Struct SpanGroup 

pub struct SpanGroup { /* private fields */ }

Represents a set of tracing::Spans for which latency information should be collected as a group. It is the unit of latency information collection.

Span definitions are created in the code using macros and functions from the Rust tracing library which define span callsites, i.e., the places in the code where spans are defined. As the code is executed, a span definition in the code may be executed multiple times – each such execution is a span instance. Span instances arising from the same span definition are grouped into SpanGroups for latency information collection. Latencies are collected using Histograms from the hdrhistogram library.

The grouping of spans for latency collection is not exactly based on the span definitions in the code. Spans at runtime are structured as a set of span trees that correspond to the nesting of spans from code execution paths. The grouping of runtime spans for latency collection should respect the runtime parent-child relationships among spans.

Thus, SpanGroups form a forest of trees where some pairs of span groups have a parent-child relationship, corresponding to the parent-child relationships of the spans associated with the span groups. This means that if SpanGroup A is the parent of SpanGroup B then, for each span that was assigned to group B, its parent span was assigned to group A.

The coarsest-grained grouping of spans is characterized by a callsite path – a callsite and the (possibly empty) list of its ancestor callsites based on the different runtime execution paths (see Span relationships). This is the default SpanGroup definition. Finer-grained groupings of spans can differentiate groups of spans with the same callsite path by taking into account values computed at runtime from the spans’ runtime Attributes.

This struct holds the following information:

• the name of the span definition that applies to all the spans in the span group
• an id that, together with its name, uniquely identifies the span group
• a props field that contains the list of name-value pairs (which may be empty) which is common to all the spans in the group
• a code_line field that contains the file name and line number where all the spans in the group were defined or, in case debug information is not available, the corresponding tracing::callsite::Identifier.
• a parent_id that is the id field of the parent span group, if any.
• its depth, i.e., the number of ancestor span groups this span group has

Implementations

impl SpanGroup

pub fn name(&self) -> &'static str

Returns the span group’s name.

pub fn id(&self) -> &str

Returns the span group’s ID.

pub fn code_line(&self) -> &str

Returns the span group’s file name and code line.

pub fn props(&self) -> &[(String, String)]

Returns the span group’s properties list.

This list can be empty as is the case with the default span grouper.

pub fn parent_id(&self) -> Option<&str>

Returns the ID of the span group’s parent.

pub fn depth(&self) -> usize

Returns the number of ancestor span groups this span group has.

Trait Implementations

impl Clone for SpanGroup

fn clone(&self) -> SpanGroup

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SpanGroup

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

Formats the value using the given formatter.

impl Hash for SpanGroup

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

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 SpanGroup

fn cmp(&self, other: &SpanGroup) -> 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.

impl PartialEq for SpanGroup

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for SpanGroup

fn partial_cmp(&self, other: &SpanGroup) -> 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 Eq for SpanGroup

impl StructuralPartialEq for SpanGroup