Spans

A span captures contextual information about requests and responses as they're processed through the router's request lifecycle (pipeline). The information from spans can be used when displaying traces in your application performance monitors (APM).

Spans configuration

Router request lifecycle services

The Apollo Router's request lifecycle has three major services:

• Router service - Handles an incoming request before it is parsed. Works within a context of opaque bytes.
• Supergraph service - Handles a request after it has been parsed and before it is sent to the subgraph. Works within a GraphQL context.
• Subgraph service - Handles a request after it has been sent to the subgraph. Works within a GraphQL context.

The router, supergraph and subgraph sections are used to define custom span configuration for each service:

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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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          # ...     
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      supergraph: 
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        attributes: {}
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          # ...
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      subgraph: 
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        attributes: {}
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          # ...

attributes

Spans may have attributes attached to them from the Apollo Router pipeline. These attributes are used to filter and group spans in your APM.

Attributes may be drawn from standard attributes or selectors.

The attributes that are available depend on the service of the pipeline.

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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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          # Standard attributes
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          http.response.status_code: true
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          # Custom attributes
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          "my_attribute":
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            response_header: "x-my-header"

default_attribute_requirement_level

The default_attribute_requirement_level option sets the default attributes to attach to spans, as defined by OpenTelemetry semantic conventions.

Valid values:

• required (default)
• recommended

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telemetry:
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  instrumentation:
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    spans:
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      # Set the default requirement level
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      default_attribute_requirement_level: required 

Attributes can be configured individually, so that required attributes can be overridden or disabled. For example, http.response.status_code is set individually to override the standard value:

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telemetry:
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  instrumentation:
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    spans:
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      # Set the default requirement level
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      default_attribute_requirement_level: required
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      router:
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        attributes:
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          # Disable standard attribute
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          http.response.status_code: false

mode

The mode option enables the router spans to either use legacy attributes in the router, or those defined in the OpenTelemetry specification.

Valid values:

• spec_compliant
• deprecated (default)

spec_compliant

This mode follows the OpenTelemetry spec. Attributes that were previously added to spans that did not follow conventions are now removed.

You will likely gain a significant performance improvement by using this mode as it reduces the number of attributes that are added to spans.

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telemetry:
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  instrumentation:
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    spans:
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      mode: spec_compliant

For now this is not the default, however it will be in a future release.

deprecated

This mode is the default and follows the previous behavior if you have not configured the mode option to spec_compliant.

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telemetry:
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  instrumentation:
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    spans:
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      mode: deprecated

Attributes are added to spans that do not follow OpenTelemetry conventions.

Span configuration example

An example configuration of telemetry.spans in router.yaml sets both standard and custom attributes for the router service:

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telemetry:
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  instrumentation:
3
    spans:
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      default_attribute_requirement_level: required
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      mode: spec_compliant
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      router:
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        attributes:
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          # Standard attributes (http)
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          dd.trace_id: false
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          http.request.body.size: false
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          http.response.body.size: false
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          http.request.method: false
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          # ...
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          # Custom attributes
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          "acme.custom_1":
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            trace_id: datadog
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          "acme.custom_2":
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            response_header: "X-CUSTOM2"
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            default: "unknown"
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          "acme.custom_3":
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            env: "ENV_VAR"
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          "static_attribute": "my_static_value"
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            # ...
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      supergraph:
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        attributes: {}
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          # ...
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      subgraph:
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        attributes: {}
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          # ...

Spans configuration reference