feat: add LSP for FTL

Add an LSP that produces document highlights when FTL outputs build errors

this is a work in progress

buildengine/engine.go

@@ -22,6 +22,7 @@ import (
 	"github.com/TBD54566975/ftl/backend/schema"
 	"github.com/TBD54566975/ftl/internal/log"
 	"github.com/TBD54566975/ftl/internal/rpc"
+	"github.com/TBD54566975/ftl/lsp"
 )
 
 type schemaChange struct {
@@ -190,22 +191,23 @@ func (e *Engine) Deploy(ctx context.Context, replicas int32, waitForDeployOnline
 }
 
 // Dev builds and deploys all local modules and watches for changes, redeploying as necessary.
-func (e *Engine) Dev(ctx context.Context, period time.Duration) error {
+func (e *Engine) Dev(ctx context.Context, period time.Duration, languageServer *lsp.Server) error {
 	logger := log.FromContext(ctx)
 
 	// Build and deploy all modules first.
 	err := e.buildAndDeploy(ctx, 1, true)
 	if err != nil {
 		logger.Errorf(err, "initial deploy failed")
+		languageServer.Post(err)
 	}
 
 	logger.Infof("All modules deployed, watching for changes...")
 
 	// Then watch for changes and redeploy.
-	return e.watchForModuleChanges(ctx, period)
+	return e.watchForModuleChanges(ctx, period, languageServer)
 }
 
-func (e *Engine) watchForModuleChanges(ctx context.Context, period time.Duration) error {
+func (e *Engine) watchForModuleChanges(ctx context.Context, period time.Duration, languageServer *lsp.Server) error {
 	logger := log.FromContext(ctx)
 
 	moduleHashes := map[string][]byte{}
@@ -243,6 +245,7 @@ func (e *Engine) watchForModuleChanges(ctx context.Context, period time.Duration
 					err := e.buildAndDeploy(ctx, 1, true, config.Key)
 					if err != nil {
 						logger.Errorf(err, "deploy %s failed", config.Key)
+						languageServer.Post(err)
 					}
 				}
 			case WatchEventProjectRemoved:
@@ -258,6 +261,7 @@ func (e *Engine) watchForModuleChanges(ctx context.Context, period time.Duration
 				config := event.Project.Config()
 				err := e.buildAndDeploy(ctx, 1, true, config.Key)
 				if err != nil {
+					languageServer.Post(err)
 					switch project := event.Project.(type) {
 					case Module:
 						logger.Errorf(err, "build and deploy failed for module %q: %v", project.Config().Key, err)

cmd/ftl/cmd_dev.go

@@ -11,6 +11,7 @@ import (
 	"github.com/TBD54566975/ftl/buildengine"
 	"github.com/TBD54566975/ftl/common/projectconfig"
 	"github.com/TBD54566975/ftl/internal/rpc"
+	"github.com/TBD54566975/ftl/lsp"
 )
 
 type devCmd struct {
@@ -52,6 +53,11 @@ func (d *devCmd) Run(ctx context.Context, projConfig projectconfig.Config) error
 		})
 	}
 
+	languageServer := lsp.NewServer(ctx)
+	g.Go(func() error {
+		return languageServer.Run()
+	})
+
 	err := d.ServeCmd.pollControllerOnine(ctx, client)
 	if err != nil {
 		return err
@@ -62,7 +68,7 @@ func (d *devCmd) Run(ctx context.Context, projConfig projectconfig.Config) error
 		if err != nil {
 			return err
 		}
-		return engine.Dev(ctx, d.Watch)
+		return engine.Dev(ctx, d.Watch, languageServer)
 	})
 
 	return g.Wait()

examples/go/echo/echo.go

@@ -32,16 +32,3 @@ func Echo(ctx context.Context, req EchoRequest) (EchoResponse, error) {
 
 	return EchoResponse{Message: fmt.Sprintf("Hello, %s!!! It is %s!", req.Name.Default(defaultName.Get(ctx)), tresp.Time)}, nil
 }
-
-/*
-
-verb cronJob(Unit) Unit
-	+cron "0 0 * * *"
-
-*/
-
-//ftl:cron <schedule>
-func CronJob(ctx context.Context) error {
-	_, err := ftl.Call(ctx, Echo, EchoRequest{})
-	return err
-}

go.mod

@@ -30,11 +30,15 @@ require (
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51
 	github.com/mattn/go-isatty v0.0.20
 	github.com/otiai10/copy v1.14.0
+	github.com/pkg/errors v0.9.1
 	github.com/radovskyb/watcher v1.0.7
 	github.com/rs/cors v1.10.1
 	github.com/santhosh-tekuri/jsonschema/v5 v5.3.1
 	github.com/swaggest/jsonschema-go v0.3.69
 	github.com/titanous/json5 v1.0.0
+	github.com/tliron/commonlog v0.2.16
+	github.com/tliron/glsp v0.2.2
+	github.com/tliron/kutil v0.3.24
 	github.com/tmc/langchaingo v0.1.5
 	github.com/zalando/go-keyring v0.2.3
 	go.opentelemetry.io/otel v1.24.0
@@ -56,10 +60,21 @@ require (
 )
 
 require (
+	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
+	github.com/gorilla/websocket v1.5.1 // indirect
 	github.com/hashicorp/golang-lru/v2 v2.0.7 // indirect
+	github.com/iancoleman/strcase v0.3.0 // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-runewidth v0.0.14 // indirect
+	github.com/muesli/termenv v0.15.2 // indirect
 	github.com/ncruces/go-strftime v0.1.9 // indirect
+	github.com/petermattis/goid v0.0.0-20180202154549-b0b1615b78e5 // indirect
 	github.com/pkoukk/tiktoken-go v0.1.2 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	github.com/sasha-s/go-deadlock v0.3.1 // indirect
+	github.com/segmentio/ksuid v1.0.4 // indirect
+	github.com/sourcegraph/jsonrpc2 v0.2.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.1.0 // indirect
 	modernc.org/gc/v3 v3.0.0-20240107210532-573471604cb6 // indirect
 )

kotlin-runtime/scaffolding/{{ .Name | lower }}/pom.xml

@@ -1,7 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xmlns="http://maven.apache.org/POM/4.0.0"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
     <groupId>{{ .GroupID }}</groupId>

lsp/logger.go

@@ -0,0 +1,67 @@
+package lsp
+
+import (
+	"fmt"
+
+	"github.com/tliron/commonlog"
+
+	"github.com/TBD54566975/ftl/internal/log"
+)
+
+// GLSPLogger is a custom logger for the language server.
+type GLSPLogger struct {
+	commonlog.Logger
+}
+
+func (l *GLSPLogger) Log(entry log.Entry) {
+	l.Logger.Log(toGLSPLevel(entry.Level), 10, entry.Message, entry.Attributes)
+}
+
+func (l *GLSPLogger) Logf(level log.Level, format string, args ...interface{}) {
+	l.Log(log.Entry{Level: level, Message: fmt.Sprintf(format, args...)})
+}
+func (l *GLSPLogger) Tracef(format string, args ...interface{}) {
+	l.Log(log.Entry{Level: log.Trace, Message: fmt.Sprintf(format, args...)})
+}
+
+func (l *GLSPLogger) Debugf(format string, args ...interface{}) {
+	l.Log(log.Entry{Level: log.Debug, Message: fmt.Sprintf(format, args...)})
+}
+
+func (l *GLSPLogger) Infof(format string, args ...interface{}) {
+	l.Log(log.Entry{Level: log.Info, Message: fmt.Sprintf(format, args...)})
+}
+
+func (l *GLSPLogger) Warnf(format string, args ...interface{}) {
+	l.Log(log.Entry{Level: log.Warn, Message: fmt.Sprintf(format, args...)})
+}
+
+func (l *GLSPLogger) Errorf(err error, format string, args ...interface{}) {
+	if err == nil {
+		return
+	}
+	l.Log(log.Entry{Level: log.Error, Message: fmt.Sprintf(format, args...) + ": " + err.Error(), Error: err})
+}
+
+var _ log.Interface = (*GLSPLogger)(nil)
+
+func NewGLSPLogger(log commonlog.Logger) *GLSPLogger {
+	return &GLSPLogger{log}
+}
+
+func toGLSPLevel(l log.Level) commonlog.Level {
+	switch l {
+	case log.Trace:
+		return commonlog.Debug
+	case log.Debug:
+		return commonlog.Debug
+	case log.Info:
+		return commonlog.Info
+	case log.Warn:
+		return commonlog.Warning
+	case log.Error:
+		return commonlog.Error
+	default:
+		return commonlog.Debug
+	}
+}