1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380
// Copyright 2015 Axel Rasmussen
//
// 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.
/// write provides adapters to use anything which implements Write as a logging
/// destination.
pub mod write;
use crate::error::*;
use crate::logging::write::*;
use chrono;
use lazy_static::lazy_static;
use log::{self, LevelFilter, Log, Metadata, Record};
use regex::Regex;
use std::collections::HashMap;
use std::io::Write;
use std::str::FromStr;
const RUST_LOG_ENV_VAR: &'static str = "RUST_LOG";
/// This is a utility function which provides a way to parse a log::LevelFilter
/// from a string. Upstream doesn't impl FromStr for this type, so this extra
/// utility is necessary.
pub fn parse_log_level_filter(s: &str) -> Result<LevelFilter> {
lazy_static! {
static ref STRING_MAPPING: HashMap<String, LevelFilter> = {
let mut m = HashMap::new();
m.insert(
LevelFilter::Off.to_string().to_lowercase(),
LevelFilter::Off,
);
m.insert(
LevelFilter::Error.to_string().to_lowercase(),
LevelFilter::Error,
);
m.insert(
LevelFilter::Warn.to_string().to_lowercase(),
LevelFilter::Warn,
);
m.insert(
LevelFilter::Info.to_string().to_lowercase(),
LevelFilter::Info,
);
m.insert(
LevelFilter::Debug.to_string().to_lowercase(),
LevelFilter::Debug,
);
m.insert(
LevelFilter::Trace.to_string().to_lowercase(),
LevelFilter::Trace,
);
m
};
}
let normalized = s.trim().to_lowercase();
match STRING_MAPPING.get(&normalized) {
None => {
return Err(Error::InvalidArgument(format!(
"invalid LevelFilter '{}'",
s
)));
}
Some(f) => Ok(*f),
}
}
/// A LogFilter is a single filter, perhaps one of many, that can be applied to
/// log messages before actually outputting them.
pub struct LogFilter {
/// This LogFilter is intended to be applied to any modules which match this
/// regular expression. If this field is None instead, then this LogFilter
/// should be applied to *all* modules.
pub module: Option<Regex>,
/// The LevelFilter which should be applied to matching modules.
pub level: LevelFilter,
}
impl LogFilter {
/// The LevelFilter this LogFilter applies to the given module. If this
/// LogFilter does not match the given module, then None is returned
/// instead.
pub fn max_level_for(&self, module_path: &str) -> Option<LevelFilter> {
match self.module {
None => Some(self.level),
Some(ref module) => match module.is_match(module_path) {
false => None,
true => Some(self.level),
},
}
}
}
impl FromStr for LogFilter {
type Err = Error;
fn from_str(s: &str) -> Result<LogFilter> {
match s.rfind('=') {
None => Ok(LogFilter {
module: None,
level: parse_log_level_filter(s)?,
}),
Some(eq_pos) => {
let mut re: String = "^".to_owned();
re.push_str(&s[..eq_pos]);
Ok(LogFilter {
module: Some(Regex::new(&re)?),
level: parse_log_level_filter(&s[eq_pos + 1..])?,
})
}
}
}
}
/// LogFilters is a structure which defines the full set of filters a Logger
/// should apply to log messages before actually outputting them.
pub struct LogFilters(pub Vec<LogFilter>);
impl LogFilters {
/// Returns the LevelFilter which should be applied to the given module. If
/// no LogFilter entries apply to the given module, Trace is returned
/// instead, since logging messages are enabled by default in this library.
/// If multiple LevelFilters matched the given module, then the *lowest*
/// (i.e., most restrictive) LevelFilter is returned.
pub fn max_level_for(&self, module_path: &str) -> LevelFilter {
self.0
.iter()
.filter_map(|f| f.max_level_for(module_path))
.min()
.unwrap_or(LevelFilter::Trace)
}
}
impl FromStr for LogFilters {
type Err = Error;
/// Parse a set of log filters from a string.
///
/// We assume that the regex contained in log filters will only contain
/// certain characters: those which can appear in valid module names
/// (something like [A-Za-z_][A-Za-z0-9_]* separated by :'s), and maybe
/// some modifiers or etc., like *+?|(){}[].
///
/// But, we want a string to contain *several* filters. So, using the
/// above assumption about what characters will appear in the regex,
/// we'll use the ; character as a separator. So, the final format is:
///
/// regex=level;regex=level;...
fn from_str(s: &str) -> Result<LogFilters> {
let filters: Result<Vec<LogFilter>> = s.split(';').map(|f| f.parse()).collect();
Ok(LogFilters(filters?))
}
}
/// Options is a structure which describes the options for a Logger. Generally
/// these should be constructed using OptionsBuilder, instead of filling in all
/// fields by hand.
pub struct Options {
/// Filters controlling which log statements are enabled. If unspecified,
/// defaults to the value of the RUST_LOG environment variable. If that is
/// also unspecified, then by default all logging statements are enabled.
pub filters: LogFilters,
/// The global maximum enabled logging level. This is basically the highest
/// level configured in any of `filters`, or `LevelFilter::Trace` by default
/// (meaning that all log messages are enabled, if no filters are
/// specified).
pub max_level: LevelFilter,
/// Where to write log output to. If unspecified, defaults to stderr.
pub output_factory: LogOutputFactory,
/// Whether or not a log output (or flush) failure should result in a panic.
/// Panicing is the "safest" option in some sense, but the default behavior
/// is to silently ignore failures (under the assumption that most of the
/// time users will want the application to continue working even if it
/// can't produce log output).
pub panic_on_output_failure: bool,
/// If true, *always* call flush() after each log statement. This has a
/// significant negative impact on performance, but it does mean that log
/// statements will appear immediately, which may be useful e.g. for
/// debugging. By default, this feature is disabled.
pub always_flush: bool,
}
/// OptionsBuilder provides a builder-style interface to construct an Options.
pub struct OptionsBuilder {
filters: Option<LogFilters>,
output_factory: Option<LogOutputFactory>,
panic_on_output_failure: Option<bool>,
always_flush: Option<bool>,
}
impl OptionsBuilder {
/// Construct a new OptionsBuilder, which by default just sets the options
/// to their default values.
pub fn new() -> Self {
OptionsBuilder {
filters: None,
output_factory: None,
panic_on_output_failure: None,
always_flush: None,
}
}
/// Set the filters which will be applied to any logging calls before
/// actually logging them.
pub fn set_filters(mut self, filters: LogFilters) -> Self {
self.filters = Some(filters);
self
}
/// Set the output factory the Logger should use. This can be used to
/// redirect logging output more generically, although for the common case
/// set_output_to might be easier to use.
pub fn set_output_factory(mut self, output_factory: LogOutputFactory) -> Self {
self.output_factory = Some(output_factory);
self
}
/// Configure the Logger to write its log output to the given Write
/// implementation (e.g. a File). This is a convenience function which
/// just calls set_output_factory under the hood.
pub fn set_output_to<T: Write + Send + 'static>(self, output_writer: T) -> Self {
self.set_output_factory(new_log_output_factory(output_writer))
}
/// Set whether or not the Logger should panic! if writing log output fails.
/// Generally this can be useful for debugging, but in real production code
/// losing a log entry might not be a good enough reason to terminate the
/// entire process.
pub fn set_panic_on_output_failure(mut self, panic_on_output_failure: bool) -> Self {
self.panic_on_output_failure = Some(panic_on_output_failure);
self
}
/// Set whether or not the Logger should flush its output after every
/// logging call. The benefit is that log messages show up immediately, and
/// are less susceptible to "corruption" when logging from multiple threads,
/// but the cost is a significant performance penalty for all logging calls.
pub fn set_always_flush(mut self, always_flush: bool) -> Self {
self.always_flush = Some(always_flush);
self
}
/// Build an Options structure from this builder's current state. This might
/// return an error if no custom filters were specified, and attempting to
/// retrieve filters from an environment variable fails.
pub fn build(self) -> Result<Options> {
let filters: LogFilters = match self.filters {
None => match get_env_var(RUST_LOG_ENV_VAR)? {
None => LogFilters(vec![]),
Some(filters_str) => filters_str.parse()?,
},
Some(filters) => filters,
};
let max_level: LevelFilter = filters
.0
.iter()
.map(|f| f.level)
.max()
.unwrap_or(LevelFilter::Trace);
Ok(Options {
filters: filters,
max_level: max_level,
output_factory: self
.output_factory
.unwrap_or_else(|| Box::new(|| Box::new(::std::io::stderr()))),
panic_on_output_failure: self.panic_on_output_failure.unwrap_or(false),
always_flush: self.always_flush.unwrap_or(false),
})
}
}
fn get_env_var(key: &str) -> Result<Option<String>> {
match ::std::env::var(key) {
Ok(v) => Ok(Some(v)),
Err(e) => match e {
::std::env::VarError::NotPresent => Ok(None),
_ => Err(Error::EnvVar(e)),
},
}
}
/// This function formats the given log Record into a string, which can then be
/// written directly to the logging sink (e.g. stderr, a file, etc.).
pub fn format_log_record(record: &Record) -> String {
format!(
"[{} {}:{}] {} - {}",
chrono::Utc::now().format("%Y-%m-%d %H:%M:%S UTC"),
record.file().unwrap_or("UNKNOWN_FILE"),
record
.line()
.map_or("UNKNOWN_LINE".to_owned(), |l| l.to_string()),
record.level(),
record.args()
)
}
/// This is the standard Log implementation bdrck provides, which can be
/// controlled by setting its Options. In general, this is intended to be a
/// pretty versatile implementation, suitable for both command-line applications
/// as well as serving daemons, given the right Options.
pub struct Logger {
options: Options,
}
impl Logger {
/// Construct a new Logger with the given Options controlling its behavior.
pub fn new(options: Options) -> Self {
Logger { options: options }
}
}
impl Log for Logger {
fn enabled(&self, metadata: &Metadata) -> bool {
metadata.level() <= self.options.max_level
}
fn log(&self, record: &Record) {
if record.level()
> self
.options
.filters
.max_level_for(record.module_path().unwrap_or(""))
{
return;
}
let res = write!(
(self.options.output_factory)(),
"{}\n",
format_log_record(record)
);
if self.options.panic_on_output_failure {
if let Err(e) = res {
panic!("Failed to write log output: {}", e);
} else {
return;
}
}
if self.options.always_flush {
self.flush();
}
}
fn flush(&self) {
let res = (self.options.output_factory)().flush();
if self.options.panic_on_output_failure {
if let Err(e) = res {
panic!("Failed to flush log output: {}", e);
}
}
}
}
/// Try to set up a new global Logger, with the given Options controlling its
/// behavior, returning a standard error if doing so fails in some way.
pub fn try_init(options: Options) -> Result<()> {
let logger = Logger::new(options);
log::set_max_level(logger.options.max_level);
log::set_boxed_logger(Box::new(logger))?;
Ok(())
}
/// This is a shortcut which just calls try_init(), but implicitly unwraps the
/// resulting error. For applications which initialize a Logger first thing in
/// main(), this is probably a reasonable choice.
pub fn init(options: Options) {
try_init(options).unwrap();
}