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//! [](https://github.com/nonconvextech/ftlog/actions)
//! 
//! [](https://crates.io/crates/ftlog)
//! [](https://docs.rs/ftlog)
//!
//! Logging is affected by the disk IO and pipe system call.
//! Sequential log calls can be a bottleneck in scenarios where low
//! latency is critical (e.g., high-frequency trading).
//!
//! `ftlog` mitigates this bottleneck by sending messages to a dedicated logger
//! thread and computing as little as possible in the main/worker thread.
//!
//! `ftlog` can improve log performance in main/worker thread a few times over. See
//! performance for details.
//!
//!
//! # Usage
//!
//! Add to your `Cargo.toml`:
//!
//! ```toml
//! ftlog = "0.2"
//! ```
//!
//! Configure and initialize ftlog at the start of your `main` function:
//! ```
//! // ftlog re-export `log`'s macros, so no need to add `log` to dependencies
//! use ftlog::appender::FileAppender;
//! use ftlog::{debug, trace};
//! use log::{error, info, warn};
//!
//! // minimal configuration with default setting
//! ftlog::builder().try_init().unwrap();
//!
//! trace!("Hello world!");
//! debug!("Hello world!");
//! info!("Hello world!");
//! warn!("Hello world!");
//! error!("Hello world!");
//!
//! // When main thread is done, ftlog worker thread may be busy printing messages.
//! // Manually flush log output, otherwise messages in memory yet might lost
//! log::logger().flush();
//! ```
//!
//! A more complicated but feature rich usage:
//!
//! ```rust,no_run
//! use ftlog::{
//! appender::{Duration, FileAppender, Period},
//! FtLogFormatter, LevelFilter,
//! };
//!
//! let time_format = time::format_description::parse_owned::<1>(
//! "[year]-[month]-[day] [hour]:[minute]:[second].[subsecond digits:6]",
//! )
//! .unwrap();
//! // configurate logger
//! let logger = ftlog::builder()
//! // global max log level
//! .max_log_level(LevelFilter::Info)
//! // custom timestamp format
//! .time_format(time_format)
//! // set global log formatter
//! .format(FtLogFormatter)
//! // use bounded channel to avoid large memory comsumption when overwhelmed with logs
//! // Set `false` to tell ftlog to discard excessive logs.
//! // Set `true` to block log call to wait for log thread.
//! // here is the default settings
//! .bounded(100_000, false) // .unbounded()
//! // define root appender, pass anything that is Write and Send
//! // omit `Builder::root` will write to stderr
//! .root(FileAppender::rotate_with_expire(
//! "./current.log",
//! Period::Day,
//! Duration::days(7),
//! ))
//! // Do not convert to local timezone for timestamp, this does not affect worker thread,
//! // but can boost log thread performance (higher throughput).
//! .utc()
//! // level filter for root appender
//! .root_log_level(LevelFilter::Warn)
//! // write logs in ftlog::appender to "./ftlog-appender.log" instead of "./current.log"
//! .filter("ftlog::appender", "ftlog-appender", LevelFilter::Error)
//! .appender("ftlog-appender", FileAppender::new("ftlog-appender.log"))
//! .try_init()
//! .expect("logger build or set failed");
//! ```
//!
//! See `./examples` for more (e.g. custom format).
//!
//! ## Default Log Format
//!
//! > 2022-04-08 19:20:48.190+08 **298ms** INFO main [src/ftlog.rs:14] My log
//! > message
//!
//! Here `298ms` denotes the latency between the call of the log (e.g.
//! `log::info!("msg")`) and the actual printing in log thread. Normally this is 0ms.
//!
//! A large delay indicates that the log thread may be blocked by excessive log
//! messages.
//!
//! > 2022-04-10 21:27:15.996+08 0ms **2** INFO main [src/main.rs:29] limit
//! > running3 !
//!
//! The number **2** above indicates how many log messages were discarded.
//! Only shown if the frequency of logging for a single log call is limited (e.g.
//! `log::info!(limit=3000i64;"msg")`).
//!
//! ## Randomly drop log
//!
//! Use `random_drop` to specify the probability of randomly discarding logs.
//! No message is dropped by default.
//!
//! ```rust
//! log::info!(random_drop=0.1f64;"Random log 10% of log calls");
//! ```
//!
//! This can be helpful when formatting log message into string is too costly,
//!
//! When both `random_drop` and `limit` is specified,
//! ftlog will limit logs after messages are randomly dropped.
//!
//! ## Custom timestamp format
//!
//! `ftlog` relies on the `time` crate for the formatting of timestamp. To use custom time format,
//! first construct a valid time format description,
//! and then pass it to ftlog builder by `ftlog::time_format(&mut self)`.
//!
//! In case an error occurs when formatting timestamp, `ftlog` will fallback to RFC3339 time format.
//!
//! ### Example
//! ```rust
//! let format = time::format_description::parse_owned::<1>(
//! "[year]/[month]/[day] [hour]:[minute]:[second].[subsecond digits:6]",
//! )
//! .unwrap();
//! ftlog::builder().time_format(format).try_init().unwrap();
//! log::info!("Log with custom timestamp format");
//! // Output:
//! // 2023/06/14 11:13:26.160840 0ms INFO main [main.rs:3] Log with custom timestamp format
//! ```
//!
//! ## Log with interval
//!
//! `ftlog` allows to limit the write frequency for individual log calls.
//!
//! If the above line is called multiple times within 3000ms, then it is logged only
//! once, with an added number reflecting the number of discarded log messages.
//!
//! Each log call ha an independent interval, so we can set different intervals
//! for different log calls. Internally, `ftlog` records the last print time by a
//! combination of (module name, file name, code line).
//!
//! ### Example
//!
//! ```rust
//! # use ftlog::info;
//! info!(limit=3000i64; "limit running {}s !", 3);
//! ```
//! The minimal interval of the the specific log call above is 3000ms.
//!
//! ```markdown
//! 2022-04-10 21:27:10.996+08 0ms 0 INFO main [src/main.rs:29] limit running 3s !
//! 2022-04-10 21:27:15.996+08 0ms 2 INFO main [src/main.rs:29] limit running 3s !
//! ```
//! The number **2** above shows how many log messages is discarded since last log.
//!
//! ## Log rotation
//! `ftlog` supports log rotation in local timezone. The available rotation
//! periods are:
//!
//! - minute `Period::Minute`
//! - hour `Period::Hour`
//! - day `Period::Day`
//! - month `Period::Month`
//! - year `Period::Year`
//!
//! Log rotation is configured in `FileAppender`, and the timestamp is appended to
//! the end of the filename:
//!
//! ```rust
//! use ftlog::appender::{FileAppender, Period};
//!
//! let logger = ftlog::builder()
//! .root(FileAppender::rotate("./mylog.log", Period::Minute))
//! .build()
//! .unwrap();
//! logger.init().unwrap();
//! ```
//!
//! If the log file is configued to be split by minutes,
//! the log file name has the format
//! `mylog-{MMMM}{YY}{DD}T{hh}{mm}.log`. When divided by days, the log file name is
//! something like `mylog-{MMMM}{YY}{DD}.log`.
//!
//! Log filename examples:
//! ```sh
//! $ ls
//! # by minute
//! current-20221026T1351.log
//! # by hour
//! current-20221026T13.log
//! # by day
//! current-20221026.log
//! # by month
//! current-202210.log
//! # by year
//! current-2022.log
//! # omitting extension (e.g. "./log") will add datetime to the end of log filename
//! log-20221026T1351
//! ```
//!
//! ### Clean outdated logs
//!
//! With log rotation enabled, it is possible to clean outdated logs to free up
//! disk space with `FileAppender::rotate_with_expire` method.
//!
//! `ftlog` first finds files generated by `ftlog` and cleans outdated logs by
//! last modified time. `ftlog` find generated logs by filename matched by file
//! stem and added datetime.
//!
//! **ATTENTION**: Any files that matchs the pattern will be deleted.
//!
//! ```rust
//! use ftlog::{appender::{Period, FileAppender, Duration}};
//!
//! // clean files named like `current-\d{8}T\d{4}.log`.
//! // files like `another-\d{8}T\d{4}.log` or `current-\d{8}T\d{4}` will not be deleted, since the filenames' stem do not match.
//! // files like `current-\d{8}.log` will remains either, since the rotation durations do not match.
//!
//! // Rotate every day, clean stale logs that were modified 7 days ago on each rotation
//! let appender = FileAppender::rotate_with_expire("./current.log", Period::Day, Duration::days(7));
//! let logger = ftlog::builder()
//! .root(appender)
//! .build()
//! .unwrap();
//! logger.init().unwrap();
//! ```
//!
//! # Features
//! - **tsc**
//! Use [TSC](https://en.wikipedia.org/wiki/Time_Stamp_Counter) for clock source for higher performance without
//! accuracy loss.
//!
//! TSC offers the most accurate and cheapest way to access current time under certain condition:
//! 1. the CPU frequency must be constant
//! 1. must with CPU of x86/x86_64 architecture, since TSC is an x86/x86_64 specific register.
//! 1. never suspend
//!
//! The current feature further requires that the build target **MUST BE LINUX**. Otherwise it will fall back to
//! a fast but much less accurate implementation.
//!
//! # Timezone
//!
//! For performance, timezone is detected once at logger buildup, and use it later in every
//! log message. This is partly due to timezone detetion is expensive, and partly to the unsafe
//! nature of underlying system call in multi-thread program in Linux.
//!
//! It's also recommended to use UTC instead to further avoid timestamp convertion to timezone for every log message.
//!
//! # Performance
//!
//! > Rust：1.67.0-nightly
//!
//! | | message type | Apple M1 Pro, 3.2GHz | AMD EPYC 7T83, 3.2GHz |
//! | ------------------------------------------------- | ------------- | --------------------- | --------------------- |
//! | `ftlog` | static string | 75 ns/iter | 385 ns/iter |
//! | `ftlog` | with i32 | 106 ns/iter | 491 ns/iter |
//! | `env_logger` <br/> output to file | static string | 1,674 ns/iter | 1,142 ns/iter |
//! | `env_logger` <br/> output to file | with i32 | 1,681 ns/iter | 1,179 ns/iter |
//! | `env_logger` <br/> output to file with `BufWriter`| static string | 279 ns/iter | 550 ns/iter |
//! | `env_logger` <br/> output to file with `BufWriter`| with i32 | 278 ns/iter | 565 ns/iter |
use arc_swap::ArcSwap;
pub use log::{
debug, error, info, log, log_enabled, logger, trace, warn, Level, LevelFilter, Record,
};
use time::format_description::OwnedFormatItem;
use time::{OffsetDateTime, UtcOffset};
use std::borrow::Cow;
use std::fmt::Display;
use std::hash::{BuildHasher, Hash, Hasher};
use std::io::{stderr, Error as IoError, Write};
use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
use std::sync::Arc;
use std::time::{Duration, Instant};
use crossbeam_channel::{bounded, unbounded, Receiver, RecvTimeoutError, Sender, TrySendError};
use hashbrown::HashMap;
use log::{kv::Key, set_boxed_logger, set_max_level, Log, Metadata, SetLoggerError};
pub mod appender;
use tm::{duration, now, to_utc, Time};
#[cfg(not(feature = "tsc"))]
mod tm {
use super::*;
pub type Time = std::time::SystemTime;
#[inline]
pub fn now() -> Time {
std::time::SystemTime::now()
}
#[inline]
pub fn to_utc(time: Time) -> OffsetDateTime {
time.into()
}
#[inline]
pub fn duration(from: Time, to: Time) -> Duration {
to.duration_since(from).unwrap_or_default()
}
}
#[cfg(feature = "tsc")]
mod tm {
use super::*;
pub type Time = minstant::Instant;
#[inline]
pub fn now() -> Time {
minstant::Instant::now()
}
#[inline]
pub fn to_utc(time: Time) -> OffsetDateTime {
static ANCHOR: once_cell::sync::Lazy<minstant::Anchor> =
once_cell::sync::Lazy::new(|| minstant::Anchor::new());
OffsetDateTime::from_unix_timestamp_nanos(time.as_unix_nanos(&ANCHOR) as i128).unwrap()
}
#[inline]
pub fn duration(from: Time, to: Time) -> Duration {
to.duration_since(from)
}
}
#[cfg(target_family = "unix")]
fn local_timezone() -> UtcOffset {
UtcOffset::current_local_offset().unwrap_or_else(|_| {
let tz = tz::TimeZone::local().unwrap();
let current_local_time_type = tz.find_current_local_time_type().unwrap();
let diff_secs = current_local_time_type.ut_offset();
UtcOffset::from_whole_seconds(diff_secs).unwrap()
})
}
#[cfg(not(target_family = "unix"))]
fn local_timezone() -> UtcOffset {
UtcOffset::current_local_offset().unwrap_or(UtcOffset::UTC)
}
struct LogMsg {
time: Time,
msg: Box<dyn Sync + Send + Display>,
level: Level,
target: String,
limit: u32,
limit_key: u64,
}
impl LogMsg {
fn write(
self,
filters: &Vec<Directive>,
appenders: &mut HashMap<&'static str, Box<dyn Write + Send>>,
root: &mut Box<dyn Write + Send>,
root_level: LevelFilter,
missed_log: &mut HashMap<u64, i64, nohash_hasher::BuildNoHashHasher<u64>>,
last_log: &mut HashMap<u64, Time, nohash_hasher::BuildNoHashHasher<u64>>,
offset: Option<UtcOffset>,
time_format: &time::format_description::OwnedFormatItem,
) {
let now = now();
let writer = if let Some(filter) = filters.iter().find(|x| self.target.starts_with(x.path))
{
if filter.level.map(|l| l < self.level).unwrap_or(false) {
return;
}
filter
.appender
.and_then(|n| appenders.get_mut(n))
.unwrap_or(root)
} else {
if root_level < self.level {
return;
}
root
};
if self.limit > 0 {
let missed_entry = missed_log.entry(self.limit_key).or_insert_with(|| 0);
if let Some(last) = last_log.get(&self.limit_key) {
if duration(*last, now) < Duration::from_millis(self.limit as u64) {
*missed_entry += 1;
return;
}
}
last_log.insert(self.limit_key, now);
let delay = duration(self.time, now);
let utc_datetime = to_utc(self.time);
let offset_datetime = offset
.map(|o| utc_datetime.to_offset(o))
.unwrap_or(utc_datetime);
let s = format!(
"{} {}ms {} {}\n",
offset_datetime
.format(&time_format)
.unwrap_or_else(|_| offset_datetime
.format(&time::format_description::well_known::Rfc3339)
.unwrap()),
delay.as_millis(),
*missed_entry,
self.msg
);
if let Err(e) = writer.write_all(s.as_bytes()) {
eprintln!("logger write message failed: {}", e);
};
*missed_entry = 0;
} else {
let delay = duration(self.time, now);
let utc_datetime = to_utc(self.time);
let offset_datetime = offset
.map(|o| utc_datetime.to_offset(o))
.unwrap_or(utc_datetime);
let s = format!(
"{} {}ms {}\n",
offset_datetime
.format(&time_format)
.unwrap_or_else(|_| offset_datetime
.format(&time::format_description::well_known::Rfc3339)
.unwrap()),
delay.as_millis(),
self.msg
);
if let Err(e) = writer.write_all(s.as_bytes()) {
eprintln!("logger write message failed: {}", e);
};
}
}
}
enum LoggerInput {
LogMsg(LogMsg),
Flush,
}
#[derive(Debug)]
enum LoggerOutput {
Flushed,
FlushError(std::io::Error),
}
/// Shared by ftlog formatter
///
/// To further reduce time spent on log macro calls, ftlog saves required data
/// and later construct log string in log thread.
///
/// `FtLogFormat` defines how to turn an reference to record into a box object,
/// which can be sent to log thread and later formatted into string.
///
/// Here is an example of custom formatter:
///
/// ```
/// use std::fmt::Display;
///
/// use ftlog::FtLogFormat;
/// use log::{Level, Record};
///
/// struct MyFormatter;
/// impl FtLogFormat for MyFormatter {
/// fn msg(&self, record: &Record) -> Box<dyn Send + Sync + Display> {
/// Box::new(Msg {
/// level: record.level(),
/// thread: std::thread::current().name().map(|n| n.to_string()),
/// file: record.file_static(),
/// line: record.line(),
/// args: format!("{}", record.args()),
/// module_path: record.module_path_static(),
/// })
/// }
/// }
/// // Store necessary field, define how to format into string with `Display` trait.
/// struct Msg {
/// level: Level,
/// thread: Option<String>,
/// file: Option<&'static str>,
/// line: Option<u32>,
/// args: String,
/// module_path: Option<&'static str>,
/// }
///
/// impl Display for Msg {
/// fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
/// f.write_str(&format!(
/// "{}@{}||{}:{}[{}] {}",
/// self.thread.as_ref().map(|x| x.as_str()).unwrap_or(""),
/// self.module_path.unwrap_or(""),
/// self.file.unwrap_or(""),
/// self.line.unwrap_or(0),
/// self.level,
/// self.args
/// ))
/// }
/// }
/// ```
pub trait FtLogFormat: Send + Sync {
/// turn an reference to record into a box object, which can be sent to log thread
/// and then formatted into string.
fn msg(&self, record: &Record) -> Box<dyn Send + Sync + Display>;
}
/// Default ftlog formatter
///
/// The default ftlog format is like:
/// ```text
/// INFO main [examples/ftlog.rs:27] Hello, world!
/// ```
///
/// Since ftlog cannot customize timestamp, the corresponding part is omitted.
/// The actual log output is like:
/// ```text
/// 2022-11-22 17:02:12.574+08 0ms INFO main [examples/ftlog.rs:27] Hello, world!
/// ```
pub struct FtLogFormatter;
impl FtLogFormat for FtLogFormatter {
/// Return a box object that contains required data (e.g. thread name, line of code, etc.) for later formatting into string
#[inline]
fn msg(&self, record: &Record) -> Box<dyn Send + Sync + Display> {
Box::new(Message {
level: record.level(),
thread: std::thread::current().name().map(|n| n.to_string()),
file: record
.file_static()
.map(|s| Cow::Borrowed(s))
.or_else(|| record.file().map(|s| Cow::Owned(s.to_owned())))
.unwrap_or(Cow::Borrowed("")),
line: record.line(),
args: record
.args()
.as_str()
.map(|s| Cow::Borrowed(s))
.unwrap_or_else(|| Cow::Owned(format!("{}", record.args()))),
})
}
}
struct Message {
level: Level,
thread: Option<String>,
file: Cow<'static, str>,
line: Option<u32>,
args: Cow<'static, str>,
}
impl Display for Message {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_str(&format!(
"{} {} [{}:{}] {}",
self.level,
self.thread.as_ref().map(|x| x.as_str()).unwrap_or(""),
self.file,
self.line.unwrap_or(0),
self.args
))
}
}
struct DiscardState {
last: ArcSwap<Instant>,
count: AtomicUsize,
}
/// ftlog global logger
pub struct Logger {
format: Box<dyn FtLogFormat>,
level: LevelFilter,
queue: Sender<LoggerInput>,
notification: Receiver<LoggerOutput>,
block: bool,
discard_state: Option<DiscardState>,
stopped: AtomicBool,
}
impl Logger {
pub fn init(self) -> Result<(), SetLoggerError> {
set_max_level(self.level);
let boxed = Box::new(self);
set_boxed_logger(boxed)
}
}
impl Log for Logger {
#[inline]
fn enabled(&self, metadata: &Metadata) -> bool {
// already checked in log macros
self.level >= metadata.level()
}
fn log(&self, record: &Record) {
let random_drop = record
.key_values()
.get(Key::from_str("random_drop"))
.and_then(|x| x.to_f64())
.unwrap_or(1.) as f32;
if random_drop < 1. && fastrand::f32() < random_drop {
return;
}
let limit = record
.key_values()
.get(Key::from_str("limit"))
.and_then(|x| x.to_u64())
.unwrap_or(0) as u32;
let msg = self.format.msg(record);
let limit_key = if limit == 0 {
0
} else {
let mut b = hashbrown::hash_map::DefaultHashBuilder::default().build_hasher();
if let Some(p) = record.module_path() {
p.as_bytes().hash(&mut b);
} else {
record.file().unwrap_or("").as_bytes().hash(&mut b);
}
record.line().unwrap_or(0).hash(&mut b);
b.finish()
};
let msg = LoggerInput::LogMsg(LogMsg {
time: now(),
msg: msg,
target: record.target().to_owned(),
level: record.level(),
limit,
limit_key,
});
if self.block {
if let Err(_) = self.queue.send(msg) {
let stop = self.stopped.load(Ordering::SeqCst);
if !stop {
eprintln!("logger queue closed when logging, this is a bug");
self.stopped.store(true, Ordering::SeqCst)
}
}
} else {
match self.queue.try_send(msg) {
Err(TrySendError::Full(_)) => {
if let Some(s) = &self.discard_state {
let count = s.count.fetch_add(1, Ordering::SeqCst);
if s.last.load().elapsed().as_secs() >= 5 {
eprintln!("Excessive log messages. Log omitted: {}", count);
s.last.store(Arc::new(Instant::now()));
}
}
}
Err(TrySendError::Disconnected(_)) => {
let stop = self.stopped.load(Ordering::SeqCst);
if !stop {
eprintln!("logger queue closed when logging, this is a bug");
self.stopped.store(true, Ordering::SeqCst)
}
}
_ => (),
}
}
}
fn flush(&self) {
self.queue
.send(LoggerInput::Flush)
.expect("logger queue closed when flushing, this is a bug");
self.notification
.recv()
.expect("logger notification closed, this is a bug");
}
}
struct BoundedChannelOption {
size: usize,
block: bool,
print: bool,
}
/// Ftlog builder
///
/// ```
/// # use ftlog::appender::{FileAppender, Duration, Period};
/// # use log::LevelFilter;
/// let logger = ftlog::builder()
/// // use our own format
/// .format(ftlog::FtLogFormatter)
/// // global max log level
/// .max_log_level(LevelFilter::Info)
/// // define root appender, pass anything that is Write and Send
/// // omit `Builder::root` to write to stderr
/// .root(FileAppender::rotate_with_expire(
/// "./current.log",
/// Period::Day,
/// Duration::days(7),
/// ))
/// // ---------- configure additional filter ----------
/// // write to "ftlog-appender" appender, with different level filter
/// .filter("ftlog::appender", "ftlog-appender", LevelFilter::Error)
/// // write to root appender, but with different level filter
/// .filter("ftlog", None, LevelFilter::Trace)
/// // write to "ftlog" appender, with default level filter
/// .filter("ftlog::appender::file", "ftlog", None)
/// // ---------- configure additional appender ----------
/// // new appender
/// .appender("ftlog-appender", FileAppender::new("ftlog-appender.log"))
/// // new appender, rotate to new file every Day
/// .appender("ftlog", FileAppender::rotate("ftlog.log", Period::Day))
/// .build()
/// .expect("logger build failed");
/// ```
///
/// # Local timezone
/// For performance reason, `ftlog` only retrieve timezone info once and use this
/// local timezone offset forever. Thus timestamp in log does not aware of timezone
/// change by OS.
///
pub struct Builder {
format: Box<dyn FtLogFormat>,
time_format: Option<OwnedFormatItem>,
level: Option<LevelFilter>,
root_level: Option<LevelFilter>,
root: Box<dyn Write + Send>,
appenders: HashMap<&'static str, Box<dyn Write + Send + 'static>>,
filters: Vec<Directive>,
bounded_channel_option: Option<BoundedChannelOption>,
local_timezone: bool,
}
/// Handy function to get ftlog builder
#[inline]
pub fn builder() -> Builder {
Builder::new()
}
struct Directive {
path: &'static str,
level: Option<LevelFilter>,
appender: Option<&'static str>,
}
impl Builder {
#[inline]
/// Create a ftlog builder with default settings:
/// - global log level: INFO
/// - root log level: INFO
/// - default formatter: `FtLogFormatter`
/// - output to stderr
/// - bounded channel between worker thread and log thread, with a size limit of 100_000
/// - discard excessive log messages
/// - log with timestamp of local timezone
pub fn new() -> Builder {
Builder {
format: Box::new(FtLogFormatter),
level: None,
root_level: None,
root: Box::new(stderr()) as Box<dyn Write + Send>,
appenders: HashMap::new(),
filters: Vec::new(),
bounded_channel_option: Some(BoundedChannelOption {
size: 100_000,
block: false,
print: false,
}),
local_timezone: true,
time_format: None,
}
}
/// Set custom formatter
#[inline]
pub fn format<F: FtLogFormat + 'static>(mut self, format: F) -> Builder {
self.format = Box::new(format);
self
}
/// Set custom datetime formatter
#[inline]
pub fn time_format(mut self, format: OwnedFormatItem) -> Builder {
self.time_format = Some(format);
self
}
/// bound channel between worker thread and log thread
///
/// When `block_when_full` is true, it will block current thread where
/// log macro (e.g. `log::info`) is called until log thread is able to handle new message.
/// Otherwises, excessive log messages will be discarded.
///
/// By default, excessive log messages is discarded silently. To show how many log
/// messages have been dropped, see `Builder::print_omitted_count()`.
#[inline]
pub fn bounded(mut self, size: usize, block_when_full: bool) -> Builder {
self.bounded_channel_option = Some(BoundedChannelOption {
size,
block: block_when_full,
print: false,
});
self
}
/// whether to print the number of omitted logs if channel to log
/// thread is bounded, and set to discard excessive log messages
#[inline]
pub fn print_omitted_count(mut self, print: bool) -> Builder {
self.bounded_channel_option
.as_mut()
.map(|o| o.print = print);
self
}
/// set channel size to unbound
///
/// **ATTENTION**: too much log message will lead to huge memory consumption,
/// as log messages are queued to be handled by log thread.
/// When log message exceed the current channel size, it will double the size by default,
/// Since channel expansion asks for memory allocation, log calls can be slow down.
#[inline]
pub fn unbounded(mut self) -> Builder {
self.bounded_channel_option = None;
self
}
/// Add an additional appender with a name
///
/// Combine with `Builder::filter()`, ftlog can output log in different module
/// path to different output target.
#[inline]
pub fn appender(
mut self,
name: &'static str,
appender: impl Write + Send + 'static,
) -> Builder {
self.appenders.insert(name, Box::new(appender));
self
}
/// Add a filter to redirect log to different output
/// target (e.g. stderr, stdout, different files).
///
/// **ATTENTION**: level more verbose than `Builder::max_log_level` will be ignored.
/// Say we configure `max_log_level` to INFO, and even if filter's level is set to DEBUG,
/// ftlog will still log up to INFO.
#[inline]
pub fn filter<A: Into<Option<&'static str>>, L: Into<Option<LevelFilter>>>(
mut self,
module_path: &'static str,
appender: A,
level: L,
) -> Builder {
let appender = appender.into();
let level = level.into();
if appender.is_some() || level.is_some() {
self.filters.push(Directive {
path: module_path,
appender: appender,
level: level,
});
}
self
}
#[inline]
/// Configure the default log output target.
///
/// Omit this method will output to stderr.
pub fn root(mut self, writer: impl Write + Send + 'static) -> Builder {
self.root = Box::new(writer);
self
}
#[inline]
/// Set max log level
///
/// Logs with level more verbose than this will not be sent to log thread.
pub fn max_log_level(mut self, level: LevelFilter) -> Builder {
self.level = Some(level);
self
}
#[inline]
/// Set max log level
///
/// Logs with level more verbose than this will not be sent to log thread.
pub fn root_log_level(mut self, level: LevelFilter) -> Builder {
self.root_level = Some(level);
self
}
#[inline]
/// Log with timestamp of local timezone
///
/// Timezone is fixed after logger setup for the following reasons:
/// 1. `time` v0.3 currently do not allow access to local offset for multithread process
/// in unix-like OS.
/// 1. timezone retrieval from OS is quite slow (around several microsecond) compare with
/// utc timestamp retrieval (around tens of nanoseconds)
pub fn local_timezone(mut self) -> Builder {
self.local_timezone = true;
self
}
#[inline]
/// Log with timestamp of UTC timezone
pub fn utc(mut self) -> Builder {
self.local_timezone = false;
self
}
/// Finish building ftlog logger
///
/// The call spawns a log thread to formatting log message into string,
/// and write to output target.
pub fn build(self) -> Result<Logger, IoError> {
let offset = self.local_timezone.then(|| local_timezone());
let time_format = self.time_format.unwrap_or_else(|| {
time::format_description::parse_owned::<1>(
"[year]-[month]-[day] [hour]:[minute]:[second].[subsecond digits:3]+[offset_hour]",
)
.unwrap()
});
let mut filters = self.filters;
// sort filters' paths to ensure match for longest path
filters.sort_by(|a, b| a.path.len().cmp(&b.path.len()));
filters.reverse();
// check appender name in filters are all valid
for appender_name in filters.iter().filter_map(|x| x.appender) {
if !self.appenders.contains_key(appender_name) {
panic!("Appender {} not configured", appender_name);
}
}
let global_level = self.level.unwrap_or(LevelFilter::Info);
let root_level = self.root_level.unwrap_or(global_level);
if global_level < root_level {
warn!(
"Logs with level more verbose than {} will be ignored",
global_level,
);
}
let (sync_sender, receiver) = match &self.bounded_channel_option {
None => unbounded(),
Some(option) => bounded(option.size),
};
let (notification_sender, notification_receiver) = bounded(1);
std::thread::Builder::new()
.name("logger".to_string())
.spawn(move || {
let mut appenders = self.appenders;
let filters = filters;
for filter in &filters {
if let Some(level) = filter.level {
if global_level < level {
warn!(
"Logs with level more verbose than {} will be ignored in `{}` ",
global_level, filter.path,
);
}
}
}
let mut root = self.root;
let mut last_log = HashMap::default();
let mut missed_log = HashMap::default();
let mut last_flush = Instant::now();
let timeout = Duration::from_millis(200);
loop {
match receiver.recv_timeout(timeout) {
Ok(LoggerInput::LogMsg(log_msg)) => {
log_msg.write(
&filters,
&mut appenders,
&mut root,
root_level,
&mut missed_log,
&mut last_log,
offset,
&time_format,
);
}
Ok(LoggerInput::Flush) => {
let max = receiver.len();
'queue: for _ in 1..=max {
if let Ok(LoggerInput::LogMsg(msg)) = receiver.try_recv() {
msg.write(
&filters,
&mut appenders,
&mut root,
root_level,
&mut missed_log,
&mut last_log,
offset,
&time_format,
)
} else {
break 'queue;
}
}
let flush_result = appenders
.values_mut()
.chain([&mut root])
.find_map(|w| w.flush().err());
if let Some(error) = flush_result {
notification_sender
.send(LoggerOutput::FlushError(error))
.expect("logger notification failed");
} else {
notification_sender
.send(LoggerOutput::Flushed)
.expect("logger notification failed");
}
}
Err(RecvTimeoutError::Timeout) => {
if last_flush.elapsed() > Duration::from_millis(1000) {
let flush_errors = appenders
.values_mut()
.chain([&mut root])
.filter_map(|w| w.flush().err());
for err in flush_errors {
log::warn!("Ftlog flush error: {}", err);
}
last_flush = Instant::now();
};
}
Err(e) => {
eprintln!(
"sender closed without sending a Quit first, this is a bug, {}",
e
);
}
}
}
})?;
let block = self
.bounded_channel_option
.as_ref()
.map(|x| x.block)
.unwrap_or(false);
let print = self
.bounded_channel_option
.as_ref()
.map(|x| x.print)
.unwrap_or(false);
Ok(Logger {
format: self.format,
level: global_level,
queue: sync_sender,
notification: notification_receiver,
block,
discard_state: if block || !print {
None
} else {
Some(DiscardState {
last: ArcSwap::new(Arc::new(Instant::now())),
count: AtomicUsize::new(0),
})
},
stopped: AtomicBool::new(false),
})
}
/// try building and setting as global logger
pub fn try_init(self) -> Result<(), Box<dyn std::error::Error>> {
let logger = self.build()?;
Ok(logger.init()?)
}
}
impl Default for Builder {
#[inline]
fn default() -> Self {
Builder::new()
}
}