Telemetry instrumentation config for http_client headers

.changesets/config_http_client_header_telemetry.md

@@ -0,0 +1,20 @@
+### Telemetry instrumentation config for http_client headers ([PR #8349](https://github.com/apollographql/router/pull/8349))
+
+Adds a new telemetry instrumentation configuration for the http_client spans. This setting allows request headers added by Rhai scripts to be attached to the http_client span. The `some_rhai_response_header` value is available on the subgraph span as before.
+
+```yaml
+telemetry:
+  instrumentation:
+    spans:
+      mode: spec_compliant
+      subgraph:
+        attributes:
+          http.response.header.some_rhai_response_header:
+            subgraph_response_header: "some_rhai_response_header"
+      http_client:
+        attributes:
+          http.request.header.some_rhai_request_header:
+            request_header: "some_rhai_request_header"
+```
+
+By [@bonnici](https://github.com/bonnici) in https://github.com/apollographql/router/pull/8349

apollo-router/src/configuration/snapshots/apollo_router__configuration__tests__schema_generation.snap

@@ -1157,6 +1157,133 @@ expression: "&schema"
         }
       ]
     },
+    "ConditionHttpClientSelector": {
+      "description": "Specify a condition for when an [instrument][] should be mutated or an [event][] should be triggered.\n\n[instrument]: https://www.apollographql.com/docs/graphos/routing/observability/telemetry/instrumentation/instruments\n[event]: https://www.apollographql.com/docs/graphos/routing/observability/telemetry/instrumentation/events",
+      "oneOf": [
+        {
+          "additionalProperties": false,
+          "description": "A condition to check a selection against a value.",
+          "properties": {
+            "eq": {
+              "items": {
+                "$ref": "#/definitions/HttpClientSelectorOrValue"
+              },
+              "maxItems": 2,
+              "minItems": 2,
+              "type": "array"
+            }
+          },
+          "required": [
+            "eq"
+          ],
+          "type": "object"
+        },
+        {
+          "additionalProperties": false,
+          "description": "The first selection must be greater than the second selection.",
+          "properties": {
+            "gt": {
+              "items": {
+                "$ref": "#/definitions/HttpClientSelectorOrValue"
+              },
+              "maxItems": 2,
+              "minItems": 2,
+              "type": "array"
+            }
+          },
+          "required": [
+            "gt"
+          ],
+          "type": "object"
+        },
+        {
+          "additionalProperties": false,
+          "description": "The first selection must be less than the second selection.",
+          "properties": {
+            "lt": {
+              "items": {
+                "$ref": "#/definitions/HttpClientSelectorOrValue"
+              },
+              "maxItems": 2,
+              "minItems": 2,
+              "type": "array"
+            }
+          },
+          "required": [
+            "lt"
+          ],
+          "type": "object"
+        },
+        {
+          "additionalProperties": false,
+          "description": "A condition to check a selection against a selector.",
+          "properties": {
+            "exists": {
+              "$ref": "#/definitions/HttpClientSelector"
+            }
+          },
+          "required": [
+            "exists"
+          ],
+          "type": "object"
+        },
+        {
+          "additionalProperties": false,
+          "description": "All sub-conditions must be true.",
+          "properties": {
+            "all": {
+              "items": {
+                "$ref": "#/definitions/ConditionHttpClientSelector"
+              },
+              "type": "array"
+            }
+          },
+          "required": [
+            "all"
+          ],
+          "type": "object"
+        },
+        {
+          "additionalProperties": false,
+          "description": "At least one sub-conditions must be true.",
+          "properties": {
+            "any": {
+              "items": {
+                "$ref": "#/definitions/ConditionHttpClientSelector"
+              },
+              "type": "array"
+            }
+          },
+          "required": [
+            "any"
+          ],
+          "type": "object"
+        },
+        {
+          "additionalProperties": false,
+          "description": "The sub-condition must not be true",
+          "properties": {
+            "not": {
+              "$ref": "#/definitions/ConditionHttpClientSelector"
+            }
+          },
+          "required": [
+            "not"
+          ],
+          "type": "object"
+        },
+        {
+          "const": "true",
+          "description": "Static true condition",
+          "type": "string"
+        },
+        {
+          "const": "false",
+          "description": "Static false condition",
+          "type": "string"
+        }
+      ]
+    },
     "ConditionRouterSelector": {
       "description": "Specify a condition for when an [instrument][] should be mutated or an [event][] should be triggered.\n\n[instrument]: https://www.apollographql.com/docs/graphos/routing/observability/telemetry/instrumentation/instruments\n[event]: https://www.apollographql.com/docs/graphos/routing/observability/telemetry/instrumentation/events",
       "oneOf": [
@@ -1553,6 +1680,21 @@ expression: "&schema"
         }
       ]
     },
+    "ConditionalHttpClientSelector": {
+      "anyOf": [
+        {
+          "$ref": "#/definitions/HttpClientSelector"
+        },
+        {
+          "properties": {
+            "condition": {
+              "$ref": "#/definitions/ConditionHttpClientSelector"
+            }
+          },
+          "type": "object"
+        }
+      ]
+    },
     "ConditionalRouterSelector": {
       "anyOf": [
         {
@@ -3751,6 +3893,12 @@ expression: "&schema"
       },
       "type": "object"
     },
+    "ExtendedHttpClientAttributesWithConditionalHttpClientSelector": {
+      "additionalProperties": {
+        "$ref": "#/definitions/ConditionalHttpClientSelector"
+      },
+      "type": "object"
+    },
     "ExtendedRouterAttributesWithConditionalRouterSelector": {
       "additionalProperties": {
         "$ref": "#/definitions/ConditionalRouterSelector"
@@ -5280,6 +5428,86 @@ expression: "&schema"
         }
       ]
     },
+    "HttpClientSelector": {
+      "anyOf": [
+        {
+          "additionalProperties": false,
+          "description": "A header from the HTTP request",
+          "properties": {
+            "default": {
+              "description": "Optional default value.",
+              "type": [
+                "string",
+                "null"
+              ]
+            },
+            "request_header": {
+              "description": "The name of the request header.",
+              "type": "string"
+            }
+          },
+          "required": [
+            "request_header"
+          ],
+          "type": "object"
+        },
+        {
+          "additionalProperties": false,
+          "description": "A header from the HTTP response",
+          "properties": {
+            "default": {
+              "description": "Optional default value.",
+              "type": [
+                "string",
+                "null"
+              ]
+            },
+            "response_header": {
+              "description": "The name of the response header.",
+              "type": "string"
+            }
+          },
+          "required": [
+            "response_header"
+          ],
+          "type": "object"
+        }
+      ]
+    },
+    "HttpClientSelectorOrValue": {
+      "anyOf": [
+        {
+          "allOf": [
+            {
+              "$ref": "#/definitions/AttributeValue"
+            }
+          ],
+          "description": "A constant value."
+        },
+        {
+          "allOf": [
+            {
+              "$ref": "#/definitions/HttpClientSelector"
+            }
+          ],
+          "description": "Selector to extract a value from the pipeline."
+        }
+      ]
+    },
+    "HttpClientSpans": {
+      "additionalProperties": false,
+      "properties": {
+        "attributes": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/ExtendedHttpClientAttributesWithConditionalHttpClientSelector"
+            }
+          ],
+          "description": "Custom attributes that are attached to the HTTP client span."
+        }
+      },
+      "type": "object"
+    },
     "HttpExporter": {
       "additionalProperties": false,
       "properties": {
@@ -8279,6 +8507,14 @@ expression: "&schema"
           ],
           "description": "The attributes to include by default in spans based on their level as specified in the otel semantic conventions and Apollo documentation."
         },
+        "http_client": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/HttpClientSpans"
+            }
+          ],
+          "description": "Attributes to include on the HTTP client span.\nHTTP client spans contain information about HTTP requests made to subgraphs, including any changes made by Rhai scripts."
+        },
         "mode": {
           "allOf": [
             {

apollo-router/src/plugins/telemetry/config_new/http_client/attributes.rs

@@ -0,0 +1,41 @@
+use std::fmt::Debug;
+
+use opentelemetry::KeyValue;
+use schemars::JsonSchema;
+use serde::Deserialize;
+use tower::BoxError;
+
+use crate::Context;
+use crate::plugins::telemetry::config_new::DefaultForLevel;
+use crate::plugins::telemetry::config_new::Selectors;
+use crate::plugins::telemetry::config_new::attributes::DefaultAttributeRequirementLevel;
+use crate::plugins::telemetry::otlp::TelemetryDataKind;
+use crate::services::http;
+
+#[derive(Deserialize, JsonSchema, Clone, Default, Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+#[serde(deny_unknown_fields, default)]
+pub(crate) struct HttpClientAttributes {}
+
+impl DefaultForLevel for HttpClientAttributes {
+    fn defaults_for_level(
+        &mut self,
+        _requirement_level: DefaultAttributeRequirementLevel,
+        _kind: TelemetryDataKind,
+    ) {
+    }
+}
+
+impl Selectors<http::HttpRequest, http::HttpResponse, ()> for HttpClientAttributes {
+    fn on_request(&self, _request: &http::HttpRequest) -> Vec<KeyValue> {
+        Vec::new()
+    }
+
+    fn on_response(&self, _response: &http::HttpResponse) -> Vec<KeyValue> {
+        Vec::new()
+    }
+
+    fn on_error(&self, _error: &BoxError, _ctx: &Context) -> Vec<KeyValue> {
+        Vec::new()
+    }
+}

apollo-router/src/plugins/telemetry/config_new/http_client/mod.rs

@@ -0,0 +1,3 @@
+pub(crate) mod attributes;
+pub(crate) mod selectors;
+pub(crate) mod spans;