impl(gax-internal): HttpSpanInfo struct, new, and update_from_outcome (#3352)

westarle · web-flow · commit b128db3ba6ca · 2025-09-18T12:03:33.000-04:00
diff --git a/src/gax-internal/src/lib.rs b/src/gax-internal/src/lib.rs
@@ -36,6 +36,9 @@ pub mod query_parameter;
 #[cfg(feature = "_internal-http-client")]
 pub mod http;
 
+#[cfg(feature = "_internal-http-client")]
+pub mod observability;
+
 #[cfg(feature = "_internal-grpc-client")]
 pub mod grpc;
 
diff --git a/src/gax-internal/src/observability.rs b/src/gax-internal/src/observability.rs
@@ -0,0 +1,319 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![allow(dead_code)] // TODO(#3239): Remove once used in http.rs
+
+use crate::options::InstrumentationClientInfo;
+use gax::options::RequestOptions;
+
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) enum OtelStatus {
+    Unset,
+    Ok,
+    Error,
+}
+
+impl OtelStatus {
+    pub(crate) fn as_str(&self) -> &'static str {
+        match self {
+            OtelStatus::Unset => "Unset",
+            OtelStatus::Ok => "Ok",
+            OtelStatus::Error => "Error",
+        }
+    }
+}
+
+/// Populate attributes of tracing spans for HTTP requests.
+///
+/// OpenTelemetry recommends a number of semantic conventions for
+/// tracing HTTP requests. This type holds the information extracted
+/// from HTTP requests and responses, formatted to align with these
+/// OpenTelemetry semantic conventions.
+/// See [OpenTelemetry Semantic Conventions for HTTP](https://opentelemetry.io/docs/specs/semconv/http/http-spans/).
+#[derive(Debug, Clone)]
+pub(crate) struct HttpSpanInfo {
+    // Attributes for OpenTelemetry SDK interop
+    /// Span Kind. Always CLIENT for a span representing an outbound HTTP request.
+    otel_kind: String,
+    /// Span Name. Recommended to be "{http.request.method} {url.template}" if url.template is available, otherwise "{http.request.method}".
+    otel_name: String,
+    /// Span Status. Set to Error in the event of an unrecoverable error, for example network error, 5xx status codes. Unset otherwise (including 4xx codes for CLIENT spans).
+    otel_status: OtelStatus,
+
+    // OpenTelemetry Semantic Conventions
+    /// Which RPC system is being used. Set to "http" for REST calls.
+    rpc_system: String,
+    /// The HTTP request method, for example GET; POST; HEAD.
+    http_request_method: String,
+    /// The actual destination host name or IP address. May differ from the URL's host if overridden, for example myservice.googleapis.com; myservice-staging.sandbox.googleapis.com; 10.0.0.1.
+    server_address: String,
+    /// The actual destination port number. May differ from the URL's port if overridden, for example 443; 8080.
+    server_port: i64,
+    /// The absolute URL of the request, for example https://www.foo.bar/search?q=OpenTelemetry.
+    url_full: String,
+    /// The URI scheme component identifying the used protocol, for example http; https.
+    url_scheme: Option<String>,
+    /// The low-cardinality template of the absolute path, for example /v2/locations/{location}/projects/{project}/.
+    url_template: Option<String>,
+    /// The nominal domain from the original URL, representing the intended service, for example myservice.googleapis.com.
+    url_domain: Option<String>,
+
+    /// The numeric HTTP response status code, for example 200; 404; 500.
+    http_response_status_code: Option<i64>,
+    /// A low cardinality a class of error the operation ended with.
+    /// For HTTP status codes >= 400, this is the status code as a string.
+    /// For network errors, a short identifier like TIMEOUT, CONNECTION_ERROR.
+    error_type: Option<String>,
+    /// The ordinal number of times this request has been resent (e.g., due to retries or redirects). None for the first attempt.
+    http_request_resend_count: Option<i64>,
+
+    // Custom GCP Attributes
+    /// Identifies the Google Cloud service, for example appengine; run; firestore.
+    gcp_client_service: Option<String>,
+    /// The version of the client library, for example v1.0.2.
+    gcp_client_version: Option<String>,
+    /// The repository of the client library. Always "googleapis/google-cloud-rust".
+    gcp_client_repo: String,
+    /// The crate name of the client library, for example google-cloud-storage.
+    gcp_client_artifact: Option<String>,
+}
+
+impl HttpSpanInfo {
+    pub(crate) fn from_request(
+        request: &reqwest::Request,
+        options: &RequestOptions,
+        instrumentation: Option<&InstrumentationClientInfo>,
+        prior_attempt_count: u32,
+    ) -> Self {
+        let url = request.url();
+        let method = request.method();
+
+        let url_template = gax::options::internal::get_path_template(options);
+        let otel_name = url_template.map_or_else(
+            || method.to_string(),
+            |template| format!("{} {}", method, template),
+        );
+
+        let http_request_resend_count = if prior_attempt_count > 0 {
+            Some(prior_attempt_count as i64)
+        } else {
+            None
+        };
+
+        let (gcp_client_service, gcp_client_version, gcp_client_artifact, url_domain) =
+            instrumentation.map_or((None, None, None, None), |info| {
+                (
+                    Some(info.service_name.to_string()),
+                    Some(info.client_version.to_string()),
+                    Some(info.client_artifact.to_string()),
+                    Some(info.default_host.to_string()),
+                )
+            });
+
+        Self {
+            rpc_system: "http".to_string(),
+            otel_kind: "Client".to_string(),
+            otel_name,
+            otel_status: OtelStatus::Unset,
+            http_request_method: method.to_string(),
+            server_address: url.host_str().map(String::from).unwrap_or_default(),
+            server_port: url.port_or_known_default().map(|p| p as i64).unwrap_or(0),
+            url_full: url.to_string(),
+            url_scheme: Some(url.scheme().to_string()),
+            url_template: url_template.map(String::from),
+            url_domain,
+            http_response_status_code: None,
+            error_type: None,
+            http_request_resend_count,
+            gcp_client_service,
+            gcp_client_version,
+            gcp_client_repo: "googleapis/google-cloud-rust".to_string(),
+            gcp_client_artifact,
+        }
+    }
+
+    /// Updates the span info based on the outcome of the HTTP request.
+    ///
+    /// This method should be called after the request has completed, it will fill in any parts of
+    /// the span that depend on the result of the request.
+    pub(crate) fn update_from_response(
+        &mut self,
+        result: &Result<reqwest::Response, reqwest::Error>,
+    ) {
+        match result {
+            Ok(response) => {
+                self.http_response_status_code = Some(response.status().as_u16() as i64);
+                if response.status().is_success() {
+                    self.otel_status = OtelStatus::Ok;
+                } else {
+                    self.otel_status = OtelStatus::Error;
+                    self.error_type = Some(response.status().to_string());
+                }
+            }
+            Err(err) => {
+                self.otel_status = OtelStatus::Error;
+                if err.is_timeout() {
+                    self.error_type = Some("TIMEOUT".to_string());
+                } else if err.is_connect() {
+                    self.error_type = Some("CONNECTION_ERROR".to_string());
+                } else if err.is_request() {
+                    self.error_type = Some("REQUEST_ERROR".to_string());
+                } else {
+                    self.error_type = Some("UNKNOWN".to_string());
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::options::InstrumentationClientInfo;
+    use gax::options::RequestOptions;
+    use http::Method;
+    use reqwest;
+
+    #[tokio::test]
+    async fn test_http_span_info_from_request_basic() {
+        let request =
+            reqwest::Request::new(Method::GET, "https://example.com/test".parse().unwrap());
+        let options = RequestOptions::default();
+
+        let span_info = HttpSpanInfo::from_request(&request, &options, None, 0);
+
+        assert_eq!(span_info.rpc_system, "http");
+        assert_eq!(span_info.otel_kind, "Client");
+        assert_eq!(span_info.otel_name, "GET");
+        assert_eq!(span_info.otel_status, OtelStatus::Unset);
+        assert_eq!(span_info.http_request_method, "GET");
+        assert_eq!(span_info.server_address, "example.com".to_string());
+        assert_eq!(span_info.server_port, 443);
+        assert_eq!(span_info.url_full, "https://example.com/test");
+        assert_eq!(span_info.url_scheme, Some("https".to_string()));
+        assert_eq!(span_info.url_template, None);
+        assert_eq!(span_info.url_domain, None);
+        assert_eq!(span_info.http_response_status_code, None);
+        assert_eq!(span_info.error_type, None);
+        assert_eq!(span_info.http_request_resend_count, None);
+        assert_eq!(span_info.gcp_client_service, None);
+        assert_eq!(span_info.gcp_client_version, None);
+        assert_eq!(span_info.gcp_client_repo, "googleapis/google-cloud-rust");
+        assert_eq!(span_info.gcp_client_artifact, None);
+    }
+
+    #[tokio::test]
+    async fn test_http_span_info_from_request_with_instrumentation() {
+        let request = reqwest::Request::new(
+            Method::POST,
+            "https://test.service.dev:443/v1/items".parse().unwrap(),
+        );
+        let options = RequestOptions::default();
+        const INFO: InstrumentationClientInfo = InstrumentationClientInfo {
+            service_name: "test.service",
+            client_version: "1.2.3",
+            client_artifact: "google-cloud-test",
+            default_host: "test.service.dev",
+        };
+
+        let span_info = HttpSpanInfo::from_request(&request, &options, Some(&INFO), 0);
+
+        assert_eq!(
+            span_info.gcp_client_service,
+            Some("test.service".to_string())
+        );
+        assert_eq!(span_info.gcp_client_version, Some("1.2.3".to_string()));
+        assert_eq!(
+            span_info.gcp_client_artifact,
+            Some("google-cloud-test".to_string())
+        );
+        assert_eq!(span_info.url_domain, Some("test.service.dev".to_string()));
+        assert_eq!(span_info.server_address, "test.service.dev".to_string());
+        assert_eq!(span_info.server_port, 443);
+    }
+
+    #[tokio::test]
+    async fn test_http_span_info_from_request_with_path_template() {
+        let request = reqwest::Request::new(
+            Method::GET,
+            "https://example.com/items/123".parse().unwrap(),
+        );
+        let options = gax::options::internal::set_path_template(
+            RequestOptions::default(),
+            Some("/items/{item_id}".to_string()),
+        );
+
+        let span_info = HttpSpanInfo::from_request(&request, &options, None, 0);
+
+        assert_eq!(span_info.url_template, Some("/items/{item_id}".to_string()));
+        assert_eq!(span_info.otel_name, "GET /items/{item_id}");
+    }
+
+    #[tokio::test]
+    async fn test_http_span_info_from_request_with_prior_attempt_count() {
+        let request =
+            reqwest::Request::new(Method::GET, "https://example.com/test".parse().unwrap());
+        let options = RequestOptions::default();
+
+        // prior_attempt_count is 0 for the first try
+        let span_info = HttpSpanInfo::from_request(&request, &options, None, 0);
+        assert_eq!(span_info.http_request_resend_count, None);
+
+        // prior_attempt_count is 1 for the second try (first retry)
+        let span_info = HttpSpanInfo::from_request(&request, &options, None, 1);
+        assert_eq!(span_info.http_request_resend_count, Some(1));
+
+        let span_info = HttpSpanInfo::from_request(&request, &options, None, 5);
+        assert_eq!(span_info.http_request_resend_count, Some(5));
+    }
+
+    #[tokio::test]
+    async fn test_update_from_response_success() {
+        let request =
+            reqwest::Request::new(Method::GET, "https://example.com/test".parse().unwrap());
+        let mut span_info =
+            HttpSpanInfo::from_request(&request, &RequestOptions::default(), None, 0);
+
+        let response =
+            reqwest::Response::from(http::Response::builder().status(200).body("").unwrap());
+        span_info.update_from_response(&Ok(response));
+
+        assert_eq!(span_info.otel_status, OtelStatus::Ok);
+        assert_eq!(span_info.http_response_status_code, Some(200));
+        assert_eq!(span_info.error_type, None);
+    }
+
+    #[tokio::test]
+    async fn test_update_from_response_http_error() {
+        let request =
+            reqwest::Request::new(Method::GET, "https://example.com/test".parse().unwrap());
+        let mut span_info =
+            HttpSpanInfo::from_request(&request, &RequestOptions::default(), None, 0);
+
+        let response =
+            reqwest::Response::from(http::Response::builder().status(404).body("").unwrap());
+        span_info.update_from_response(&Ok(response));
+
+        assert_eq!(span_info.otel_status, OtelStatus::Error);
+        assert_eq!(span_info.http_response_status_code, Some(404));
+        assert_eq!(span_info.error_type, Some("404 Not Found".to_string()));
+    }
+
+    #[test]
+    fn test_otel_status_as_str() {
+        assert_eq!(OtelStatus::Unset.as_str(), "Unset");
+        assert_eq!(OtelStatus::Ok.as_str(), "Ok");
+        assert_eq!(OtelStatus::Error.as_str(), "Error");
+    }
+}
