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//! # logsley //! This is an opinionated Rust logging library. //! //! ## Features //! - Configure the logger with one function call //! - Thread and task scoped variables //! - See logging output from tests //! - Works with libraries that use //! [`log`](https://crates.io/crates/log), //! [`slog`](https://crates.io/crates/slog), //! [`slog-scope`](https://crates.io/crates/slog-scope), //! and [`slog-scope-futures`](https://crates.io/crates/slog-scope-futures). //! - Logs JSON by default. //! Set `DEV_LOG_FORMAT=full` env var to get pretty output in your terminal. //! - Adjust logging verbosity of modules with simple string parameter, //! and override it with the `RUST_LOG env var.` //! Example: `RUST_LOG=some::spammy::module=warn,my::buggy::module=trace`. //! See [`slog-envlogger`](https://docs.rs/slog-envlogger/2.2.0/slog_envlogger/) for details. //! - Approved by Sir Robin of Logsley:<br/> //! ![Cary Elwes as Robin Hood in the film Robin Hood Men in Tights (1993)](robinhood.jpg) //! //! //! ## Limitations //! - Uses macros //! //! ## Examples //! ```rust //! // You should do logging like this. //! //! # fn f() { //! let _global_logger_guard = //! logsley::configure("info").unwrap(); //! logsley::thread_scope("main", || { //! // Log named values: //! logsley::error!("err {}", 1; "x" => 2); //! // {"time_ns":1604899904064111000, //! // "time":"2020-11-08T21:31:44.064-08:00", //! // "module":"opinion", //! // "level":"ERROR", //! // "message":"err 1", //! // "thread":"main", //! // "x":2} //! logsley::warn!("warn {}", 1; "x" => 2); //! logsley::info!("info {}", 1; "x" => 2); //! logsley::debug!("debug {}", 1; "x" => 2); //! logsley::trace!("trace {}", 1; "x" => 2); //! //! // Log simple messages: //! log::info!("log {}", 1); //! // {"time_ns":1604899904065070000, //! // "time":"2020-11-08T21:31:44.065-08:00", //! // "module":"opinion", //! // "level":"INFO", //! // "message":"log 1", //! // "thread":"main"} //! //! std::thread::spawn(|| { //! logsley::thread_scope("thread1", || { //! logsley::info!("in thread {}", 1; "x" => 2); //! })}) //! .join() //! .unwrap(); //! // {"time_ns":1604899904065111000, //! // "time":"2020-11-08T21:31:44.065-08:00", //! // "module":"opinion", //! // "level":"INFO", //! // "message":"in thread 1", //! // "thread":"thread1", //! // "x":2} //! //! async_std::task::block_on( //! logsley::task_scope("task1", async move { //! logsley::info!( //! "logsley in task {}", 1; "x" => 2); //! })); //! // {"time_ns":1604899904065241000, //! // "time":"2020-11-08T21:31:44.065-08:00", //! // "module":"opinion", //! // "level":"INFO", //! // "message":"logsley in task 1", //! // "task":"task1", //! // "thread":"main", //! // "x":2} //! //! panic!("uhoh"); //! // {"time_ns":1604899904955593000, //! // "time":"2020-11-08T21:31:44.955-08:00", //! // "module":"log_panics", //! // "level":"ERROR", //! // "message":"thread 'main' panicked at 'uhoh': examples/opinion.rs:30\n //! // 0: backtrace::backtrace::libunwind::trace\n //! // at /.../backtrace-0.3.54/src/backtrace/libunwind.rs:90:5\n //! // backtrace::backtrace::trace_unsynchronized\n //! // at /.../backtrace-0.3.54/src/backtrace/mod.rs:66:5\n //! // 1: backtrace::backtrace::trace\n //! // at /.../backtrace-0.3.54/src/backtrace/mod.rs:53:14\n //! // 2: backtrace::capture::Backtrace::create\n //! // at /.../backtrace-0.3.54/src/capture.rs:176:9\n //! // 3: backtrace::capture::Backtrace::new\n //! // at /.../backtrace-0.3.54/src/capture.rs:140:22\n //! // 4: log_panics::init::{{closure}}\n //! // at /.../log-panics-2.0.0/src/lib.rs:52:25\n //! // 5: std::panicking::rust_panic_with_hook\n //! // at /.../library/std/src/panicking.rs:581:17\n //! // 6: std::panicking::begin_panic::{{closure}}\n //! // at /.../library/std/src/panicking.rs:506:9\n //! // 7: std::sys_common::backtrace::__rust_end_short_backtrace\n //! // at /.../library/std/src/sys_common/backtrace.rs:153:18\n //! // 8: std::panicking::begin_panic\n //! // at /.../library/std/src/panicking.rs:505:12\n //! // 9: opinion::main::{{closure}}\n //! // at examples/opinion.rs:30:9\n //! // 10: slog_scope::scope\n //! // at /.../slog-scope-4.3.0/lib.rs:248:5\n //! // 11: logsley::thread_scope\n //! // at src/lib.rs:179:5\n //! // 12: opinion::main\n //! // at examples/opinion.rs:5:5\n //! // 13: core::ops::function::FnOnce::call_once\n //! // at /.../library/core/src/ops/function.rs:227:5\n //! // 14: std::sys_common::backtrace::__rust_begin_short_backtrace\n //! // at /.../library/std/src/sys_common/backtrace.rs:137:18\n //! // 15: std::rt::lang_start::{{closure}}\n //! // at /.../library/std/src/rt.rs:66:18\n //! // 16: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once\n //! // at /.../library/core/src/ops/function.rs:259:13\n //! // std::panicking::try::do_call\n //! // at /.../library/std/src/panicking.rs:381:40\n //! // std::panicking::try\n //! // at /.../library/std/src/panicking.rs:345:19\n //! // std::panic::catch_unwind\n //! // at /.../library/std/src/panic.rs:382:14\n //! // std::rt::lang_start_internal\n //! // at /.../library/std/src/rt.rs:51:25\n //! // 17: std::rt::lang_start\n //! // at /.../library/std/src/rt.rs:65:5\n //! // 18: _main\n", //! // "thread":"main"} //! }); //! } //! ``` //! For a runnable example, see [examples/opinion.rs](examples/opinion.rs). //! //! Set the default log level to `info`. //! The program will emit log messages with level `info` and higher. //! ```rust //! let _global_logger_guard = logsley::configure("info"); //! log::error!("emitted"); //! log::warn!("emitted"); //! log::info!("emitted"); //! log::debug!("not emitted"); //! log::trace!("not emitted"); //! ``` //! //! Set the default log level to `info` and set the level for `chatty::module1` to `warn`. //! ```rust //! let _global_logger_guard = //! logsley::configure("info,chatty::module1=warn"); //! ``` //! //! Use the environment variable to override default log level. //! `module1` still gets its special log level. //! ```rust //! std::env::set_var("RUST_LOG", "debug"); //! let _global_logger_guard = //! logsley::configure("info,module1=warn"); //! ``` //! //! Use the environment variable to set `module1` to `debug`. //! ```rust //! std::env::set_var("RUST_LOG", "module1=debug"); //! let _global_logger_guard = //! logsley::configure("info"); //! ``` //! //! ## Documentation //! https://docs.rs/logsley //! //! ## Alternatives //! - [log](https://crates.io/crates/log) //! - [log-panics](https://crates.io/crates/log-panics) //! - [slog](https://crates.io/crates/slog) //! - [slog-async](https://crates.io/crates/slog-async) //! - [slog-envlogger](https://crates.io/crates/slog-envlogger) //! - [slog-json](https://crates.io/crates/slog-json) //! - [slog-scope](https://crates.io/crates/slog-scope) //! - [slog-scope-futures](https://crates.io/crates/slog-scope-futures) //! - [slog-stdlog](https://crates.io/crates/slog-stdlog) //! - [slog-term](https://crates.io/crates/slog-term) //! //! ## Release Process //! 1. Edit `Cargo.toml` and bump version number. //! 1. Run `./release.sh` //! //! ## Changelog //! - v0.1.5 - Rename `OutputFormat::JSON` to `Json` to satisfy nightly clippy. //! - v0.1.4 - Update docs. //! - v0.1.3 - Fix missing slog_scope::logger error //! - v0.1.2 - Fix panic in configure_for_test //! - v0.1.1 - Make example code fit in crates.io's 60-column code views. //! - v0.1.0 - First published version //! //! ## TODO //! - DONE - Try to make this crate comply with the [Rust API Guidelines](https://rust-lang.github.io/api-guidelines/). //! - DONE - Include Readme.md info in the crate's docs. //! - DONE - Make the repo public //! - DONE - Set up continuous integration tests and banner. //! - https://gitlab.com/mattdark/firebase-example/blob/master/.gitlab-ci.yml //! - https://medium.com/astraol/optimizing-ci-cd-pipeline-for-rust-projects-gitlab-docker-98df64ae3bc4 //! - https://hub.docker.com/_/rust //! - DONE - Add some documentation tests //! - https://doc.rust-lang.org/rustdoc/documentation-tests.html //! - https://doc.rust-lang.org/stable/rust-by-example/testing/doc_testing.html //! - DONE - Publish to creates.io //! - DONE - Read through https://crate-ci.github.io/index.html //! - DONE - Add and update a changelog //! - Update it manually //! - https://crate-ci.github.io/release/changelog.html //! - Get a code review from an experienced rustacean //! - Add features: threads, futures, term #![forbid(unsafe_code)] #[doc(hidden)] pub mod reexports { pub mod slog_scope { pub use slog_scope::logger; } } #[derive(Clone, Debug, PartialEq)] pub enum OutputFormat { Json, Compact, Full, Plain, } /// Configure `log` and `slog` to emit JSON to stdout. /// /// Applies global and per-module filtering rules from `filters` and overrides them with /// rules from the `RUST_LOG` environment variable. /// The `filters` syntax is quite expressive. /// See the [slog_envlogger docs](https://docs.rs/slog-envlogger/2.2.0/slog_envlogger/) /// /// You can set the `DEV_LOG_FORMAT` environment variable to one of: /// - `"json"` or `""` to log in JSON format. /// - `"compact"` to print scope variables on their own line and indent log messages emitted inside /// the scope. /// - `"full"` to print scope variables on every line, with color. /// - `"plain"` to print without color. /// /// Release binaries always log JSON. Only debug binaries check the `DEV_LOG_FORMAT` env var. /// /// Examples: /// - Set the default log level to `info`. /// The program will emit log messages with level `info` and higher. /// ``` /// # fn f() { /// let _global_logger_guard = logsley::configure("info"); /// logsley::info!("a message"; "some_data" => 123, "other_data" => "val1"); /// slog::info!(slog_scope::logger(), "a message"; "some_data" => 123, "other_data" => "val1"); /// log::info!("a message; some_data={} other_data={}", 123, "val1"); /// log::debug!("some details"); // Not emitted /// # } /// ``` /// - Set the default log level to `info` and set the level for `chatty::module1` to `warn`. /// ``` /// # fn f() { /// let _global_logger_guard = logsley::configure("info,chatty::module1=warn"); /// # } /// ``` /// - Use the environment variable to override default log level. /// `module1` still gets its special log level. /// ``` /// # fn f() { /// std::env::set_var("RUST_LOG", "debug"); /// let _global_logger_guard = logsley::configure("info,module1=warn"); /// # } /// ``` /// - Use the environment variable to set `module1` to `debug`. /// ``` /// # fn f() { /// std::env::set_var("RUST_LOG", "module1=debug"); /// let _global_logger_guard = logsley::configure("info"); /// # } /// ``` /// /// Example output: /// ```json /// {"time_ns":1585851354242507000, "time":"2020-04-02T18:15:54.242521000Z", \ /// "module":"mod1","level":"ERROR","message":"msg1", "thread":"main","x":2} /// ``` pub fn configure( filters: &str, ) -> Result<slog_scope::GlobalLoggerGuard, Box<dyn std::error::Error>> { let format = OutputFormat::Json; #[cfg(debug_assertions)] // Include the following statement in debug binaries, not release. let dev_log_format: String = std::env::var("DEV_LOG_FORMAT").unwrap_or_default(); let format = match dev_log_format.as_ref() { "" | "json" => format, "compact" => OutputFormat::Compact, "full" => OutputFormat::Full, "plain" => OutputFormat::Plain, s => panic!("Invalid DEV_LOG_FORMAT env var value {:?}", s), }; configure_inner(filters, format) } #[derive(Debug, PartialEq, Clone)] pub struct ChangingConfigNotAllowed {} impl std::fmt::Display for ChangingConfigNotAllowed { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> { write!(f, "ChangingConfigNotAllowed") } } impl std::error::Error for ChangingConfigNotAllowed {} /// Configures `log` and `slog` to emit to stdout with "plain" format. /// Can be called multiple times from different threads. /// Each call leaks a `GlobalLoggerGuard` which contains only a `bool`. pub fn configure_for_test( filters: &str, format: OutputFormat, ) -> Result<(), ChangingConfigNotAllowed> { let mut hasher = std::collections::hash_map::DefaultHasher::new(); std::hash::Hasher::write(&mut hasher, filters.as_bytes()); let filters_hash = std::hash::Hasher::finish(&hasher); static TEST_CONFIG: once_cell::sync::Lazy< std::sync::Mutex<Option<(u64, OutputFormat, slog_scope::GlobalLoggerGuard)>>, > = once_cell::sync::Lazy::new(|| std::sync::Mutex::new(None)); let mut test_config_lock = TEST_CONFIG.lock().unwrap(); match test_config_lock.as_ref() { None => { // log::set_max_level(log::LevelFilter::Trace); let guard = configure_inner(filters, OutputFormat::Plain).unwrap(); *test_config_lock = Some((filters_hash, format, guard)); Ok(()) } Some(tuple) if tuple.0 == filters_hash && tuple.1 == format => Ok(()), _ => Err(ChangingConfigNotAllowed {}), } } fn configure_inner( filters: &str, output_format: OutputFormat, ) -> Result<slog_scope::GlobalLoggerGuard, Box<dyn std::error::Error>> { let _time_fn = |_: &slog::Record| chrono::Utc::now().to_rfc3339_opts(chrono::SecondsFormat::Nanos, true); let _time_ns_fn = |_: &slog::Record| { std::time::SystemTime::now() .duration_since(std::time::SystemTime::UNIX_EPOCH) // Use default Duration (0 seconds) if system time is before epoch. .unwrap_or_default() // Nanoseconds overflow u64 in the year 2554. .as_nanos() as u64 }; let _module_fn = |record: &slog::Record| record.module(); let _level_fn = |record: &slog::Record| match record.level() { slog::Level::Critical => "ERROR", slog::Level::Error => "ERROR", slog::Level::Warning => "WARN", slog::Level::Info => "INFO", slog::Level::Debug => "DEBUG", slog::Level::Trace => "TRACE", }; let _message_fn = |record: &slog::Record| record.msg().to_string(); let _time_fn = |_record: &slog::Record| { chrono::Local::now().to_rfc3339_opts(chrono::SecondsFormat::Millis, true) }; let _write_timestamp_fn = |w: &mut dyn std::io::Write| { w.write( chrono::Local::now() .to_rfc3339_opts(chrono::SecondsFormat::Millis, true) .as_bytes(), ) .map(|_| ()) }; let drain: Box<dyn slog::Drain<Ok = (), Err = std::io::Error> + Send> = match output_format { OutputFormat::Json => { Box::new( slog_json::Json::new(std::io::stdout()) .add_key_value(slog::o!( // Fields are in reverse order. "message" => slog::FnValue(_message_fn), "level" => slog::FnValue(_level_fn), "module" => slog::FnValue(_module_fn), "time" => slog::FnValue(_time_fn), "time_ns" => slog::FnValue(_time_ns_fn), // TODONT(mleonhard) Don't include 'process' or 'host'. // Supervisor and collector will add these values and // will not trust any values already present. )) .build(), ) } OutputFormat::Compact => Box::new( slog_term::CompactFormat::new(slog_term::TermDecorator::new().build()) .use_custom_timestamp(_write_timestamp_fn) .build(), ), OutputFormat::Full => Box::new( slog_term::FullFormat::new(slog_term::TermDecorator::new().build()) .use_custom_timestamp(_write_timestamp_fn) .build(), ), OutputFormat::Plain => Box::new( slog_term::FullFormat::new(slog_term::PlainDecorator::new(std::io::stdout())) .use_custom_timestamp(_write_timestamp_fn) .build(), ), }; let drain = slog_envlogger::LogBuilder::new(drain) .parse(filters) // Add any level overrides from environment variable .parse(&match std::env::var("RUST_LOG") { Ok(x) => Ok(x), Err(std::env::VarError::NotPresent) => Ok(String::new()), Err(x) => Err(x), }?) .build(); let drain = slog::Fuse(std::sync::Mutex::new(drain)); let drain = slog::Fuse( slog_async::Async::new(drain) .chan_size(1024) .overflow_strategy(slog_async::OverflowStrategy::Block) .build(), ); let logger = slog::Logger::root(drain, slog::o!()); let _guard = slog_scope::set_global_logger(logger); slog_stdlog::init()?; log_panics::init(); Ok(_guard) } pub fn thread_scope<SF, R>(name: &str, f: SF) -> R where SF: FnOnce() -> R, { let _name = name; let logger = slog_scope::logger().new(slog::o!("thread" => String::from(_name))); slog_scope::scope(&logger, f) } pub fn task_scope<F>(name: &'static str, f: F) -> slog_scope_futures::SlogScope<slog::Logger, F> where F: std::future::Future, { let _name = name; slog_scope_futures::SlogScope::new(slog_scope::logger().new(slog::o!("task" => _name)), f) } #[macro_export] macro_rules! error ( ($($args:tt)+) => { slog::error!(logsley::reexports::slog_scope::logger(), $($args)+) }; ); #[macro_export] macro_rules! warn ( ($($args:tt)+) => { slog::warn!(logsley::reexports::slog_scope::logger(), $($args)+) }; ); #[macro_export] macro_rules! info ( ($($args:tt)+) => { slog::info!(logsley::reexports::slog_scope::logger(), $($args)+) }; ); #[macro_export] macro_rules! debug ( ($($args:tt)+) => { slog::debug!(logsley::reexports::slog_scope::logger(), $($args)+) }; ); #[macro_export] macro_rules! trace ( ($($args:tt)+) => { slog::trace!(logsley::reexports::slog_scope::logger(), $($args)+) }; );