fix: pass dial options to FUSE mounts (#319)

This is a port of
GoogleCloudPlatform/cloud-sql-proxy#1737.

internal/proxy/proxy.go

@@ -362,19 +362,13 @@ type Client struct {
 	// all AlloyDB instances.
 	connCount uint64
 
-	// maxConns is the maximum number of allowed connections tracked by
-	// connCount. If not set, there is no limit.
-	maxConns uint64
+	conf *Config
 
 	dialer alloydb.Dialer
 
 	// mnts is a list of all mounted sockets for this client
 	mnts []*socketMount
 
-	// waitOnClose is the maximum duration to wait for open connections to close
-	// when shutting down.
-	waitOnClose time.Duration
-
 	logger alloydb.Logger
 
 	fuseMount
@@ -396,10 +390,9 @@ func NewClient(ctx context.Context, d alloydb.Dialer, l alloydb.Logger, conf *Co
 	}
 
 	c := &Client{
-		logger:      l,
-		dialer:      d,
-		maxConns:    conf.MaxConnections,
-		waitOnClose: conf.WaitOnClose,
+		logger: l,
+		dialer: d,
+		conf:   conf,
 	}
 
 	if conf.FUSEDir != "" {
@@ -485,7 +478,7 @@ func (c *Client) CheckConnections(ctx context.Context) (int, error) {
 // ConnCount returns the number of open connections and the maximum allowed
 // connections. Returns 0 when the maximum allowed connections have not been set.
 func (c *Client) ConnCount() (uint64, uint64) {
-	return atomic.LoadUint64(&c.connCount), c.maxConns
+	return atomic.LoadUint64(&c.connCount), c.conf.MaxConnections
 }
 
 // Serve starts proxying connections for all configured instances using the
@@ -565,13 +558,13 @@ func (c *Client) Close() error {
 	if cErr != nil {
 		mErr = append(mErr, cErr)
 	}
-	if c.waitOnClose == 0 {
+	if c.conf.WaitOnClose == 0 {
 		if len(mErr) > 0 {
 			return mErr
 		}
 		return nil
 	}
-	timeout := time.After(c.waitOnClose)
+	timeout := time.After(c.conf.WaitOnClose)
 	t := time.NewTicker(100 * time.Millisecond)
 	defer t.Stop()
 	for {
@@ -586,7 +579,7 @@ func (c *Client) Close() error {
 	}
 	open := atomic.LoadUint64(&c.connCount)
 	if open > 0 {
-		mErr = append(mErr, fmt.Errorf("%d connection(s) still open after waiting %v", open, c.waitOnClose))
+		mErr = append(mErr, fmt.Errorf("%d connection(s) still open after waiting %v", open, c.conf.WaitOnClose))
 	}
 	if len(mErr) > 0 {
 		return mErr
@@ -619,8 +612,8 @@ func (c *Client) serveSocketMount(_ context.Context, s *socketMount) error {
 			count := atomic.AddUint64(&c.connCount, 1)
 			defer atomic.AddUint64(&c.connCount, ^uint64(0))
 
-			if c.maxConns > 0 && count > c.maxConns {
-				c.logger.Infof("max connections (%v) exceeded, refusing new connection", c.maxConns)
+			if c.conf.MaxConnections > 0 && count > c.conf.MaxConnections {
+				c.logger.Infof("max connections (%v) exceeded, refusing new connection", c.conf.MaxConnections)
 				_ = cConn.Close()
 				return
 			}

internal/proxy/proxy_other.go

@@ -116,7 +116,7 @@ func (c *Client) Lookup(ctx context.Context, instance string, _ *fuse.EntryOut)
 	}
 
 	s, err := newSocketMount(
-		ctx, &Config{UnixSocket: c.fuseTempDir},
+		ctx, withUnixSocket(*c.conf, c.fuseTempDir),
 		nil, InstanceConnConfig{Name: instanceURI},
 	)
 	if err != nil {
@@ -148,6 +148,11 @@ func (c *Client) Lookup(ctx context.Context, instance string, _ *fuse.EntryOut)
 	), fs.OK
 }
 
+func withUnixSocket(c Config, tmpDir string) *Config {
+	c.UnixSocket = tmpDir
+	return &c
+}
+
 func (c *Client) serveFuse(ctx context.Context, notify func()) error {
 	srv, err := fs.Mount(c.fuseDir, c, &fs.Options{
 		MountOptions: fuse.MountOptions{AllowOther: true},

tests/connection_test.go

@@ -70,6 +70,10 @@ func keyfile(t *testing.T) string {
 
 // proxyConnTest is a test helper to verify the proxy works with a basic connectivity test.
 func proxyConnTest(t *testing.T, args []string, driver, dsn string) {
+	proxyConnTestWithReady(t, args, driver, dsn, func() error { return nil })
+}
+
+func proxyConnTestWithReady(t *testing.T, args []string, driver, dsn string, ready func() error) {
 	ctx, cancel := context.WithTimeout(context.Background(), connTestTimeout)
 	defer cancel()
 	// Start the proxy
@@ -82,6 +86,9 @@ func proxyConnTest(t *testing.T, args []string, driver, dsn string) {
 	if err != nil {
 		t.Fatalf("unable to verify proxy was serving: %s \n %s", err, output)
 	}
+	if err := ready(); err != nil {
+		t.Fatalf("proxy was not ready: %v", err)
+	}
 
 	// Connect to the instance
 	db, err := sql.Open(driver, dsn)

tests/fuse_test.go

@@ -0,0 +1,82 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !windows && !darwin
+
+package tests
+
+import (
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/GoogleCloudPlatform/alloydb-auth-proxy/internal/proxy"
+)
+
+func TestPostgresFUSEConnect(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping Postgres integration tests")
+	}
+	_, isFlex := os.LookupEnv("FLEX")
+	if isFlex {
+		t.Skip("App Engine Flex doesn't support FUSE")
+	}
+	tmpDir, cleanup := createTempDir(t)
+	defer cleanup()
+
+	host := proxy.UnixAddress(tmpDir, *alloydbConnName)
+	dsn := fmt.Sprintf(
+		"host=%s user=%s password=%s database=%s sslmode=disable",
+		host, *alloydbUser, *alloydbPass, *alloydbDB,
+	)
+	testFUSE(t, tmpDir, host, dsn)
+}
+
+func testFUSE(t *testing.T, tmpDir, host string, dsn string) {
+	tmpDir2, cleanup2 := createTempDir(t)
+	defer cleanup2()
+
+	waitForFUSE := func() error {
+		var err error
+		for i := 0; i < 10; i++ {
+			_, err = os.Stat(host)
+			if err == nil {
+				return nil
+			}
+			time.Sleep(500 * time.Millisecond)
+		}
+		return fmt.Errorf("failed to find FUSE mounted Unix socket: %v", err)
+	}
+
+	tcs := []struct {
+		desc   string
+		dbUser string
+		args   []string
+	}{
+		{
+			desc: "using default fuse",
+			args: []string{fmt.Sprintf("--fuse=%s", tmpDir), fmt.Sprintf("--fuse-tmp-dir=%s", tmpDir2)},
+		},
+	}
+
+	for _, tc := range tcs {
+		t.Run(tc.desc, func(t *testing.T) {
+			proxyConnTestWithReady(t, tc.args, "pgx", dsn, waitForFUSE)
+			// given the kernel some time to unmount the fuse
+			time.Sleep(100 * time.Millisecond)
+		})
+	}
+
+}