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// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
//! Public constants for cachet telemetry field names and event values.
//!
//! Use these constants to filter or match cachet events in a custom
//! `tracing_subscriber::Layer`. All cachet events are emitted with
//! `FIELD_NAME`, `FIELD_EVENT`, and `FIELD_DURATION_NS` fields.
//!
//! # Example
//!
//! ```ignore
//! use cachet::telemetry::attributes;
//!
//! // In a tracing Visit impl, match on field values:
//! if event_value == attributes::EVENT_HIT {
//! // handle cache hit
//! }
//! ```
/// Tracing target prefix for all cachet telemetry events.
///
/// All cachet telemetry events use the module path as the tracing target (e.g.,
/// `cachet::telemetry::cache`), which starts with this prefix. Consumers can
/// filter for all cachet events using prefix matching with `tracing_subscriber`:
/// ```ignore
/// use tracing_subscriber::filter;
/// let filter = filter::Targets::new()
/// .with_target(cachet::telemetry::attributes::TARGET, tracing::Level::DEBUG);
/// ```
pub const TARGET: &str = "cachet";
// -- Field names --
/// Field name for the cache tier name.
pub const FIELD_NAME: &str = "cache.name";
/// Field name for the cache event type.
pub const FIELD_EVENT: &str = "cache.event";
/// Field name for the operation duration in nanoseconds.
pub const FIELD_DURATION_NS: &str = "cache.duration_ns";
// -- Event values (emitted in the `cache.event` field) --
/// Cache entry was found and valid.
pub const EVENT_HIT: &str = "cache.hit";
/// Cache entry was not found.
pub const EVENT_MISS: &str = "cache.miss";
/// Cache entry was found but expired.
pub const EVENT_EXPIRED: &str = "cache.expired";
/// An error occurred during a get operation.
pub const EVENT_GET_ERROR: &str = "cache.get_error";
/// A fallback tier was consulted.
pub const EVENT_FALLBACK: &str = "cache.fallback";
/// An entry was successfully inserted.
pub const EVENT_INSERTED: &str = "cache.inserted";
/// An insert was rejected by the insert policy.
pub const EVENT_INSERT_REJECTED: &str = "cache.insert_rejected";
/// An error occurred during an insert operation.
pub const EVENT_INSERT_ERROR: &str = "cache.insert_error";
/// A key was successfully invalidated.
pub const EVENT_INVALIDATED: &str = "cache.invalidated";
/// An error occurred during an invalidate operation.
pub const EVENT_INVALIDATE_ERROR: &str = "cache.invalidate_error";
/// Cache was successfully cleared.
pub const EVENT_CLEARED: &str = "cache.cleared";
/// An error occurred during a clear operation.
pub const EVENT_CLEAR_ERROR: &str = "cache.clear_error";
/// A background refresh found data in the fallback tier.
pub const EVENT_REFRESH_HIT: &str = "cache.refresh_hit";
/// A background refresh did not find data in the fallback tier.
pub const EVENT_REFRESH_MISS: &str = "cache.refresh_miss";