#![expect(
clippy::clone_on_ref_ptr,
reason = "Arc::clone usage is intentional and ergonomic in this gateway dispatch path"
)]
mod finalize;
use std::sync::Arc;
use anyhow::{Result, anyhow};
use axum::body::Body;
use axum::response::Response;
use bytes::Bytes;
use systemprompt_ai::SafetyConfig;
use systemprompt_database::DbPool;
use systemprompt_identifiers::AiRequestId;
use systemprompt_models::profile::{GatewayConfig, ProviderRegistry};
use self::finalize::{FinalizeCtx, attach_request_id, finalize, run_request_safety_scan};
use super::audit::{GatewayAudit, GatewayRequestContext};
use super::policy::PolicyResolver;
use super::protocol::canonical::CanonicalRequest;
use super::protocol::inbound::InboundAdapter;
use super::protocol::outbound::OutboundCtx;
use super::quota;
use super::registry::GatewayUpstreamRegistry;
pub const REQUEST_ID_HEADER: &str = "x-systemprompt-request-id";
#[derive(Debug, Clone, Copy)]
pub struct GatewayService;
#[derive(Debug)]
pub struct DispatchInputs {
pub request: CanonicalRequest,
pub raw_body: Bytes,
pub ctx: GatewayRequestContext,
pub inbound: Arc<dyn InboundAdapter>,
}
#[derive(Debug, thiserror::Error)]
pub enum DispatchError {
#[error(transparent)]
PreAudit(anyhow::Error),
#[error(transparent)]
Recorded(anyhow::Error),
}
#[derive(Debug, thiserror::Error)]
#[error("{0}")]
pub struct PolicyDenied(pub String);
#[derive(Debug, thiserror::Error)]
#[error("{message}")]
pub struct QuotaExceeded {
pub message: String,
pub retry_after_seconds: i32,
}
#[derive(Debug, thiserror::Error)]
#[error("{message}")]
pub struct SafetyBlocked {
pub category: String,
pub message: String,
}
impl GatewayService {
pub async fn dispatch(
config: &GatewayConfig,
registry: &ProviderRegistry,
db: &DbPool,
inputs: DispatchInputs,
) -> Result<Response<Body>, DispatchError> {
let DispatchInputs {
request,
raw_body,
ctx,
inbound,
} = inputs;
if ctx.session_id.is_none() {
return Err(DispatchError::PreAudit(anyhow!(
"gateway dispatch missing conversation binding (session_id)"
)));
}
let ai_request_id = ctx.ai_request_id.clone();
if !config.is_model_exposed(registry, &request.model) {
tracing::warn!(
ai_request_id = %ai_request_id,
model = %request.model,
"Gateway denied: model not exposed by gateway policy or registry"
);
return Err(DispatchError::PreAudit(
PolicyDenied(format!(
"model '{}' is not permitted by gateway policy",
request.model
))
.into(),
));
}
let route = config
.resolve_route(registry, &request.model)
.ok_or_else(|| {
DispatchError::PreAudit(anyhow!(
"No gateway route matches model '{}'",
request.model
))
})?;
let provider = route.resolve(registry).ok_or_else(|| {
DispatchError::PreAudit(anyhow!(
"Gateway route '{}' provider '{}' is not declared in profile.providers",
route.id.as_str(),
route.provider.as_str()
))
})?;
let secrets = systemprompt_config::SecretsBootstrap::get()
.map_err(|e| DispatchError::PreAudit(anyhow!("Secrets not available: {e}")))?;
let upstream_api_key = secrets
.get(provider.api_key_secret.as_str())
.ok_or_else(|| {
DispatchError::PreAudit(anyhow!(
"Gateway API key secret '{}' not configured",
provider.api_key_secret.as_str()
))
})?;
let upstream = GatewayUpstreamRegistry::global()
.get(provider.wire.as_tag())
.ok_or_else(|| {
DispatchError::PreAudit(anyhow!(
"Gateway has no outbound adapter for wire protocol '{}'",
provider.wire.as_tag()
))
})?;
let is_streaming = request.stream;
tracing::info!(
ai_request_id = %ai_request_id,
user_id = %ctx.user_id,
model = %request.model,
provider = %route.provider,
upstream = %provider.endpoint,
wire_protocol = %ctx.wire_protocol,
streaming = is_streaming,
"Gateway request dispatched"
);
let resolver = PolicyResolver::new(db).map_err(DispatchError::PreAudit)?;
let policy = resolver.resolve().await;
let audit = Arc::new(
GatewayAudit::new(db, ctx.clone())
.map_err(|e| DispatchError::PreAudit(anyhow!("audit init failed: {e}")))?,
);
if let Err(e) = audit.open(&request, &raw_body).await {
tracing::error!(error = %e, "audit open failed — proceeding without audit row");
}
let reservation = quota::precheck_and_reserve(db, &ctx.user_id, &policy.quota_windows)
.await
.map_err(DispatchError::Recorded)?;
if let Some(decision) = reservation {
if !decision.allow {
let msg = format!(
"quota exceeded for window {}s (used {}/{:?})",
decision.window_seconds, decision.state.requests, decision.limit_requests
);
if let Err(e) = audit.fail(&msg).await {
tracing::warn!(error = %e, "quota audit fail failed");
}
return Err(DispatchError::Recorded(
QuotaExceeded {
message: msg,
retry_after_seconds: decision.window_seconds,
}
.into(),
));
}
}
enforce_request_safety(db, &ai_request_id, &request, &policy.safety, &audit).await?;
let upstream_model = route.effective_upstream_model(&request.model).to_owned();
let model_limits = provider.find_model(&upstream_model).map(|m| m.limits);
let outbound_ctx = OutboundCtx {
route: route.as_ref(),
endpoint: &provider.endpoint,
api_key: upstream_api_key,
request: &request,
upstream_model: &upstream_model,
model_limits,
};
let outcome = match upstream.send(outbound_ctx).await {
Ok(o) => o,
Err(e) => {
audit_upstream_failure(&audit, upstream.provider_tag(), &request.model, &e).await;
return Err(DispatchError::Recorded(e));
},
};
let response = finalize(
outcome,
FinalizeCtx {
audit: Arc::clone(&audit),
db: db.clone(),
ai_request_id: ai_request_id.clone(),
policy,
inbound,
request_model: request.model.clone(),
},
)
.await;
Ok(attach_request_id(response, &ai_request_id))
}
}
async fn enforce_request_safety(
db: &DbPool,
ai_request_id: &AiRequestId,
request: &CanonicalRequest,
safety: &SafetyConfig,
audit: &GatewayAudit,
) -> Result<(), DispatchError> {
let findings = run_request_safety_scan(db, ai_request_id, request, safety).await;
let Some(finding) = findings
.iter()
.find(|f| safety.block_categories.contains(&f.category))
else {
return Ok(());
};
let msg = format!(
"request blocked by safety policy: category '{}'",
finding.category
);
tracing::warn!(
ai_request_id = %ai_request_id,
category = %finding.category,
scanner = %finding.scanner,
"Gateway blocked request by safety policy"
);
if let Err(e) = audit.fail(&msg).await {
tracing::warn!(error = %e, "safety-block audit fail failed");
}
Err(DispatchError::Recorded(
SafetyBlocked {
category: finding.category.clone(),
message: msg,
}
.into(),
))
}
async fn audit_upstream_failure(
audit: &GatewayAudit,
provider: &str,
model: &str,
error: &anyhow::Error,
) {
tracing::warn!(
provider = %provider,
model = %model,
error = %error,
"gateway upstream call failed"
);
if let Err(audit_err) = audit.fail(&error.to_string()).await {
tracing::warn!(error = %audit_err, "upstream audit fail failed");
}
}