Struct RequestId 

pub struct RequestId(/* private fields */);

A per-connection (or per-request) identifier, carried as a span field so every line emitted underneath is attributable without repeating it.

Why not a UUID

A UUID costs a dependency, 16 bytes and a formatting allocation to say something a 64-bit integer already says. This is a process seed in the high 32 bits and a monotonic counter in the low 32, rendered as 16 hex digits. Two ids from the same process never collide; two ids from different runs of the same server collide only if both start within the same microsecond and reach the same counter value, which is not a property a log correlation needs.

It is Copy, it is one fetch_add(Relaxed) to mint, and its Display writes into the formatter without allocating.

Implementations

impl RequestId

pub fn next() -> RequestId

Mint the next id. One relaxed atomic increment; never blocks.

pub fn get(&self) -> u64

The raw value, for a caller that wants to store it as a number.

Trait Implementations

impl Clone for RequestId

fn clone(&self) -> RequestId

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for RequestId

impl Debug for RequestId

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Display for RequestId

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Eq for RequestId

impl Hash for RequestId

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for RequestId

fn cmp(&self, other: &RequestId) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for RequestId

fn eq(&self, other: &RequestId) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for RequestId

fn partial_cmp(&self, other: &RequestId) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for RequestId