ZDDC/zddc/internal/handler/middleware.go
ZDDC 411f49169b feat(server): tee access log to a rotated file for on-disk audit trail
Add --access-log <path> (env ZDDC_ACCESS_LOG). When set, every access-
log record is written as a JSON line to the configured file in
addition to the existing slog.Default() stderr output. Empty (default)
keeps the prior behavior — stderr only.

Rotation via gopkg.in/natefinch/lumberjack.v2:
  100 MB per file, 10 backups, 90-day max age, gzip rotated files.

Operator usage (e.g. behind a Caddy/quadlet stack):
  zddc-server --access-log /srv/.zddc.d/logs/access.log ...

Architecture:
  AccessLogMiddleware now takes an optional *slog.Logger. main.go wires
  it via setupAccessAuditLog() which builds a slog.JSONHandler over a
  lumberjack rotator. Stderr emission stays via slog.Default(); the
  audit logger gets the same fields in line-delimited JSON, the format
  every standard log shipper (Vector, Loki, fluentbit, journalbeat)
  parses natively.

Tests cover the audit logger receiving the same email/path/status
fields as the stderr stream.
2026-05-04 07:49:17 -05:00

121 lines
3.8 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.
//
// Always emits to slog.Default() (stderr) so server-lifecycle logs and
// access logs share an output stream by default.
//
// If `auditLogger` is non-nil, the same structured fields are also written
// to it. The intended caller wires up auditLogger with a JSON handler
// pointing at a rotating file (see cmd/zddc-server's setupAccessAuditLog),
// so an operator gets a persisted audit trail on disk in addition to the
// stderr stream — useful when stderr is not journald-captured (e.g.
// container logging where the orchestrator drops stderr after restarts).
func AccessLogMiddleware(auditLogger *slog.Logger, 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"
}
args := []any{
"ts", start.Format(time.RFC3339),
"email", email,
"method", r.Method,
"path", r.URL.Path,
"status", wrapped.status,
"bytes", wrapped.bytes,
"duration_ms", durationMs,
}
// Stderr stream (existing behavior).
slog.Info("access", args...)
// Audit file (when configured). Same fields, separate handler so
// the file can be JSON-formatted regardless of stderr's handler.
if auditLogger != nil {
auditLogger.Info("access", args...)
}
})
}