feat(plugin)!: Add Switchyard Decision API routing plugin

.gitignore

@@ -85,3 +85,4 @@ CHANGELOG.md
 
 # Relay
 /.nemo-relay
+/artifacts/

ATTRIBUTIONS-Rust.md

@@ -37612,6 +37612,87 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ```
 
+## switchyard-translation - 0.1.0
+**Repository URL**: https://github.com/NVIDIA-NeMo/Switchyard
+**License Type(s)**: Apache-2.0
+### License: https://spdx.org/licenses/Apache-2.0.html
+```
+Apache License
+Version 2.0, January 2004
+http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
+
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+
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+
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+
+"You" (or "Your") shall mean an individual or Legal Entity exercising permissions granted by this License.
+
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+
+"Work" shall mean the work of authorship, whether in Source or Object form, made available under the License, as indicated by a copyright notice that is included in or attached to the work (an example is provided in the Appendix below).
+
+"Derivative Works" shall mean any work, whether in Source or Object form, that is based on (or derived from) the Work and for which the editorial revisions, annotations, elaborations, or other modifications represent, as a whole, an original work of authorship. For the purposes of this License, Derivative Works shall not include works that remain separable from, or merely link (or bind by name) to the interfaces of, the Work and Derivative Works thereof.
+
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+
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+
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+
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+
+9. Accepting Warranty or Additional Liability. While redistributing the Work or Derivative Works thereof, You may choose to offer, and charge a fee for, acceptance of support, warranty, indemnity, or other liability obligations and/or rights consistent with this License. However, in accepting such obligations, You may act only on Your own behalf and on Your sole responsibility, not on behalf of any other Contributor, and only if You agree to indemnify, defend, and hold each Contributor harmless for any liability incurred by, or claims asserted against, such Contributor by reason of your accepting any such warranty or additional liability.
+
+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
+
+To apply the Apache License to your work, attach the following boilerplate notice, with the fields enclosed by brackets "[]" replaced with your own identifying information. (Don't include the brackets!)  The text should be enclosed in the appropriate comment syntax for the file format. We also recommend that a file or class name and description of purpose be included on the same "printed page" as the copyright notice for easier identification within third-party archives.
+
+Copyright [yyyy] [name of copyright owner]
+
+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
+
+http://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.
+
+```
+
 ## syn - 2.0.117
 **Repository URL**: https://github.com/dtolnay/syn
 **License Type(s)**: Apache-2.0

Cargo.toml

@@ -10,6 +10,7 @@ members = [
     "crates/worker",
     "crates/adaptive",
     "crates/pii-redaction",
+    "crates/switchyard",
     "crates/cli",
     # Language Bindings
     "crates/python",
@@ -33,6 +34,8 @@ nemo-relay-worker-proto = { version = "0.6.0", path = "crates/worker-proto" }
 nemo-relay-worker = { version = "0.6.0", path = "crates/worker" }
 nemo-relay-adaptive = { version = "0.6.0", path = "crates/adaptive" }
 nemo-relay-pii-redaction = { version = "0.6.0", path = "crates/pii-redaction" }
+nemo-relay-switchyard = { version = "0.6.0", path = "crates/switchyard" }
+switchyard-translation = { git = "https://github.com/NVIDIA-NeMo/Switchyard.git", rev = "8f9db9a6a47f848cdff1d262276ba25a8ae9cbc8" }
 nemo-relay-ffi = { version = "0.6.0", path = "crates/ffi" }
 nemo-relay-cli = { version = "0.6.0", path = "crates/cli" }
 opentelemetry = { version = "0.31", default-features = false }

crates/cli/Cargo.toml

@@ -23,11 +23,13 @@ workspace = true
 [features]
 default = ["atof-streaming"]
 atof-streaming = ["nemo-relay/atof-streaming"]
+switchyard = ["dep:nemo-relay-switchyard"]
 
 [dependencies]
 nemo-relay = { workspace = true, features = ["guardrails-remote", "object-store", "otel", "openinference", "worker-grpc"] }
 nemo-relay-adaptive = { workspace = true, features = ["redis-backend"] }
 nemo-relay-pii-redaction.workspace = true
+nemo-relay-switchyard = { workspace = true, optional = true, features = ["schema"] }
 async-stream = "0.3"
 axum = "0.8"
 base64 = "0.22"
@@ -61,3 +63,8 @@ opentelemetry = { workspace = true, features = ["trace"] }
 opentelemetry_sdk = { workspace = true, features = ["trace", "testing"] }
 tempfile = "3"
 tower = { version = "0.5", features = ["util"] }
+
+[[test]]
+name = "switchyard_process_e2e"
+path = "tests/switchyard_process_e2e.rs"
+required-features = ["switchyard"]

crates/cli/src/doctor.rs

@@ -20,6 +20,10 @@ use nemo_relay::observability::plugin_component::OBSERVABILITY_PLUGIN_KIND;
 use nemo_relay::plugin::{DiagnosticLevel, PluginConfig, validate_plugin_config};
 use nemo_relay_adaptive::plugin_component::register_adaptive_component;
 use nemo_relay_pii_redaction::component::register_pii_redaction_component;
+#[cfg(feature = "switchyard")]
+use nemo_relay_switchyard::{
+    register_switchyard_component, validate_switchyard_atof_configuration,
+};
 use serde::Serialize;
 use serde_json::{Value, json};
 use tokio::time::timeout;
@@ -678,6 +682,24 @@ async fn collect_observability(gateway: &GatewayConfig) -> Vec<Check> {
         });
         return checks;
     }
+    #[cfg(feature = "switchyard")]
+    if let Err(error) = register_switchyard_component() {
+        checks.push(Check {
+            name: "Switchyard plugin",
+            status: Status::Fail,
+            details: format!("registration failed: {error}"),
+        });
+        return checks;
+    }
+    #[cfg(feature = "switchyard")]
+    if let Err(error) = validate_switchyard_atof_configuration(&plugin_config) {
+        checks.push(Check {
+            name: "Switchyard ATOF",
+            status: Status::Fail,
+            details: error,
+        });
+        return checks;
+    }
     let report = validate_plugin_config(&plugin_config);
     if report.diagnostics.is_empty() {
         checks.push(Check {
@@ -982,18 +1004,45 @@ async fn probe_atof_endpoint(index: usize, endpoint: &Value) -> Check {
 }
 
 fn endpoint_headers(endpoint: &Value) -> Result<Vec<(String, String)>, String> {
-    let Some(headers) = endpoint.get("headers") else {
-        return Ok(Vec::new());
-    };
-    let Some(object) = headers.as_object() else {
-        return Err("headers must be an object of string values".into());
-    };
-    let mut out = Vec::with_capacity(object.len());
-    for (key, value) in object {
-        let Some(value) = value.as_str() else {
-            return Err(format!("headers.{key} must be a string"));
+    let mut out = Vec::new();
+    let mut names = std::collections::HashSet::new();
+    if let Some(headers) = endpoint.get("headers") {
+        let Some(object) = headers.as_object() else {
+            return Err("headers must be an object of string values".into());
+        };
+        for (key, value) in object {
+            let name = reqwest::header::HeaderName::from_bytes(key.as_bytes())
+                .map_err(|error| error.to_string())?;
+            let Some(value) = value.as_str() else {
+                return Err(format!("headers.{key} must be a string"));
+            };
+            names.insert(name);
+            out.push((key.clone(), value.to_string()));
+        }
+    }
+    if let Some(header_env) = endpoint.get("header_env") {
+        let Some(object) = header_env.as_object() else {
+            return Err("header_env must be an object of string values".into());
         };
-        out.push((key.clone(), value.to_string()));
+        for (key, variable) in object {
+            let name = reqwest::header::HeaderName::from_bytes(key.as_bytes())
+                .map_err(|error| error.to_string())?;
+            if names.contains(&name) {
+                return Err(format!(
+                    "header {key:?} cannot appear in both headers and header_env"
+                ));
+            }
+            let Some(variable) = variable.as_str() else {
+                return Err(format!("header_env.{key} must be a string"));
+            };
+            let value = std::env::var(variable)
+                .map_err(|_| format!("environment variable {variable:?} is not set"))?;
+            if value.trim().is_empty() {
+                return Err(format!("environment variable {variable:?} is blank"));
+            }
+            names.insert(name);
+            out.push((key.clone(), value));
+        }
     }
     Ok(out)
 }

crates/cli/src/error.rs

@@ -4,7 +4,7 @@
 use axum::Json;
 use axum::http::StatusCode;
 use axum::response::{IntoResponse, Response};
-use nemo_relay::error::FlowError;
+use nemo_relay::error::{FlowError, UpstreamFailure};
 use serde::Serialize;
 use serde_json::{Map, Value, json};
 use strum::Display;
@@ -36,6 +36,8 @@ pub(crate) enum CliError {
     PayloadTooLarge(String),
     #[error("gateway upstream error: {0}")]
     Upstream(#[from] reqwest::Error),
+    #[error("{0}")]
+    ProviderFailure(UpstreamFailure),
     #[error("http error: {0}")]
     Http(#[from] http::Error),
     #[error("io error: {0}")]
@@ -87,16 +89,21 @@ impl CliError {
 
 impl IntoResponse for CliError {
     // Maps gateway errors into a compact JSON HTTP response. Bad hook payloads are client errors,
-    // upstream gateway failures are bad gateway responses, and local install/config/runtime faults
-    // remain internal errors so callers do not mistake them for agent policy decisions.
+    // network-level upstream failures are bad gateway responses, provider failures mirror the
+    // upstream status when available, and local install/config/runtime faults remain internal
+    // errors so callers do not mistake them for agent policy decisions.
     fn into_response(self) -> Response {
         let message = self.to_string();
         let guardrail_reason = self.guardrail_rejection_reason().map(ToOwned::to_owned);
-        let status = match (guardrail_reason.is_some(), self) {
+        let status = match (guardrail_reason.is_some(), &self) {
             (true, _) => StatusCode::FORBIDDEN,
             (false, Self::PayloadTooLarge(_)) => StatusCode::PAYLOAD_TOO_LARGE,
             (false, Self::InvalidPayload(_)) => StatusCode::BAD_REQUEST,
             (false, Self::Upstream(_)) => StatusCode::BAD_GATEWAY,
+            (false, Self::ProviderFailure(failure)) => failure
+                .status
+                .and_then(|status| StatusCode::from_u16(status).ok())
+                .unwrap_or(StatusCode::BAD_GATEWAY),
             (
                 false,
                 Self::Http(_)