Level-at-least

Create a RecordPredicate that returns true when a record level is greater than or equal to a minimum threshold. This is the main helper for severity-based filtering.

Interface

pub fn level_at_least(min_level : Level) -> RecordPredicate {}

input

• min_level : Level - The lowest level that should remain enabled.

output

• RecordPredicate - Predicate that keeps records whose priority() is at least the given minimum.

Explanation

Detailed rules explaining key parameters and behaviors

• Matching is based on Level::priority(), not string comparison.
• Records at the exact same level as min_level are included.
• This helper is useful when a sink or child logger needs a stricter threshold than the parent logger.
• It composes cleanly with all_of(...) and any_of(...).

How to Use

Here are some specific examples provided.

When Keep Warnings And Errors

When a logger should keep only important records:

let logger = Logger::new(console_sink())
  .with_filter(level_at_least(Level::Warn))

In this example, Warn and Error records continue through the filter.

When Combine With Target Routing

When both severity and namespace matter:

let predicate = all_of([
  target_has_prefix("service.api"),
  level_at_least(Level::Info),
])

In this example, the predicate can be reused by multiple loggers or sinks.

Error Case

e.g.:

• If min_level is Level::Trace, the predicate effectively allows all normal log records.

• If min_level is higher than the record level, the predicate returns false without modifying the record.

Notes

1. Use this helper when you want filtering logic to remain explicit instead of embedding level checks inline.

2. This predicate is separate from a logger's own min_level, so both can be combined.