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:
1telemetry:
2 instrumentation:
3 spans:
4 router:
5 attributes:
6 "my_attribute":
7 # ...
8 request_header: "x-my-header" #highlight-lineSelector 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 performance) | |
response_errors | Yes | JSON Path into the supergraph response body errors (it might impact performance) | |
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_name | No | true|false | The subgraph name |
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 |
cache | No | hit|miss | Returns the number of cache hit or miss for this subgraph request |
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 |