Class PassThroughPropagator
java.lang.Object
io.opentelemetry.api.incubator.propagation.PassThroughPropagator
- All Implemented Interfaces:
TextMapPropagator
A
TextMapPropagator
which can be configured with a set of fields, which will be extracted
and stored in Context
. If the Context
is used again to inject, the values will be
injected as-is. This TextMapPropagator
is appropriate for a service that does not need to
participate in telemetry in any way and provides the most efficient way of propagating incoming
context to outgoing requests. In almost all cases, you will configure this single TextMapPropagator
when using OpenTelemetry.propagating(ContextPropagators)
to create an OpenTelemetry
that only propagates. Similarly, you will never need this
when using the OpenTelemetry SDK to enable telemetry.-
Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic TextMapPropagator
Returns aTextMapPropagator
which will propagate the givenfields
from extraction to injection.static TextMapPropagator
Returns aTextMapPropagator
which will propagate the givenfields
from extraction to injection.<C> Context
extract
(Context context, C carrier, TextMapGetter<C> getter) Extracts data from upstream.fields()
The propagation fields defined.<C> void
inject
(Context context, C carrier, TextMapSetter<C> setter) Injects data for downstream consumers, for example as HTTP headers.toString()
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Field Details
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EXTRACTED_KEY_VALUES
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fields
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Constructor Details
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PassThroughPropagator
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Method Details
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create
Returns aTextMapPropagator
which will propagate the givenfields
from extraction to injection. -
create
Returns aTextMapPropagator
which will propagate the givenfields
from extraction to injection. -
fields
Description copied from interface:TextMapPropagator
The propagation fields defined. If your carrier is reused, you should delete the fields here before callingTextMapPropagator.inject(Context, Object, TextMapSetter)
)}.For example, if the carrier is a single-use or immutable request object, you don't need to clear fields as they couldn't have been set before. If it is a mutable, retryable object, successive calls should clear these fields first.
Some use cases for this are:
- Allow pre-allocation of fields, especially in systems like gRPC Metadata
- Allow a single-pass over an iterator
- Specified by:
fields
in interfaceTextMapPropagator
- Returns:
- the fields that will be used by this formatter.
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inject
Description copied from interface:TextMapPropagator
Injects data for downstream consumers, for example as HTTP headers. The carrier may be null to facilitate calling this method with a lambda for theTextMapSetter
, in which case that null will be passed to theTextMapSetter
implementation.- Specified by:
inject
in interfaceTextMapPropagator
- Type Parameters:
C
- carrier of propagation fields, such as an http request- Parameters:
context
- theContext
containing the value to be injected.carrier
- holds propagation fields. For example, an outgoing message or http request.setter
- invoked for each propagation key to add or remove.
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extract
Description copied from interface:TextMapPropagator
Extracts data from upstream. For example, from incoming http headers. The returned Context should contain the extracted data, if any, merged with the data from the passed-in Context.If the incoming information could not be parsed, implementations MUST return the original Context, unaltered.
- Specified by:
extract
in interfaceTextMapPropagator
- Type Parameters:
C
- the type of carrier of the propagation fields, such as an http request.- Parameters:
context
- theContext
used to store the extracted value.carrier
- holds propagation fields. For example, an outgoing message or http request.getter
- invoked for each propagation key to get data from the carrier.- Returns:
- the
Context
containing the extracted data.
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toString
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