Selectors

Select data from the router pipeline to extract

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

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

router.yaml

1
telemetry:
2
  instrumentation:
3
    spans:
4
      router:
5
        attributes:
6
          "my_attribute":
7
            # ...
8
            request_header: "x-my-header"

Selector configuration reference

Each service of the router pipeline (router, supergraph, subgraph) has its own available selectors. You can also extract GraphQL metrics from the response data the router returns to clients.

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
`operation_name`	Yes	`string`\|`hash`	The operation name from the query
`studio_operation_id`	Yes	`true`\|`false`	The Apollo Studio operation 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
`on_graphql_error`	No	`true`\|`false`	Boolean set to true if the response payload contains a graphql error
`static`	No		A static string value
`error`	No	`reason`	a string value containing error reason when it's a critical error

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	`string`\|`hash`	The operation name from the query
`operation_kind`	No	`string`	The operation kind from the query
`query`	Yes	`string`\|`aliases`\|`depth`\|`height`\|`root_fields`	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
`is_primary_response`	No	`true`\|`false`	Boolean returning true if it's the primary response and not events like subscription events or deferred responses
`response_data`	Yes		Json Path into the supergraph response body data (it might impact performances)
`response_errors`	Yes		Json Path into the supergraph response body errors (it might impact performances)
`request_context`	Yes		The name of a request context key
`response_context`	Yes		The name of a response context key
`on_graphql_error`	No	`true`\|`false`	Boolean set to true if the response payload contains a graphql error
`baggage`	Yes		The name of a baggage item
`env`	Yes		The name of an environment variable
`static`	No		A static string value
`error`	No	`reason`	a string value containing error reason when it's a critical error

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	`string`\|`hash`	The operation name from the subgraph query
`subgraph_operation_kind`	No	`string`	The operation kind from the subgraph query
`subgraph_query`	Yes	`string`	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 performance)
`subgraph_response_errors`	Yes		Json Path into the subgraph response body errors (it might impact performance)
`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	`code`\|`reason`	The status of a subgraph response
`subgraph_on_graphql_error`	No	`true`\|`false`	Boolean set to true if the subgraph response payload contains a graphql error
`supergraph_operation_name`	Yes	`string`\|`hash`	The operation name from the supergraph query
`supergraph_operation_kind`	Yes	`string`	The operation kind from the supergraph query
`supergraph_query`	Yes	`string`	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
`static`	No		A static string value
`error`	No	`reason`	a string value containing error reason when it's a critical error

GraphQL

GraphQL metrics are extracted from the response data the router returns to client requests.

Selector	Defaultable	Values	Description
`list_length`	No	`value`	The length of a list from the response data
`field_name`	No	`string`	The name of a field from the response data
`field_type`	No	`string`	The type of a field from the response data
`type_name`	No		The GraphQL type from the response data
`operation_name`	Yes	`string`\|`hash`	The operation name of the query
`static`	No		A static string value

Spans

Standard Attributes