Lib.rs

Cargo Features

[dependencies]
slog = { version = "2.8.2", default-features = false, features = ["nested-values", "dynamic-keys", "std", "nothreads", "anyhow", "parking_lot_0_12", "max_level_off", "max_level_info", "max_level_trace", "release_max_level_error", "release_max_level_info", "release_max_level_trace"] }

default = nested-values, std

These default features are set whenever slog is added without default-features = false somewhere in the dependency tree.

nested-values default

Support nesting values in log messages using serde
Using this is recommended to improve the detail of log messages.
Without it, only flat values like numbers and strings can be logged.
This requires the underlying logger to support this feature,
usually requiring a nested-values feature flag on the logging backend.

Enables erased-serde ^0.3 and serde_core

serde_core:

Depending on serde_core rather than serde reduces compile times (added in serde v1.0.200)

Affects slog::Serializer.emit_serde, slog::SerdeValue, slog::Serde…

dynamic-keys

DANGER: Use a String for slog::Key insated of &'static str
This is discouraged, becauase it can break other libraries relying on slog.
If you really need to dynamically allocate keys, you can use String::leak to achieve the same functionality without breaking other libraries.

std default

Require the standard library.

Enables std of optional anyhow and optional serde_core

Affects slog::MutexDrainError…

nothreads

DANGER: Remove the Send + Sync bound from the default logger and drain.

This feature is highly discouraged, because it could break other libraries relying on slog.
It is possible to achieve the same functionality by using a custom drain parameter to slog::Logger,
which will not break other libraries and avoids the overhead of an Arc.

anyhow

Implement slog::Value for anyhow::Error

Enables anyhow

parking_lot_0_12

Implement slog::Drain for parking_lot::Mutex.

Each version of parking_lot has a separate feature name, so that multiple versions of parking_lot can be supported at once without causing conflicts. This works because Cargo supports depending on multiple versions of the same crate, and Rust considers parking_lot_0_12::Mutex and parking_lot1::Mutex as completely different types.

Compatibility Guarantees: New versions of parking_lot can be added in a patch version of slog (2.8.1 -> 2.8.2)

Support for an old version of parking_lot will be reatined as long as reasonably possible, and only removed if it causes significant issues or is known to be severely buggy. In the exceptional event that support for an old version is removed, it will only happen in a slog minor version upgrade (2.8 -> 2.9), never in a patch version upgrade.

A hypothetical parking_lot v1.0 release would be named parking_lot1 rather than parking_lot_1.

Enables parking_lot

max_level_off

Control the log level at compile-time

max_level_error max_level_warn max_level_info

max_level_debug max_level_trace

release_max_level_off release_max_level_error

release_max_level_warn release_max_level_info

release_max_level_debug release_max_level_trace