of the flexi_logger. /// /// The measurable, but still in most cases not important, price for reconfigurability /// can be seen by comparing lines 9 and 21. /// pub fn start_reconfigurable(mut self) -> Result<ReconfigurationHandle, FlexiLoggerError> { let spec = Arc::new(RwLock::new(self.spec)); let primary_writer = Arc::new(if self.log_to_file { self.flwb = self.flwb.format(self.format); PrimaryWriter::file( self.duplicate_error, self.duplicate_info, self.flwb.instantiate()?, ) } else { PrimaryWriter::stderr(self.format) }); let flexi_logger = FlexiLogger::new( LogSpec::DYNAMIC(Arc::clone(&spec)), Arc::clone(&primary_writer), self.other_writers, ); log::set_boxed_logger(Box::new(flexi_logger))?; // no optimization possible, because the spec is dynamic, but max is not: log::set_max_level(log::LevelFilter::Trace); Ok(reconfiguration_handle(spec, primary_writer)) } /// Uses the spec that was given to the factory method (`Logger::with()` etc) /// as initial spec and then tries to read the logspec from a file. /// /// If the file does not exist, `flexi_logger` creates the file and fills it /// with the initial spec (and in the respective file format, of course). /// /// ## Feature dependency /// /// The implementation of this configuration method uses some additional crates /// that you might not want to depend on with your program if you don't use this functionality. /// For that reason the method requires to activate the /// `specfile` feature. See `flexi_logger`'s [usage](index.html#usage) section for details. /// /// The method panics if called when the "specfile" feature is not used. /// /// ## Usage /// /// A logger initialization like /// /// ```ignore /// use flexi_logger::Logger; /// Logger::with_str("info")/*...*/.start_with_specfile("logspecification.toml"); /// ``` /// /// will create the file `logspecification.toml` (if it does not yet exist) with this content: /// /// ```toml /// ### Optional: Default log level /// global_level = 'info' /// ### Optional: specify a regular expression to suppress all messages that don't match /// #global_pattern = 'foo' /// /// ### Specific log levels per module are optionally defined in this section /// [modules] /// #'mod1' = 'warn' /// #'mod2' = 'debug' /// #'mod2::mod3' = 'trace' /// ``` /// /// You can subsequently edit and modify the file according to your needs, /// while the program is running, and it will immediately take your changes into account. /// /// Currently only toml-files are supported, the file suffix thus must be `.toml`. /// /// The initial spec remains valid if the file cannot be read. /// /// If you update the specfile subsequently while the program is running, `flexi_logger` /// re-reads it automatically and adapts its behavior according to the new content. /// If the file cannot be read anymore, e.g. because the format is not correct, the /// previous logspec remains active. /// If the file is corrected subsequently, the log spec update will work again. /// pub fn start_with_specfile<P: AsRef<Path>>(self, specfile: P) -> Result<(), FlexiLoggerError> { if cfg!(feature = "specfile") { #[cfg(feature = "specfile")] { self.start_with_specfile_impl(specfile)?; } } else { let _p = specfile; panic!("Logger.start_with_specfile() requires the feature \"specfile\""); } Ok(()) } #[cfg(feature = "specfile")] fn start_with_specfile_impl<P: AsRef<Path>>(self, specfile: P) -> Result<(), FlexiLoggerError> { let specfile = specfile.as_ref().to_owned(); self.spec.ensure_specfile_is_valid(&specfile)?; let mut handle = self.start_reconfigurable()?; // now setup fs notification to automatically reread the file, and initialize from the file thread::Builder::new().spawn(move || { // Create a channel to receive the events. let (tx, rx) = channel(); // Create a watcher object, delivering debounced events let mut watcher = match watcher(tx, Duration::from_millis(800)) { Ok(w) => w, Err(e) => { error!("watcher() failed with {:?}", e); return; } }; // watch the spec file match watcher.watch(&specfile, RecursiveMode::NonRecursive) { Err(e) => { error!( "watcher.watch() failed for the log specification file {:?}, caused by {:?}", specfile, e ); ::std::process::exit(-1); } Ok(_) => { // initial read of the file: if that fails, just print an error and continue match LogSpecification::file(&specfile) { Ok(spec) => handle.set_new_spec(spec), Err(e) => error!("Can't read the log specification file, due to {:?}", e), } loop { match rx.recv() { Ok(DebouncedEvent::Write(_)) => { debug!("Got Write event"); match LogSpecification::file(&specfile) { Ok(spec) => handle.set_new_spec(spec), Err(e) => eprintln!( "Continuing with current log specification \ because the log specification file is not readable, \ due to {:?}", e ), } } Ok(_event) => trace!("ignoring event {:?}", _event), Err(e) => error!("watch error: {:?}", e), } } } } })?; Ok(()) } } /// Alternative set of methods to control the behavior of the Logger. /// Use these methods when you want to control the settings flexibly, /// e.g. with commandline arguments via `docopts` or `clap`. impl Logger { /// With true, makes the logger write all logs to a file, otherwise to stderr. pub fn o_log_to_file(mut self, log_to_file: bool) -> Logger { self.log_to_file = log_to_file; self } /// With true, makes the logger print an info message to stdout, each time /// when a new file is used for log-output. pub fn o_print_message(mut self, print_message: bool) -> Logger { self.flwb = self.flwb.o_print_message(print_message); self } /// With true, makes the logger write all logged error messages additionally to stdout. pub fn o_duplicate_error(mut self, duplicate_error: bool) -> Logger { self.duplicate_error = duplicate_error; self } /// With true, makes the logger write all logged error, warning, /// and info messages additionally to stdout. pub fn o_duplicate_info(mut self, duplicate_info: bool) -> Logger { self.duplicate_info = duplicate_info; self } /// Specifies a folder for the log files. /// /// This parameter only has an effect if `log_to_file` is set to true. /// If the specified folder does not exist, the initialization will fail. /// With None, the log files are created in the folder where the program was started. pub fn o_directory<S: Into<String>>(mut self, directory: Option<S>) -> Logger { self.flwb = self.flwb.o_directory(directory); self } /// With true, makes the logger include a timestamp into the names of the log files. /// /// This parameter only has an effect if `log_to_file` is set to true. pub fn o_timestamp(mut self, timestamp: bool) -> Logger { self.flwb = self.flwb.o_timestamp(timestamp); self } /// This option only has an effect if `log_to_file` is set to true. /// /// By default, and with None, the log file will grow indefinitely. /// If a size is set, when the log file reaches or exceeds the specified size, /// the file will be closed and a new file will be opened. /// Also the filename pattern changes - instead of the timestamp a serial number /// is included into the filename. pub fn o_rotate_over_size(mut self, rotate_over_size: Option<usize>) -> Logger { self.flwb = self.flwb.o_rotate_over_size(rotate_over_size); self } /// This option only has an effect if `log_to_file` is set to true. /// /// If append is set to true, makes the logger append to the specified output file, if it exists. /// By default, or with false, the file would be truncated. /// /// This option will hardly make an effect if `suppress_timestamp()` is not used. pub fn o_append(mut self, append: bool) -> Logger { self.flwb = self.flwb.o_append(append); self } /// This option only has an effect if `log_to_file` is set to true. /// /// The specified String is added to the log file name. pub fn o_discriminant<S: Into<String>>(mut self, discriminant: Option<S>) -> Logger { self.flwb = self.flwb.o_discriminant(discriminant); self } /// This option only has an effect if `log_to_file` is set to true. /// /// If a String is specified, it will be used on linux systems to create in the current folder /// a symbolic link with this name to the current log file. pub fn o_create_symlink<S: Into<String>>(mut self, symlink: Option<S>) -> Logger { self.flwb = self.flwb.o_create_symlink(symlink); self } }