Selectors

Select data from the router pipeline to extract

A selector is used to extract data from the Apollo Router's request lifecycle (pipeline) services and attach them to telemetry, specifically spans, instruments, conditions.

Each service of the router pipeline (router, supergraph, subgraph) has its own available selectors.

An example of a selector, request_header, of the router service on a custom span attribute:

router.yaml

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telemetry:
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  instrumentation:
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    spans:
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      router:
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        attributes:
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          "my_attribute":
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            # ...
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            request_header: "x-my-header"

Selector configuration reference

Each service of the router pipeline (router, supergraph, subgraph) has its own available selectors.

Router

The router service is the initial entrypoint for all requests. It is HTTP centric and deals with opaque bytes.

Selector	Defaultable	Values	Description
`trace_id`	Yes	`open_telemetry`\|`datadog`	The trace ID
`request_header`	Yes		The name of the request header
`response_header`	Yes		The name of a response header
`response_status`	Yes	`code`\|`reason`	The response status
`response_context`	Yes		The name of a response context key
`baggage`	Yes		The name of a baggage item
`env`	Yes		The name of an environment variable

Supergraph

The supergraph service is executed after query parsing but before query execution. It is GraphQL centric and deals with GraphQL queries and responses.

Selector	Defaultable	Values	Description
`operation_name`	Yes		The operation name from the query
`operation_kind`	No	`string`	The operation kind from the query
`query`	Yes	`string`	The graphql query
`query_variable`	Yes		The name of a graphql query variable
`request_header`	Yes		The name of a request header
`response_header`	Yes		The name of a response header
`request_context`	Yes		The name of a request context key
`response_context`	Yes		The name of a response context key
`baggage`	Yes		The name of a baggage item
`env`	Yes		The name of an environment variable

Subgraph

The subgraph service executes multiple times during query execution, with each execution representing a call to a single subgraph. It is GraphQL centric and deals with GraphQL queries and responses.

Selector	Defaultable	Values	Description
`subgraph_operation_name`	Yes		The operation name from the subgraph query
`subgraph_operation_kind`	No	`string`	The operation kind from the subgraph query
`subgraph_query`	Yes		The graphql query to the subgraph
`subgraph_query_variable`	Yes		The name of a subgraph query variable
`subgraph_response_data`	Yes		Json Path into the subgraph response body data (it might impact performances)
`subgraph_response_errors`	Yes		Json Path into the subgraph response body errors (it might impact performances)
`subgraph_request_header`	Yes		The name of a subgraph request header
`subgraph_response_header`	Yes		The name of a subgraph response header
`subgraph_response_status`	Yes		The status of a subgraph response
`supergraph_operation_name`	Yes		The operation name from the supergraph query
`supergraph_operation_kind`	Yes	`string`	The operation kind from the supergraph query
`supergraph_query`	Yes		The graphql query to the supergraph
`supergraph_query_variable`	Yes		The name of a supergraph query variable
`request_context`	Yes		The name of a request context key
`response_context`	Yes		The name of a response context key
`baggage`	Yes		The name of a baggage item
`env`	Yes		The name of an environment variable

Spans

Standard attributes