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//! Drift tracking middleware
//!
//! This middleware integrates drift budget evaluation and consumer usage tracking
//! with contract diff analysis.
// Uses DriftBudgetEngine + ContractDiffAnalyzer which stay in core.
#![allow(deprecated)]
use axum::{body::Body, extract::Request, http::Response, middleware::Next};
use mockforge_contracts::consumer_contracts::{ConsumerBreakingChangeDetector, UsageRecorder};
use mockforge_core::{
ai_contract_diff::ContractDiffAnalyzer,
contract_drift::DriftBudgetEngine,
incidents::{IncidentManager, IncidentSeverity, IncidentType},
openapi::OpenApiSpec,
};
use mockforge_foundation::contract_drift_types::DriftResult;
use serde_json::Value;
use std::collections::HashMap;
use std::sync::Arc;
use tracing::{debug, warn};
/// Maximum request body size to buffer for drift tracking.
///
/// Issue #79 — see `contract_diff_middleware`. Same root cause: the
/// old hard-coded 1 MiB cap, paired with the over-cap branch
/// substituting `Body::empty()`, broke downstream handlers on large
/// chunked uploads. Configurable via `MOCKFORGE_DRIFT_MAX_BODY_MB`.
fn max_drift_body_size() -> usize {
const DEFAULT_MB: usize = 10;
std::env::var("MOCKFORGE_DRIFT_MAX_BODY_MB")
.ok()
.and_then(|v| v.parse::<usize>().ok())
.unwrap_or(DEFAULT_MB)
.saturating_mul(1024 * 1024)
}
/// State for drift tracking middleware
#[derive(Clone)]
pub struct DriftTrackingState {
/// Contract diff analyzer
pub diff_analyzer: Option<Arc<ContractDiffAnalyzer>>,
/// OpenAPI spec (if available)
pub spec: Option<Arc<OpenApiSpec>>,
/// Drift budget engine
pub drift_engine: Arc<DriftBudgetEngine>,
/// Incident manager
pub incident_manager: Arc<IncidentManager>,
/// Usage recorder for consumer contracts
pub usage_recorder: Arc<UsageRecorder>,
/// Consumer breaking change detector
pub consumer_detector: Arc<ConsumerBreakingChangeDetector>,
/// Whether drift tracking is enabled
pub enabled: bool,
}
/// Middleware to track drift and consumer usage (with state from extensions)
///
/// This middleware requires response body buffering middleware to be applied first.
/// The response body is extracted from buffered response extensions.
pub async fn drift_tracking_middleware_with_extensions(
req: Request<Body>,
next: Next,
) -> Response<Body> {
// Extract state from request extensions
let state = req.extensions().get::<DriftTrackingState>().cloned();
let state = if let Some(state) = state {
state
} else {
// No state available, skip drift tracking
return next.run(req).await;
};
if !state.enabled {
return next.run(req).await;
}
let method = req.method().to_string();
let path = req.uri().path().to_string();
let max_body = max_drift_body_size();
// Issue #79 — pre-check Content-Length so we skip capture cleanly
// for over-cap requests instead of consuming the body and then
// substituting `Body::empty()` (which broke downstream handlers).
let content_length = req
.headers()
.get(http::header::CONTENT_LENGTH)
.and_then(|v| v.to_str().ok())
.and_then(|s| s.parse::<usize>().ok());
if let Some(len) = content_length {
if len > max_body {
debug!(
"drift_tracking: skipping capture for {} {} — content-length {} > cap {}",
method, path, len, max_body
);
return next.run(req).await;
}
}
// Extract consumer identifier and headers from request
let consumer_id = extract_consumer_id(&req);
// Extract headers for capture
let captured_headers = extract_headers_for_capture(&req);
// Buffer the request body so we can capture it and still forward it
let (parts, body) = req.into_parts();
let body_bytes = match axum::body::to_bytes(body, max_body).await {
Ok(b) => b,
Err(_) => {
// Chunked over-cap body — body partially consumed and we
// cannot rebuild. 413 PayloadTooLarge instead of the old
// silent `Body::empty()` substitution. Issue #79.
return Response::builder()
.status(http::StatusCode::PAYLOAD_TOO_LARGE)
.header(
http::header::CONTENT_TYPE,
"application/json",
)
.body(Body::from(format!(
r#"{{"error":"PAYLOAD_TOO_LARGE","message":"chunked request body exceeded drift_tracking capture cap (~{} MiB); raise MOCKFORGE_DRIFT_MAX_BODY_MB or send Content-Length"}}"#,
max_body / (1024 * 1024)
)))
.unwrap_or_else(|_| Response::new(Body::from("payload too large")));
}
};
// Try to parse body as JSON for structured capture
let captured_body = if !body_bytes.is_empty() {
serde_json::from_slice::<Value>(&body_bytes).ok()
} else {
None
};
// Reconstruct the request with the buffered body
let req = Request::from_parts(parts, Body::from(body_bytes));
// Process request and get response
let response = next.run(req).await;
// Extract response body for consumer usage tracking
let response_body = extract_response_body(&response);
// Record consumer usage if consumer is identified
if let Some(ref consumer_id) = consumer_id {
if let Some(body) = &response_body {
state.usage_recorder.record_usage(consumer_id, &path, &method, Some(body)).await;
}
}
// Perform contract diff analysis if analyzer and spec are available
if let (Some(ref analyzer), Some(ref spec)) = (&state.diff_analyzer, &state.spec) {
// Create captured request with body and headers
let mut captured = mockforge_core::ai_contract_diff::CapturedRequest::new(
&method,
&path,
"drift_tracking",
)
.with_headers(captured_headers)
.with_response(response.status().as_u16(), response_body.clone());
if let Some(body_value) = captured_body {
captured = captured.with_body(body_value);
}
// Analyze request against contract
match analyzer.analyze(&captured, spec).await {
Ok(diff_result) => {
// Evaluate drift budget
let drift_result = state.drift_engine.evaluate(&diff_result, &path, &method);
// Emit Prometheus gauges for the drift dashboard (#678). The
// workspace_id is not yet plumbed through the middleware —
// pass an empty label so a single global series records,
// matching the pattern used for the non-workspace
// `pillar_tracking` calls below. When workspace identification
// lands we can switch this label to the resolved id.
mockforge_observability::get_global_registry().record_drift_evaluation(
mockforge_observability::DriftEvaluationSample {
workspace_id: "",
endpoint: &path,
method: &method,
total: drift_result.metrics.total_changes,
breaking: drift_result.breaking_changes,
potentially_breaking: drift_result.potentially_breaking_changes,
budget_exceeded: drift_result.budget_exceeded,
},
);
// #677 — when analytics is installed, fire a drift_percentage
// sample at the analytics sqlite. Stays a no-op when the
// global DB hasn't been initialised, so OSS quick-start
// doesn't accidentally create a sqlite file.
//
// Heuristic for total/drifting: total_changes counts the
// observed mismatches (the "denominator" for how many things
// we looked at this request), and breaking + potentially-
// breaking is what counts as drift. Recorded per-request so
// the dashboard's time-series view shows the live trend.
let total = i64::from(drift_result.metrics.total_changes);
let drifting = i64::from(drift_result.breaking_changes)
+ i64::from(drift_result.potentially_breaking_changes);
mockforge_analytics::record_drift_percentage_async(
String::new(), // workspace_id — see Prometheus emission note
None,
total,
drifting,
);
// Record contracts pillar usage for drift detection
mockforge_core::pillar_tracking::record_contracts_usage(
None, // workspace_id could be extracted from request if available
None,
"drift_detection",
serde_json::json!({
"endpoint": path,
"method": method,
"breaking_changes": drift_result.breaking_changes,
"non_breaking_changes": drift_result.non_breaking_changes,
"incident": drift_result.should_create_incident
}),
)
.await;
// If this endpoint has a drift budget configured, record that so
// the Contracts pillar dashboard can count distinct budgeted endpoints.
let endpoint_key = format!("{} {}", method, path);
let budget_config = state.drift_engine.config();
if budget_config.enabled
&& (budget_config.per_endpoint_budgets.contains_key(&endpoint_key)
|| budget_config.default_budget.is_some())
{
mockforge_core::pillar_tracking::record_contracts_usage(
None,
None,
"drift_budget_configured",
serde_json::json!({
"endpoint": endpoint_key,
}),
)
.await;
}
// Create incident if budget is exceeded or breaking changes detected
if drift_result.should_create_incident {
let incident_type = if drift_result.breaking_changes > 0 {
IncidentType::BreakingChange
} else {
IncidentType::ThresholdExceeded
};
let severity = determine_severity(&drift_result);
let details = serde_json::json!({
"breaking_changes": drift_result.breaking_changes,
"non_breaking_changes": drift_result.non_breaking_changes,
"breaking_mismatches": drift_result.breaking_mismatches,
"non_breaking_mismatches": drift_result.non_breaking_mismatches,
"budget_exceeded": drift_result.budget_exceeded,
});
// Create incident with before/after samples
// Extract before/after samples from diff result if available
let before_sample = Some(serde_json::json!({
"contract_format": diff_result.metadata.contract_format,
"contract_version": diff_result.metadata.contract_version,
"endpoint": path,
"method": method,
}));
let after_sample = Some(serde_json::json!({
"mismatches": diff_result.mismatches,
"recommendations": diff_result.recommendations,
"corrections": diff_result.corrections,
}));
let _incident = state
.incident_manager
.create_incident_with_samples(
path.clone(),
method.clone(),
incident_type,
severity,
details,
None, // budget_id
None, // workspace_id
None, // sync_cycle_id
None, // contract_diff_id (could be generated from diff_result)
before_sample,
after_sample,
Some(drift_result.fitness_test_results.clone()), // fitness_test_results
drift_result.consumer_impact.clone(), // affected_consumers
Some(mockforge_foundation::protocol::Protocol::Http), // protocol
)
.await;
warn!(
"Drift incident created: {} {} - {} breaking changes, {} non-breaking changes",
method, path, drift_result.breaking_changes, drift_result.non_breaking_changes
);
}
// Check for consumer-specific violations
if let Some(ref consumer_id) = consumer_id {
let violations = state
.consumer_detector
.detect_violations(consumer_id, &path, &method, &diff_result, None)
.await;
if !violations.is_empty() {
warn!(
"Consumer {} has {} violations on {} {}",
consumer_id,
violations.len(),
method,
path
);
}
}
}
Err(e) => {
debug!("Contract diff analysis failed: {}", e);
}
}
}
response
}
/// Extract consumer identifier from request
fn extract_consumer_id(req: &Request<Body>) -> Option<String> {
// Try to extract from various sources:
// 1. X-Consumer-ID header
if let Some(consumer_id) = req.headers().get("x-consumer-id").and_then(|h| h.to_str().ok()) {
return Some(consumer_id.to_string());
}
// 2. X-Workspace-ID header (for workspace-based consumers)
if let Some(workspace_id) = req.headers().get("x-workspace-id").and_then(|h| h.to_str().ok()) {
return Some(format!("workspace:{}", workspace_id));
}
// 3. API key from header
if let Some(api_key) = req
.headers()
.get("x-api-key")
.or_else(|| req.headers().get("authorization"))
.and_then(|h| h.to_str().ok())
{
// Hash the API key for privacy
use sha2::{Digest, Sha256};
let mut hasher = Sha256::new();
hasher.update(api_key.as_bytes());
let hash = format!("{:x}", hasher.finalize());
return Some(format!("api_key:{}", hash));
}
None
}
/// Extract safe headers for drift capture
fn extract_headers_for_capture(req: &Request<Body>) -> HashMap<String, String> {
let safe_headers = [
"accept",
"accept-encoding",
"content-type",
"content-length",
"user-agent",
];
let mut captured = HashMap::new();
for name in safe_headers {
if let Some(value) = req.headers().get(name).and_then(|v| v.to_str().ok()) {
captured.insert(name.to_string(), value.to_string());
}
}
captured
}
/// Extract response body as JSON value
fn extract_response_body(response: &Response<Body>) -> Option<Value> {
// Try to get buffered response from extensions
if let Some(buffered) = crate::middleware::get_buffered_response(response) {
return buffered.json();
}
// If not buffered, try to parse from response body
// Note: This requires the response body to be buffered by upstream middleware
None
}
/// Determine incident severity from drift result
fn determine_severity(drift_result: &DriftResult) -> IncidentSeverity {
if drift_result.breaking_changes > 0 {
// Check if any breaking mismatch is critical
if drift_result
.breaking_mismatches
.iter()
.any(|m| m.severity == mockforge_core::ai_contract_diff::MismatchSeverity::Critical)
{
return IncidentSeverity::Critical;
}
// Check if any breaking mismatch is high
if drift_result
.breaking_mismatches
.iter()
.any(|m| m.severity == mockforge_core::ai_contract_diff::MismatchSeverity::High)
{
return IncidentSeverity::High;
}
return IncidentSeverity::Medium;
}
// Non-breaking changes are lower severity
if drift_result.non_breaking_changes > 5 {
IncidentSeverity::Medium
} else {
IncidentSeverity::Low
}
}