ZDDC/zddc/internal/handler/middleware.go
ZDDC 15ccf554d2 feat(zddc-server): debug-level dump of every request's full headers
ACLMiddleware now slog.Debug's the configured email-header name, the
observed value at that name, and the full r.Header map on every request.
Off at the default INFO log level; enable per-pod with ZDDC_LOG_LEVEL=debug.

Motivated by debugging the X-Auth-Request-Email passthrough chain — when
access logs show email=anonymous, /.admin/whoami is unreachable (the
admin gate requires a non-empty email, which is the chicken-and-egg).
The debug log line dumps headers without the gate, so an operator can
identify whichever header name the upstream proxy is actually setting
(X-Forwarded-User, X-Forwarded-Email, Remote-User, X-Authentik-Email,
etc.) and adjust ZDDC_EMAIL_HEADER accordingly.

The debug-level dump captures auth tokens and cookies along with
everything else; safe in dev clusters, not appropriate for production
unless the operator is comfortable with the trade-off. README documents
the trade-off in the Admin Debug Page section.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-28 17:53:55 -05:00

102 lines
2.9 KiB
Go

package handler
import (
"context"
"net/http"
"time"
"codeberg.org/VARASYS/ZDDC/zddc/internal/config"
"log/slog"
)
type contextKey string
// EmailKey is the context key for the authenticated user's email.
const EmailKey contextKey = "email"
// ACLMiddleware extracts the user email from the configured header and stores
// it in the request context. It does NOT enforce ACL itself — each handler
// performs its own ACL check via zddc.EffectivePolicy / zddc.AllowedWithChain.
func ACLMiddleware(cfg config.Config, next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
email := r.Header.Get(cfg.EmailHeader)
// DEBUG-level header dump for diagnosing proxy / SSO header
// passthrough. Off by default (LogLevel info); enable with
// ZDDC_LOG_LEVEL=debug. Logs the configured header name, the
// observed value at that name, and the full request header
// map so an operator can see exactly what reached the binary.
// Note: at debug level this also captures auth tokens, cookies,
// and anything else upstream proxies forward — only enable in
// trusted environments.
slog.Debug("request headers",
"configured", cfg.EmailHeader,
"observed", email,
"headers", r.Header)
ctx := context.WithValue(r.Context(), EmailKey, email)
next.ServeHTTP(w, r.WithContext(ctx))
})
}
// EmailFromContext extracts the user email from the request context.
func EmailFromContext(r *http.Request) string {
if v, ok := r.Context().Value(EmailKey).(string); ok {
return v
}
return ""
}
// responseWriter wraps http.ResponseWriter to capture status code and bytes written.
type responseWriter struct {
http.ResponseWriter
status int
bytes int
wrote bool
}
// WriteHeader records the status code and writes it to the underlying ResponseWriter.
func (rw *responseWriter) WriteHeader(code int) {
rw.status = code
rw.wrote = true
rw.ResponseWriter.WriteHeader(code)
}
// Write records the bytes written and writes to the underlying ResponseWriter.
func (rw *responseWriter) Write(b []byte) (int, error) {
n, err := rw.ResponseWriter.Write(b)
rw.bytes += n
return n, err
}
// AccessLogMiddleware logs a structured line per HTTP request after the response is written.
func AccessLogMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Capture request start time
start := time.Now()
// Wrap the ResponseWriter
wrapped := &responseWriter{ResponseWriter: w, status: 200}
// Serve the request
next.ServeHTTP(wrapped, r)
// Calculate duration
durationMs := int(time.Since(start).Milliseconds())
// Get email from context
email := EmailFromContext(r)
if email == "" {
email = "anonymous"
}
// Log access
slog.Info("access",
"ts", start.Format(time.RFC3339),
"email", email,
"method", r.Method,
"path", r.URL.Path,
"status", wrapped.status,
"bytes", wrapped.bytes,
"duration_ms", durationMs,
)
})
}