feat: Resolve DSN from runtime in PG Proxy

backend/controller/controller.go

@@ -769,7 +769,8 @@ func (s *Service) GetModuleContext(ctx context.Context, req *connect.Request[ftl
 						continue
 					}
 					dbTypes[db.Name] = dbType
-					if db.Runtime != nil {
+					// TODO: Move the DSN resolution to the runtime once MySQL proxy is working
+					if db.Runtime != nil && dbType == modulecontext.DBTypeMySQL {
 						databases[db.Name] = modulecontext.Database{
 							DSN:    db.Runtime.DSN,
 							DBType: dbType,

backend/runner/runner.go

@@ -24,6 +24,7 @@ import (
 	"github.com/alecthomas/types/optional"
 	"github.com/jpillora/backoff"
 	"github.com/otiai10/copy"
+	"golang.org/x/sync/errgroup"
 	"google.golang.org/protobuf/types/known/structpb"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
@@ -39,6 +40,7 @@ import (
 	"github.com/TBD54566975/ftl/internal/log"
 	"github.com/TBD54566975/ftl/internal/model"
 	ftlobservability "github.com/TBD54566975/ftl/internal/observability"
+	"github.com/TBD54566975/ftl/internal/pgproxy"
 	"github.com/TBD54566975/ftl/internal/rpc"
 	"github.com/TBD54566975/ftl/internal/schema"
 	"github.com/TBD54566975/ftl/internal/slices"
@@ -129,7 +131,20 @@ func Start(ctx context.Context, config Config) error {
 		cancelFunc:         doneFunc,
 		devEndpoint:        config.DevEndpoint,
 	}
-	err = svc.deploy(ctx)
+
+	deploymentKey, err := model.ParseDeploymentKey(config.Deployment)
+	if err != nil {
+		observability.Deployment.Failure(ctx, optional.None[string]())
+		svc.cancelFunc()
+		return connect.NewError(connect.CodeInvalidArgument, fmt.Errorf("invalid deployment key: %w", err))
+	}
+
+	module, err := svc.getModule(ctx, deploymentKey)
+	if err != nil {
+		return fmt.Errorf("failed to get module: %w", err)
+	}
+
+	err = svc.deploy(ctx, deploymentKey, module)
 	if err != nil {
 		// If we fail to deploy we just exit
 		// Kube or local scaling will start a new instance to continue
@@ -143,11 +158,24 @@ func Start(ctx context.Context, config Config) error {
 		go rpc.RetryStreamingClientStream(ctx, backoff.Backoff{}, controllerClient.StreamDeploymentLogs, svc.streamLogsLoop)
 	}()
 
-	return rpc.Serve(ctx, config.Bind,
-		rpc.GRPC(ftlv1connect.NewVerbServiceHandler, svc),
-		rpc.HTTP("/", svc),
-		rpc.HealthCheck(svc.healthCheck),
-	)
+	pgProxyStarted := make(chan pgproxy.Started)
+
+	g, ctx := errgroup.WithContext(ctx)
+	g.Go(func() error {
+		return svc.startPgProxy(ctx, module, pgProxyStarted)
+	})
+	g.Go(func() error {
+		pgProxy := <-pgProxyStarted
+		os.Setenv("PG_PROXY_ADDRESS", fmt.Sprintf("127.0.0.1:%d", pgProxy.Address.Port))
+		logger.Debugf("PG_PROXY_ADDRESS: %s", os.Getenv("PG_PROXY_ADDRESS"))
+
+		return rpc.Serve(ctx, config.Bind,
+			rpc.GRPC(ftlv1connect.NewVerbServiceHandler, svc),
+			rpc.HTTP("/", svc),
+			rpc.HealthCheck(svc.healthCheck),
+		)
+	})
+	return fmt.Errorf("failure in runner: %w", g.Wait())
 }
 
 func newIdentityStore(ctx context.Context, config Config, key model.RunnerKey, controllerClient ftlv1connect.ControllerServiceClient) (*identity.Store, error) {
@@ -294,52 +322,51 @@ func (s *Service) Ping(ctx context.Context, req *connect.Request[ftlv1.PingReque
 	return connect.NewResponse(&ftlv1.PingResponse{}), nil
 }
 
-func (s *Service) deploy(ctx context.Context) error {
-	logger := log.FromContext(ctx)
-	if err, ok := s.registrationFailure.Load().Get(); ok {
-		observability.Deployment.Failure(ctx, optional.None[string]())
-		return connect.NewError(connect.CodeUnavailable, fmt.Errorf("failed to register runner: %w", err))
+func (s *Service) getModule(ctx context.Context, key model.DeploymentKey) (*schema.Module, error) {
+	gdResp, err := s.controllerClient.GetDeployment(ctx, connect.NewRequest(&ftlv1.GetDeploymentRequest{DeploymentKey: s.config.Deployment}))
+	if err != nil {
+		observability.Deployment.Failure(ctx, optional.Some(key.String()))
+		return nil, fmt.Errorf("failed to get deployment: %w", err)
 	}
 
-	key, err := model.ParseDeploymentKey(s.config.Deployment)
+	module, err := schema.ModuleFromProto(gdResp.Msg.Schema)
 	if err != nil {
+		observability.Deployment.Failure(ctx, optional.Some(key.String()))
+		return nil, fmt.Errorf("invalid module: %w", err)
+	}
+	return module, nil
+}
+
+func (s *Service) deploy(ctx context.Context, key model.DeploymentKey, module *schema.Module) error {
+	logger := log.FromContext(ctx)
+
+	if err, ok := s.registrationFailure.Load().Get(); ok {
 		observability.Deployment.Failure(ctx, optional.None[string]())
-		s.cancelFunc()
-		return connect.NewError(connect.CodeInvalidArgument, fmt.Errorf("invalid deployment key: %w", err))
+		return connect.NewError(connect.CodeUnavailable, fmt.Errorf("failed to register runner: %w", err))
 	}
 
 	observability.Deployment.Started(ctx, key.String())
 	defer observability.Deployment.Completed(ctx, key.String())
 
-	deploymentLogger := s.getDeploymentLogger(ctx, key)
-	ctx = log.ContextWithLogger(ctx, deploymentLogger)
-
 	s.lock.Lock()
 	defer s.lock.Unlock()
 	if s.deployment.Load().Ok() {
 		observability.Deployment.Failure(ctx, optional.Some(key.String()))
 		return errors.New("already deployed")
 	}
 
-	gdResp, err := s.controllerClient.GetDeployment(ctx, connect.NewRequest(&ftlv1.GetDeploymentRequest{DeploymentKey: s.config.Deployment}))
-	if err != nil {
-		observability.Deployment.Failure(ctx, optional.Some(key.String()))
-		return fmt.Errorf("failed to get deployment: %w", err)
-	}
-	module, err := schema.ModuleFromProto(gdResp.Msg.Schema)
-	if err != nil {
-		observability.Deployment.Failure(ctx, optional.Some(key.String()))
-		return fmt.Errorf("invalid module: %w", err)
-	}
+	deploymentLogger := s.getDeploymentLogger(ctx, key)
+	ctx = log.ContextWithLogger(ctx, deploymentLogger)
+
 	deploymentDir := filepath.Join(s.config.DeploymentDir, module.Name, key.String())
 	if s.config.TemplateDir != "" {
-		err = copy.Copy(s.config.TemplateDir, deploymentDir)
+		err := copy.Copy(s.config.TemplateDir, deploymentDir)
 		if err != nil {
 			observability.Deployment.Failure(ctx, optional.Some(key.String()))
 			return fmt.Errorf("failed to copy template directory: %w", err)
 		}
 	} else {
-		err = os.MkdirAll(deploymentDir, 0700)
+		err := os.MkdirAll(deploymentDir, 0700)
 		if err != nil {
 			observability.Deployment.Failure(ctx, optional.Some(key.String()))
 			return fmt.Errorf("failed to create deployment directory: %w", err)
@@ -377,7 +404,7 @@ func (s *Service) deploy(ctx context.Context) error {
 		deployment, cmdCtx, err := plugin.Spawn(
 			unstoppable.Context(verbCtx),
 			log.FromContext(ctx).GetLevel(),
-			gdResp.Msg.Schema.Name,
+			module.Name,
 			deploymentDir,
 			"./launch",
 			ftlv1connect.NewVerbServiceClient,
@@ -568,3 +595,27 @@ func (s *Service) healthCheck(writer http.ResponseWriter, request *http.Request)
 	}
 	writer.WriteHeader(http.StatusServiceUnavailable)
 }
+
+func (s *Service) startPgProxy(ctx context.Context, module *schema.Module, started chan<- pgproxy.Started) error {
+	logger := log.FromContext(ctx)
+
+	databases := map[string]*schema.Database{}
+	for _, decl := range module.Decls {
+		if db, ok := decl.(*schema.Database); ok {
+			databases[db.Name] = db
+		}
+	}
+
+	if err := pgproxy.New(":0", func(ctx context.Context, params map[string]string) (string, error) {
+		db, ok := databases[params["database"]]
+		if !ok {
+			return "", fmt.Errorf("database %s not found", params["database"])
+		}
+		logger.Debugf("Resolved DSN (%s): %s", params["database"], db.Runtime.DSN)
+
+		return db.Runtime.DSN, nil
+	}).Start(ctx, started); err != nil {
+		return fmt.Errorf("failed to start pgproxy: %w", err)
+	}
+	return nil
+}

cmd/ftl-proxy-pg/main.go

@@ -38,10 +38,10 @@ func main() {
 	err = observability.Init(ctx, false, "", "ftl-provisioner", ftl.Version, cli.ObservabilityConfig)
 	kctx.FatalIfErrorf(err, "failed to initialize observability")
 
-	proxy := pgproxy.New(cli.Config, func(ctx context.Context, params map[string]string) (string, error) {
+	proxy := pgproxy.New(cli.Config.Listen, func(ctx context.Context, params map[string]string) (string, error) {
 		return "postgres://localhost:5432/postgres?user=" + params["user"], nil
 	})
-	if err := proxy.Start(ctx); err != nil {
+	if err := proxy.Start(ctx, nil); err != nil {
 		kctx.FatalIfErrorf(err, "failed to start proxy")
 	}
 }

cmd/ftl-runner/main.go

@@ -2,25 +2,21 @@ package main
 
 import (
 	"context"
-	"fmt"
 	"os"
 	"path/filepath"
 
 	"github.com/alecthomas/kong"
-	"golang.org/x/sync/errgroup"
 
 	"github.com/TBD54566975/ftl"
 	"github.com/TBD54566975/ftl/backend/runner"
 	_ "github.com/TBD54566975/ftl/internal/automaxprocs" // Set GOMAXPROCS to match Linux container CPU quota.
 	"github.com/TBD54566975/ftl/internal/log"
-	"github.com/TBD54566975/ftl/internal/pgproxy"
 )
 
 var cli struct {
 	Version      kong.VersionFlag `help:"Show version."`
 	LogConfig    log.Config       `prefix:"log-" embed:""`
 	RunnerConfig runner.Config    `embed:""`
-	ProxyConfig  pgproxy.Config   `embed:"" prefix:"pgproxy-"`
 }
 
 func main() {
@@ -47,21 +43,5 @@ and route to user code.
 	logger := log.Configure(os.Stderr, cli.LogConfig)
 	ctx := log.ContextWithLogger(context.Background(), logger)
 
-	g, ctx := errgroup.WithContext(ctx)
-	g.Go(func() error {
-		return runPGProxy(ctx, cli.ProxyConfig)
-	})
-	g.Go(func() error {
-		return runner.Start(ctx, cli.RunnerConfig)
-	})
-	kctx.FatalIfErrorf(g.Wait())
-}
-
-func runPGProxy(ctx context.Context, config pgproxy.Config) error {
-	if err := pgproxy.New(config, func(ctx context.Context, params map[string]string) (string, error) {
-		return "postgres://127.0.0.1:5432/postgres?user=" + params["user"], nil
-	}).Start(ctx); err != nil {
-		return fmt.Errorf("failed to start pgproxy: %w", err)
-	}
-	return nil
+	kctx.FatalIfErrorf(runner.Start(ctx, cli.RunnerConfig))
 }

internal/modulecontext/module_context.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"os"
 	"strings"
 	"sync"
 	"time"
@@ -159,6 +160,10 @@ func (m ModuleContext) GetSecret(name string, value any) error {
 func (m ModuleContext) GetDatabase(name string, dbType DBType) (string, bool, error) {
 	db, ok := m.databases[name]
 	if !ok {
+		if dbType == DBTypePostgres {
+			proxyAddress := os.Getenv("PG_PROXY_ADDRESS")
+			return "postgres://" + proxyAddress + "/" + name, false, nil
+		}
 		return "", false, fmt.Errorf("missing DSN for database %s", name)
 	}
 	if db.DBType != dbType {

internal/pgproxy/pgproxy.go

@@ -30,15 +30,19 @@ type DSNConstructor func(ctx context.Context, params map[string]string) (string,
 //
 // address is the address to listen on for incoming connections.
 // connectionFn is a function that constructs a new connection string from parameters of the incoming connection.
-func New(config Config, connectionFn DSNConstructor) *PgProxy {
+func New(listenAddress string, connectionFn DSNConstructor) *PgProxy {
 	return &PgProxy{
-		listenAddress:      config.Listen,
+		listenAddress:      listenAddress,
 		connectionStringFn: connectionFn,
 	}
 }
 
-// Start the proxy.
-func (p *PgProxy) Start(ctx context.Context) error {
+type Started struct {
+	Address *net.TCPAddr
+}
+
+// Start the proxy
+func (p *PgProxy) Start(ctx context.Context, started chan<- Started) error {
 	logger := log.FromContext(ctx)
 
 	listener, err := net.Listen("tcp", p.listenAddress)
@@ -47,6 +51,14 @@ func (p *PgProxy) Start(ctx context.Context) error {
 	}
 	defer listener.Close()
 
+	if started != nil {
+		addr, ok := listener.Addr().(*net.TCPAddr)
+		if !ok {
+			panic("failed to get TCP address")
+		}
+		started <- Started{Address: addr}
+	}
+
 	for {
 		conn, err := listener.Accept()
 		if err != nil {