feat: extend request logs with auth & DB info (#17304)

Closes #16903

coderd/httpmw/loggermw/logger.go

@@ -0,0 +1,203 @@
+package loggermw
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+
+	"cdr.dev/slog"
+	"github.com/coder/coder/v2/coderd/httpapi"
+	"github.com/coder/coder/v2/coderd/rbac"
+	"github.com/coder/coder/v2/coderd/tracing"
+)
+
+func Logger(log slog.Logger) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+			start := time.Now()
+
+			sw, ok := rw.(*tracing.StatusWriter)
+			if !ok {
+				panic(fmt.Sprintf("ResponseWriter not a *tracing.StatusWriter; got %T", rw))
+			}
+
+			httplog := log.With(
+				slog.F("host", httpapi.RequestHost(r)),
+				slog.F("path", r.URL.Path),
+				slog.F("proto", r.Proto),
+				slog.F("remote_addr", r.RemoteAddr),
+				// Include the start timestamp in the log so that we have the
+				// source of truth. There is at least a theoretical chance that
+				// there can be a delay between `next.ServeHTTP` ending and us
+				// actually logging the request. This can also be useful when
+				// filtering logs that started at a certain time (compared to
+				// trying to compute the value).
+				slog.F("start", start),
+			)
+
+			logContext := NewRequestLogger(httplog, r.Method, start)
+
+			ctx := WithRequestLogger(r.Context(), logContext)
+
+			next.ServeHTTP(sw, r.WithContext(ctx))
+
+			// Don't log successful health check requests.
+			if r.URL.Path == "/api/v2" && sw.Status == http.StatusOK {
+				return
+			}
+
+			// For status codes 500 and higher we
+			// want to log the response body.
+			if sw.Status >= http.StatusInternalServerError {
+				logContext.WithFields(
+					slog.F("response_body", string(sw.ResponseBody())),
+				)
+			}
+
+			logContext.WriteLog(r.Context(), sw.Status)
+		})
+	}
+}
+
+type RequestLogger interface {
+	WithFields(fields ...slog.Field)
+	WriteLog(ctx context.Context, status int)
+	WithAuthContext(actor rbac.Subject)
+}
+
+type SlogRequestLogger struct {
+	log     slog.Logger
+	written bool
+	message string
+	start   time.Time
+	// Protects actors map for concurrent writes.
+	mu     sync.RWMutex
+	actors map[rbac.SubjectType]rbac.Subject
+}
+
+var _ RequestLogger = &SlogRequestLogger{}
+
+func NewRequestLogger(log slog.Logger, message string, start time.Time) RequestLogger {
+	return &SlogRequestLogger{
+		log:     log,
+		written: false,
+		message: message,
+		start:   start,
+		actors:  make(map[rbac.SubjectType]rbac.Subject),
+	}
+}
+
+func (c *SlogRequestLogger) WithFields(fields ...slog.Field) {
+	c.log = c.log.With(fields...)
+}
+
+func (c *SlogRequestLogger) WithAuthContext(actor rbac.Subject) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.actors[actor.Type] = actor
+}
+
+func (c *SlogRequestLogger) addAuthContextFields() {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	usr, ok := c.actors[rbac.SubjectTypeUser]
+	if ok {
+		c.log = c.log.With(
+			slog.F("requestor_id", usr.ID),
+			slog.F("requestor_name", usr.FriendlyName),
+			slog.F("requestor_email", usr.Email),
+		)
+	} else {
+		// If there is no user, we log the requestor name for the first
+		// actor in a defined order.
+		for _, v := range actorLogOrder {
+			subj, ok := c.actors[v]
+			if !ok {
+				continue
+			}
+			c.log = c.log.With(
+				slog.F("requestor_name", subj.FriendlyName),
+			)
+			break
+		}
+	}
+}
+
+var actorLogOrder = []rbac.SubjectType{
+	rbac.SubjectTypeAutostart,
+	rbac.SubjectTypeCryptoKeyReader,
+	rbac.SubjectTypeCryptoKeyRotator,
+	rbac.SubjectTypeHangDetector,
+	rbac.SubjectTypeNotifier,
+	rbac.SubjectTypePrebuildsOrchestrator,
+	rbac.SubjectTypeProvisionerd,
+	rbac.SubjectTypeResourceMonitor,
+	rbac.SubjectTypeSystemReadProvisionerDaemons,
+	rbac.SubjectTypeSystemRestricted,
+}
+
+func (c *SlogRequestLogger) WriteLog(ctx context.Context, status int) {
+	if c.written {
+		return
+	}
+	c.written = true
+	end := time.Now()
+
+	// Right before we write the log, we try to find the user in the actors
+	// and add the fields to the log.
+	c.addAuthContextFields()
+
+	logger := c.log.With(
+		slog.F("took", end.Sub(c.start)),
+		slog.F("status_code", status),
+		slog.F("latency_ms", float64(end.Sub(c.start)/time.Millisecond)),
+	)
+
+	// If the request is routed, add the route parameters to the log.
+	if chiCtx := chi.RouteContext(ctx); chiCtx != nil {
+		urlParams := chiCtx.URLParams
+		routeParamsFields := make([]slog.Field, 0, len(urlParams.Keys))
+
+		for k, v := range urlParams.Keys {
+			if urlParams.Values[k] != "" {
+				routeParamsFields = append(routeParamsFields, slog.F("params_"+v, urlParams.Values[k]))
+			}
+		}
+
+		if len(routeParamsFields) > 0 {
+			logger = logger.With(routeParamsFields...)
+		}
+	}
+
+	// We already capture most of this information in the span (minus
+	// the response body which we don't want to capture anyways).
+	tracing.RunWithoutSpan(ctx, func(ctx context.Context) {
+		// We should not log at level ERROR for 5xx status codes because 5xx
+		// includes proxy errors etc. It also causes slogtest to fail
+		// instantly without an error message by default.
+		if status >= http.StatusInternalServerError {
+			logger.Warn(ctx, c.message)
+		} else {
+			logger.Debug(ctx, c.message)
+		}
+	})
+}
+
+type logContextKey struct{}
+
+func WithRequestLogger(ctx context.Context, rl RequestLogger) context.Context {
+	return context.WithValue(ctx, logContextKey{}, rl)
+}
+
+func RequestLoggerFromContext(ctx context.Context) RequestLogger {
+	val := ctx.Value(logContextKey{})
+	if logCtx, ok := val.(RequestLogger); ok {
+		return logCtx
+	}
+	return nil
+}