feat: log long-lived connections acceptance (#17219)

Closes #16904

coderd/httpmw/logger.go

@@ -35,42 +35,93 @@ func Logger(log slog.Logger) func(next http.Handler) http.Handler {
 				slog.F("start", start),
 			)
 
-			next.ServeHTTP(sw, r)
+			logContext := NewRequestLogger(httplog, r.Method, start)
 
-			end := time.Now()
+			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
 			}
 
-			httplog = httplog.With(
-				slog.F("took", end.Sub(start)),
-				slog.F("status_code", sw.Status),
-				slog.F("latency_ms", float64(end.Sub(start)/time.Millisecond)),
-			)
-
-			// For status codes 400 and higher we
+			// For status codes 500 and higher we
 			// want to log the response body.
 			if sw.Status >= http.StatusInternalServerError {
-				httplog = httplog.With(
+				logContext.WithFields(
 					slog.F("response_body", string(sw.ResponseBody())),
 				)
 			}
 
-			// 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.
-			logLevelFn := httplog.Debug
-			if sw.Status >= http.StatusInternalServerError {
-				logLevelFn = httplog.Warn
-			}
-
-			// We already capture most of this information in the span (minus
-			// the response body which we don't want to capture anyways).
-			tracing.RunWithoutSpan(r.Context(), func(ctx context.Context) {
-				logLevelFn(ctx, r.Method)
-			})
+			logContext.WriteLog(r.Context(), sw.Status)
 		})
 	}
 }
+
+type RequestLogger interface {
+	WithFields(fields ...slog.Field)
+	WriteLog(ctx context.Context, status int)
+}
+
+type SlogRequestLogger struct {
+	log     slog.Logger
+	written bool
+	message string
+	start   time.Time
+}
+
+var _ RequestLogger = &SlogRequestLogger{}
+
+func NewRequestLogger(log slog.Logger, message string, start time.Time) RequestLogger {
+	return &SlogRequestLogger{
+		log:     log,
+		written: false,
+		message: message,
+		start:   start,
+	}
+}
+
+func (c *SlogRequestLogger) WithFields(fields ...slog.Field) {
+	c.log = c.log.With(fields...)
+}
+
+func (c *SlogRequestLogger) WriteLog(ctx context.Context, status int) {
+	if c.written {
+		return
+	}
+	c.written = true
+	end := time.Now()
+
+	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)),
+	)
+	// 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
+}

coderd/httpmw/logger_internal_test.go

@@ -0,0 +1,174 @@
+package httpmw
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"cdr.dev/slog"
+	"github.com/coder/coder/v2/coderd/tracing"
+	"github.com/coder/coder/v2/testutil"
+	"github.com/coder/websocket"
+)
+
+func TestRequestLogger_WriteLog(t *testing.T) {
+	t.Parallel()
+	ctx := context.Background()
+
+	sink := &fakeSink{}
+	logger := slog.Make(sink)
+	logger = logger.Leveled(slog.LevelDebug)
+	logCtx := NewRequestLogger(logger, "GET", time.Now())
+
+	// Add custom fields
+	logCtx.WithFields(
+		slog.F("custom_field", "custom_value"),
+	)
+
+	// Write log for 200 status
+	logCtx.WriteLog(ctx, http.StatusOK)
+
+	require.Len(t, sink.entries, 1, "log was written twice")
+
+	require.Equal(t, sink.entries[0].Message, "GET")
+
+	require.Equal(t, sink.entries[0].Fields[0].Value, "custom_value")
+
+	// Attempt to write again (should be skipped).
+	logCtx.WriteLog(ctx, http.StatusInternalServerError)
+
+	require.Len(t, sink.entries, 1, "log was written twice")
+}
+
+func TestLoggerMiddleware_SingleRequest(t *testing.T) {
+	t.Parallel()
+
+	sink := &fakeSink{}
+	logger := slog.Make(sink)
+	logger = logger.Leveled(slog.LevelDebug)
+
+	ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
+	defer cancel()
+
+	// Create a test handler to simulate an HTTP request
+	testHandler := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		rw.WriteHeader(http.StatusOK)
+		_, _ = rw.Write([]byte("OK"))
+	})
+
+	// Wrap the test handler with the Logger middleware
+	loggerMiddleware := Logger(logger)
+	wrappedHandler := loggerMiddleware(testHandler)
+
+	// Create a test HTTP request
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "/test-path", nil)
+	require.NoError(t, err, "failed to create request")
+
+	sw := &tracing.StatusWriter{ResponseWriter: httptest.NewRecorder()}
+
+	// Serve the request
+	wrappedHandler.ServeHTTP(sw, req)
+
+	require.Len(t, sink.entries, 1, "log was written twice")
+
+	require.Equal(t, sink.entries[0].Message, "GET")
+
+	fieldsMap := make(map[string]interface{})
+	for _, field := range sink.entries[0].Fields {
+		fieldsMap[field.Name] = field.Value
+	}
+
+	// Check that the log contains the expected fields
+	requiredFields := []string{"host", "path", "proto", "remote_addr", "start", "took", "status_code", "latency_ms"}
+	for _, field := range requiredFields {
+		_, exists := fieldsMap[field]
+		require.True(t, exists, "field %q is missing in log fields", field)
+	}
+
+	require.Len(t, sink.entries[0].Fields, len(requiredFields), "log should contain only the required fields")
+
+	// Check value of the status code
+	require.Equal(t, fieldsMap["status_code"], http.StatusOK)
+}
+
+func TestLoggerMiddleware_WebSocket(t *testing.T) {
+	t.Parallel()
+	ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitShort)
+	defer cancel()
+
+	sink := &fakeSink{
+		newEntries: make(chan slog.SinkEntry, 2),
+	}
+	logger := slog.Make(sink)
+	logger = logger.Leveled(slog.LevelDebug)
+	done := make(chan struct{})
+	wg := sync.WaitGroup{}
+	// Create a test handler to simulate a WebSocket connection
+	testHandler := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		conn, err := websocket.Accept(rw, r, nil)
+		if !assert.NoError(t, err, "failed to accept websocket") {
+			return
+		}
+		defer conn.Close(websocket.StatusGoingAway, "")
+
+		requestLgr := RequestLoggerFromContext(r.Context())
+		requestLgr.WriteLog(r.Context(), http.StatusSwitchingProtocols)
+		// Block so we can be sure the end of the middleware isn't being called.
+		wg.Wait()
+	})
+
+	// Wrap the test handler with the Logger middleware
+	loggerMiddleware := Logger(logger)
+	wrappedHandler := loggerMiddleware(testHandler)
+
+	// RequestLogger expects the ResponseWriter to be *tracing.StatusWriter
+	customHandler := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		defer close(done)
+		sw := &tracing.StatusWriter{ResponseWriter: rw}
+		wrappedHandler.ServeHTTP(sw, r)
+	})
+
+	srv := httptest.NewServer(customHandler)
+	defer srv.Close()
+	wg.Add(1)
+	// nolint: bodyclose
+	conn, _, err := websocket.Dial(ctx, srv.URL, nil)
+	require.NoError(t, err, "failed to dial WebSocket")
+	defer conn.Close(websocket.StatusNormalClosure, "")
+
+	// Wait for the log from within the handler
+	newEntry := testutil.RequireRecvCtx(ctx, t, sink.newEntries)
+	require.Equal(t, newEntry.Message, "GET")
+
+	// Signal the websocket handler to return (and read to handle the close frame)
+	wg.Done()
+	_, _, err = conn.Read(ctx)
+	require.ErrorAs(t, err, &websocket.CloseError{}, "websocket read should fail with close error")
+
+	// Wait for the request to finish completely and verify we only logged once
+	_ = testutil.RequireRecvCtx(ctx, t, done)
+	require.Len(t, sink.entries, 1, "log was written twice")
+}
+
+type fakeSink struct {
+	entries    []slog.SinkEntry
+	newEntries chan slog.SinkEntry
+}
+
+func (s *fakeSink) LogEntry(_ context.Context, e slog.SinkEntry) {
+	s.entries = append(s.entries, e)
+	if s.newEntries != nil {
+		select {
+		case s.newEntries <- e:
+		default:
+		}
+	}
+}
+
+func (*fakeSink) Sync() {}

coderd/httpmw/loggermock/loggermock.go

@@ -0,0 +1,70 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: github.com/coder/coder/v2/coderd/httpmw (interfaces: RequestLogger)
+//
+// Generated by this command:
+//
+//	mockgen -destination=loggermock/loggermock.go -package=loggermock . RequestLogger
+//
+
+// Package loggermock is a generated GoMock package.
+package loggermock
+
+import (
+	context "context"
+	reflect "reflect"
+
+	slog "cdr.dev/slog"
+	gomock "go.uber.org/mock/gomock"
+)
+
+// MockRequestLogger is a mock of RequestLogger interface.
+type MockRequestLogger struct {
+	ctrl     *gomock.Controller
+	recorder *MockRequestLoggerMockRecorder
+	isgomock struct{}
+}
+
+// MockRequestLoggerMockRecorder is the mock recorder for MockRequestLogger.
+type MockRequestLoggerMockRecorder struct {
+	mock *MockRequestLogger
+}
+
+// NewMockRequestLogger creates a new mock instance.
+func NewMockRequestLogger(ctrl *gomock.Controller) *MockRequestLogger {
+	mock := &MockRequestLogger{ctrl: ctrl}
+	mock.recorder = &MockRequestLoggerMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockRequestLogger) EXPECT() *MockRequestLoggerMockRecorder {
+	return m.recorder
+}
+
+// WithFields mocks base method.
+func (m *MockRequestLogger) WithFields(fields ...slog.Field) {
+	m.ctrl.T.Helper()
+	varargs := []any{}
+	for _, a := range fields {
+		varargs = append(varargs, a)
+	}
+	m.ctrl.Call(m, "WithFields", varargs...)
+}
+
+// WithFields indicates an expected call of WithFields.
+func (mr *MockRequestLoggerMockRecorder) WithFields(fields ...any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "WithFields", reflect.TypeOf((*MockRequestLogger)(nil).WithFields), fields...)
+}
+
+// WriteLog mocks base method.
+func (m *MockRequestLogger) WriteLog(ctx context.Context, status int) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "WriteLog", ctx, status)
+}
+
+// WriteLog indicates an expected call of WriteLog.
+func (mr *MockRequestLoggerMockRecorder) WriteLog(ctx, status any) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "WriteLog", reflect.TypeOf((*MockRequestLogger)(nil).WriteLog), ctx, status)
+}