slog

This is the biggest slog release since 2.0. It fully preserves compatibility with prior releases.

Highlights

• Enables the nested-values feature by default. The next major release of slog_json, slog_term, etc should also enable this feature by default.
• Added Logger::flush and Drain::flush methods.
• Improved support for logging errors
  • Have # log specifier transparently support & references to error
  • Implement slog::Value for Box<dyn std::error::Error> and anyhow::Error
• Define a prelude module for common imports
• Upgraded to Rust 2018 and require Rust 1.61
  • Deprecate the old slog_log! macros in favor of slog::log!
• Many internal improvements & bug fixes

Changed

• Enables the nested-values feature by default.
• Updated to Rust 2018
  • NOTE: Old 2015 crates will still work because of excellent 2015/2018 compatibility
• Bump MSRV to 1.61
  • This is already required for erased-serde, syn, serde_core, and many other important crates in the rust ecosystem.
• Update erased-serde from v0.3 to v0.4
• Depend on serde_core rather than serde to reduce compile times.

Added

• Added a Logger::flush and Drain::flush methods
  • Since this is a new method, not all drains implement it. Calling it on an unsupported drain will give an error
• Define a prelude module for common imports. Replace use slog::{Serde, Logger, info, debug, trace} with use slog::prelude::*
• Optionally implement Drain for parking_lot::Mutex. This is noticeably faster than std::sync::Mutex, is smaller, and avoids poisoning.
  • This feature has a separate name per version to allow supporting multiple versions of parking_lot at once. The current version (v0.12) has feature name parking_lot_0_12
• Implement slog::Value for dyn std::error::Error and Box<dyn std::error:Error (along with the Send/Sync versions).
• Optionally implement slog::Value for anyhow::Error (requires anyhow feature)
• Add ErrorRef wrapper to enable logging error references (PR #327)
  • The # error formatter in macros was updated to automatically select ErrorValue or ErrorRef (PR #328)
• Add emit_bytes method (PR #290)
  • Control formatting using BytesKind enum
• Implement Value for std::borrow::Cow

Deprecated

• Deprecate old prefixed macros like slog_log. Rust 2018 macro paths like slog::log! make these unnecessary.

Fixed

• Fix logging of references to errors (resolved by introduction of ErrorRef in PR #327)
• Take advantage of the fact that in 1.81 std::error::Error has been moved to core. On this rust version, slog now supports the error trait without requiring std.
• Add #[must_use] to most public types, including slog::Logger, slog::OwnedKV, and slog::FnValue.
• Give a descriptive error when the nested-values feature is unsupported.
• Alias the slog::Never type to std::convert::Infallible, fixing issue #209.
• doc: Fix typo in slog::Value docs (issue #335)
  • Thank you to @larswirzenius for noticing this!
• doc: Fix "lazy continuation" in slog::Logger doc
  • This mistake was caught by a new lint #[warn(clippy::doc_lazy_continuation)]
• Fix some internal warnings
  • Example: Avoid the new #[warn(unexpected_cfgs)] lint.
  • The crate almost passes clippy::pedantic now, except for a few very verbose lints like clippy::must-use-candidate
  • None of these changes should affect user crates
• Stop requiring the serde_derive crate to implement the nested-values feature. We depend on the new serde_core instead of even requiring serde.
• The nested-values feature no longer requires serde/std (was a mistake).
• Always support 128-bit integers, even on the wasm32-unknown-emscripten target.
• Fix support for feature="nothreads"
  • Internal refactoring to make different feature combos much easier (PR #301)
• Switch from Travis CI to Github Actions (fixes #294)
  • rustfmt --check now run by default
  • Require clippy to succeed without warnings
  • Require all feature combinations to pass tests.
    • Make exception for nested-values feature on MSRV (1.49), because erased-serde dependency requires edition="2021" (needs 1.56)
• Fix # format when not used as a last argument.
• Fix duplicate AsRef<str> implementations when using dynamic-keys feature.
• Fix incorrect 'long' name for slog::Level::Warning (fixes issue #282)

Final release waiting for more feedback on PR #346,
which would make nested-values a default feature.

Update to Rust 2018
Enable Github Actions

Significant internal refactoring and cleanup.

Some minor improvements:

• Implement Hash for Level and FilterLevel
• Add #% for alternate display of the value part
• Implement Eq for dynamic Keys
• Add emit_error to Serializer, # for serializing foreign errors, and
  impl Value for std::io::Error

Retroactively tagged by Techcable

• Restored parsing of Level and FilterLevel truncated names

• Added parsing of Level and FilterLevel short names

• Added FilterLevel::accepts
• Added as_str, as_short_str and Display to FilterLevel

• disable support for i128/u128 types if rustc is old

• Implement Value for 128 bit integers
• Add support 2018-style macro imports
  • WARNING: This is a breaking change that we couldn't avoid. Users using explicitly macro import (like #[macro_use(slog_o)]) must add __slog_builtin to the import list.
• Bump minimum supported Rust version to 1.26

• impl Value for SocketAddr

• Revert broken changes:
  • Make ? and % formatters in kv! more flexible
  • Export local inner macros to help with Rust 2018 testing

• Export local inner macros to help with Rust 2018 testing
• Stabilize Record::new
• Make ? and % formatters in kv! more flexible

• Fix (again) problems introduced by 2.2.1

• Fix problems introduced by 2.2.1

• Add is_x_enabled() for queering (imprecise) log-level

Added

• Support for nested-values through emit_serde, behind nested-values feature flag, disabled by default for backward compatibility. Note: Consider unstable for the time being.
• Support for dynamic key (String vs &'static str), behind dynamic-keys feature flag, disabled by default for backward compatibility. Note: Consider unstable for the time being.

Changed

• #[allow(dead_code) on unused log statements

Changed

• Impl Value for std::path::Display

Changed

• Remove unnecessary 'static bound on FnValue

Changed

• Update README

Changed

• Fix for https://github.com/rust-lang/rust/pull/42125

Changed

• Relicense under MPL/Apache/MIT

Fixed

• Documentation improvements

Fixed

• Documentation fixes

Fixed

• Compile time logging level filtering

Changed (since v1; bigger picture)

• Unified and simplified logging macros structure and ordering.
• Added logging Record tags.
• Refactored key-value pairs traits and structures and overall handling.
  • It's now possible to impl KV for MyStruct.
  • kv! can be used to create on stack key-value list.
  • KV-implementing data can appear on the key-value list directly.
• Support chaining of OwnedKVLists. Existing Logger can be used as a Drain to allow custom handling logic for a part of the logging hierarchy.
• Added associated Ok type to Drain.
• Support for Drains unwind safety.
• Refactored Record to optimize performance on async operations.
• slog-extra has been renamed to slog-async since that's the only functionality it contained.
• slog-stream is obsoleted and won't be used in slog v2 at all. It was a wrong abstraction. Decorators functionality was moved to slog-term.
• slog-term provides open Decorator traits to allow multiple terminal / file writing backends.
• slog-term default Decorators use term crate and should work correctly on all supported OSes.
• DrainExt has been removed and utility methods moved directly to Drain
• slog-stdlog utilizes slog-scope directly.
• Support for "typed" Loggers to allow squeezing last drops of performance possible, at the cost of T in Logger<T>.

Added

• Support for fmt::Display values with % in kv!

Changed

• Added support for own KV and Value implementations
• Streamlined the formatting syntax for log! and friends; BREAKING
• Lazy values need explicit FnValue wrapper; BREKING

Added

• kv! macro

Fixes

• Bunch of trait-related fixes

Fixed

• Require MapErr and Filter to be UnwindSafe

Changed

• Make Logger::root return "erased" version
• Introduce Logger::root_typed for "non-erased" Logger creation

Fixed

• fmt::Debug for MutexDrainError

Changed

• Parametrize Logger over the Drain it holds and introduce "erased" version
• Enforcing UnwindSafe Drains for Loggers
• Refactored key-value pairs traits and structures
• Renamed some types
• Support chaining of OwnedKVLists
• Added associated Ok type to Drain
• Refactored Record to optimize performance on async operations
• Minimal rustc version required: 1.15.0
• DrainExt has been removed and utility methods moved directly to Drain

Added

• Macros to create OwnedKV and BorrowedKV
• Logger implements Drain

Changed

• Order of key-value pairs is now strictly defined

Added

• Logger implements Drain

Deprecated

• Creation of OwnedKeyValueList

Fixed

• Fix an invalid syntax exposed by nightly rust change (Issue #103)

Changed

• Updated documentation

Deprecated

• OwnedKeyValueList::id

Added

• slog_o as an alternative name for o

Fixed

• Cargo publishing mistake.

Changed

• BREAKING: Removed default Send+Sync from Drain

Added

• OwnedKeyValueList::id for owned key value unique identification

Changed

• BREAKING: Serializer takes key : &'static str now

Fixed

• Corner cases in info!(...) and other macros

Changed

• BREAKING: Rewrite handling of owned values.

Fixed

• use std in o!

Added

• Implement fmt::Debug for Logger

First stable release.