Enum opentelemetry::trace::SpanKind
source · pub enum SpanKind {
Client,
Server,
Producer,
Consumer,
Internal,
}
Expand description
SpanKind
describes the relationship between the Span, its parents,
and its children in a Trace
. SpanKind
describes two independent
properties that benefit tracing systems during analysis.
The first property described by SpanKind
reflects whether the Span
is a remote child or parent. Span
s with a remote parent are
interesting because they are sources of external load. Span
s with a
remote child are interesting because they reflect a non-local system
dependency.
The second property described by SpanKind
reflects whether a child
Span
represents a synchronous call. When a child span is synchronous,
the parent is expected to wait for it to complete under ordinary
circumstances. It can be useful for tracing systems to know this
property, since synchronous Span
s may contribute to the overall trace
latency. Asynchronous scenarios can be remote or local.
In order for SpanKind
to be meaningful, callers should arrange that
a single Span
does not serve more than one purpose. For example, a
server-side span should not be used directly as the parent of another
remote span. As a simple guideline, instrumentation should create a
new Span
prior to extracting and serializing the span context for a
remote call.
To summarize the interpretation of these kinds:
SpanKind | Synchronous | Asynchronous | Remote Incoming | Remote Outgoing |
---|---|---|---|---|
Client | yes | yes | ||
Server | yes | yes | ||
Producer | yes | yes | ||
Consumer | yes | yes | ||
Internal |
Variants§
Client
Indicates that the span describes a synchronous request to
some remote service. This span is the parent of a remote Server
span and waits for its response.
Server
Indicates that the span covers server-side handling of a
synchronous RPC or other remote request. This span is the child of
a remote Client
span that was expected to wait for a response.
Producer
Indicates that the span describes the parent of an
asynchronous request. This parent span is expected to end before
the corresponding child Consumer
span, possibly even before the
child span starts. In messaging scenarios with batching, tracing
individual messages requires a new Producer
span per message to
be created.
Consumer
Indicates that the span describes the child of an
asynchronous Producer
request.
Internal
Default value. Indicates that the span represents an internal operation within an application, as opposed to an operations with remote parents or children.