watcher: Detect 'terraform init' from scratch

This is a bigger change than perhaps expected but I was not able to come up with any decent way of splitting it up.

As mentioned in one in-line comment, there is currently no reliable and efficient way of watching a directory *recursively* in Go. There are some alternative solutions, but they either involve cgo or don't actually use any "event API" of the underlying OS but repeatedly do filewalk.

Previously we watched individual manifest and lock file of a module and we can't watch for *creation* of these files in a directory which doesn't exist yet. Therefore it was decided to instead watch the relevant parent directories and add relevant nested directories on creation and/or walk the hierarchy of the newly created dir. This creates even more places from where parts of module can be (re)loaded (walker, watcher, handlers), which would be hard to accommodate in the old design.

Therefore a mechanism for queueing all module operations was created.

This allows for a naive deduplication of operations (we don't run the same operation on the same module if it's already queued) and also allows us to report progress more easily in the future.

Finally this design also allows any caller to decide whether run an operation synchronously or asynchronously. e.g. We can wait for a module to be parsed in textDocument/didChange handler.

internal/cmd/completion_command.go

@@ -102,21 +102,27 @@ func (c *CompletionCommand) Run(args []string) int {
 		return 1
 	}
 
-	module, err := module.NewModule(context.Background(), fs, fh.Dir())
+	ctx := context.Background()
+	modMgr := module.NewSyncModuleManager(ctx, fs)
+
+	mod, err := modMgr.AddModule(fh.Dir())
 	if err != nil {
-		c.Ui.Error(fmt.Sprintf("failed to load module: %s", err.Error()))
+		c.Ui.Error(err.Error())
 		return 1
 	}
-	schema, err := module.MergedSchema()
+
+	schema, err := modMgr.SchemaForModule(fh.Dir())
 	if err != nil {
 		c.Ui.Error(fmt.Sprintf("failed to find schema: %s", err.Error()))
 		return 1
 	}
-	d, err := module.DecoderWithSchema(schema)
+
+	d, err := module.DecoderForModule(mod)
 	if err != nil {
-		c.Ui.Error(fmt.Sprintf("failed to find parser: %s", err.Error()))
+		c.Ui.Error(fmt.Sprintf("failed to find decoder: %s", err.Error()))
 		return 1
 	}
+	d.SetSchema(schema)
 
 	pos := fPos.Position()
 

internal/cmd/inspect_module_command.go

@@ -16,6 +16,7 @@ import (
 	ictx "github.com/hashicorp/terraform-ls/internal/context"
 	"github.com/hashicorp/terraform-ls/internal/filesystem"
 	"github.com/hashicorp/terraform-ls/internal/logging"
+	"github.com/hashicorp/terraform-ls/internal/terraform/datadir"
 	"github.com/hashicorp/terraform-ls/internal/terraform/module"
 	"github.com/mitchellh/cli"
 )
@@ -84,46 +85,50 @@ func (c *InspectModuleCommand) inspect(rootPath string) error {
 
 	fs := filesystem.NewFilesystem()
 
-	modMgr := module.NewModuleManager(fs)
+	ctx := context.Background()
+	modMgr := module.NewSyncModuleManager(ctx, fs)
 	modMgr.SetLogger(c.logger)
-	walker := module.NewWalker()
+
+	walker := module.SyncWalker(fs, modMgr)
 	walker.SetLogger(c.logger)
 
 	ctx, cancel := ictx.WithSignalCancel(context.Background(),
 		c.logger, syscall.SIGINT, syscall.SIGTERM)
 	defer cancel()
 
-	err = walker.StartWalking(ctx, rootPath, func(ctx context.Context, dir string) error {
-		mod, err := modMgr.AddAndStartLoadingModule(ctx, dir)
-		if err != nil {
-			return err
-		}
-		<-mod.LoadingDone()
-
-		return nil
-	})
+	err = walker.StartWalking(ctx, rootPath)
 	if err != nil {
 		return err
 	}
 
-	<-walker.Done()
-
 	modules := modMgr.ListModules()
 	c.Ui.Output(fmt.Sprintf("%d modules found in total at %s", len(modules), rootPath))
 	for _, mod := range modules {
 		errs := &multierror.Error{}
 
-		err := mod.LoadError()
+		_, err = mod.TerraformVersion()
 		if err != nil {
-			var ok bool
-			errs, ok = err.(*multierror.Error)
-			if !ok {
-				return err
-			}
+			multierror.Append(errs, err)
+		}
+
+		_, err := mod.ProviderSchema()
+		if err != nil {
+			multierror.Append(errs, err)
+		}
+
+		_, err = mod.ModuleManifest()
+		if err != nil {
+			multierror.Append(errs, err)
 		}
+
+		_, err = mod.ParsedFiles()
+		if err != nil {
+			multierror.Append(errs, err)
+		}
+
 		errs.ErrorFormat = formatErrors
 
-		modules := formatModuleRecords(mod.Modules())
+		modules := formatModuleRecords(mod.ModuleCalls())
 		subModules := fmt.Sprintf("%d modules", len(modules))
 		if len(modules) > 0 {
 			subModules += "\n"
@@ -153,7 +158,7 @@ func formatErrors(errors []error) string {
 	return strings.TrimSpace(out)
 }
 
-func formatModuleRecords(mds []module.ModuleRecord) []string {
+func formatModuleRecords(mds []datadir.ModuleRecord) []string {
 	out := make([]string, 0)
 	for _, m := range mds {
 		if m.IsRoot() {

internal/context/context.go

@@ -9,7 +9,6 @@ import (
 	lsp "github.com/hashicorp/terraform-ls/internal/protocol"
 	"github.com/hashicorp/terraform-ls/internal/settings"
 	"github.com/hashicorp/terraform-ls/internal/terraform/module"
-	"github.com/hashicorp/terraform-ls/internal/watcher"
 )
 
 type contextKey struct {
@@ -29,10 +28,8 @@ var (
 	ctxTfExecTimeout        = &contextKey{"terraform execution timeout"}
 	ctxWatcher              = &contextKey{"watcher"}
 	ctxModuleMngr           = &contextKey{"module manager"}
-	ctxTfFormatterFinder    = &contextKey{"terraform formatter finder"}
-	ctxModuleCaFi           = &contextKey{"module candidate finder"}
+	ctxModuleFinder         = &contextKey{"module finder"}
 	ctxModuleWalker         = &contextKey{"module walker"}
-	ctxModuleLoader         = &contextKey{"module loader"}
 	ctxRootDir              = &contextKey{"root directory"}
 	ctxCommandPrefix        = &contextKey{"command prefix"}
 	ctxDiags                = &contextKey{"diagnostics"}
@@ -103,12 +100,12 @@ func TerraformExecTimeout(ctx context.Context) (time.Duration, bool) {
 	return path, ok
 }
 
-func WithWatcher(ctx context.Context, w watcher.Watcher) context.Context {
+func WithWatcher(ctx context.Context, w module.Watcher) context.Context {
 	return context.WithValue(ctx, ctxWatcher, w)
 }
 
-func Watcher(ctx context.Context) (watcher.Watcher, error) {
-	w, ok := ctx.Value(ctxWatcher).(watcher.Watcher)
+func Watcher(ctx context.Context) (module.Watcher, error) {
+	w, ok := ctx.Value(ctxWatcher).(module.Watcher)
 	if !ok {
 		return nil, missingContextErr(ctxWatcher)
 	}
@@ -127,18 +124,6 @@ func ModuleManager(ctx context.Context) (module.ModuleManager, error) {
 	return wm, nil
 }
 
-func WithTerraformFormatterFinder(ctx context.Context, tef module.TerraformFormatterFinder) context.Context {
-	return context.WithValue(ctx, ctxTfFormatterFinder, tef)
-}
-
-func TerraformFormatterFinder(ctx context.Context) (module.TerraformFormatterFinder, error) {
-	pf, ok := ctx.Value(ctxTfFormatterFinder).(module.TerraformFormatterFinder)
-	if !ok {
-		return nil, missingContextErr(ctxTfFormatterFinder)
-	}
-	return pf, nil
-}
-
 func WithTerraformExecPath(ctx context.Context, path string) context.Context {
 	return context.WithValue(ctx, ctxTfExecPath, path)
 }
@@ -149,13 +134,13 @@ func TerraformExecPath(ctx context.Context) (string, bool) {
 }
 
 func WithModuleFinder(ctx context.Context, mf module.ModuleFinder) context.Context {
-	return context.WithValue(ctx, ctxModuleCaFi, mf)
+	return context.WithValue(ctx, ctxModuleFinder, mf)
 }
 
 func ModuleFinder(ctx context.Context) (module.ModuleFinder, error) {
-	cf, ok := ctx.Value(ctxModuleCaFi).(module.ModuleFinder)
+	cf, ok := ctx.Value(ctxModuleFinder).(module.ModuleFinder)
 	if !ok {
-		return nil, missingContextErr(ctxModuleCaFi)
+		return nil, missingContextErr(ctxModuleFinder)
 	}
 	return cf, nil
 }
@@ -216,18 +201,6 @@ func ModuleWalker(ctx context.Context) (*module.Walker, error) {
 	return w, nil
 }
 
-func WithModuleLoader(ctx context.Context, ml module.ModuleLoader) context.Context {
-	return context.WithValue(ctx, ctxModuleLoader, ml)
-}
-
-func ModuleLoader(ctx context.Context) (module.ModuleLoader, error) {
-	w, ok := ctx.Value(ctxModuleLoader).(module.ModuleLoader)
-	if !ok {
-		return nil, missingContextErr(ctxModuleLoader)
-	}
-	return w, nil
-}
-
 func WithDiagnostics(ctx context.Context, diags *diagnostics.Notifier) context.Context {
 	return context.WithValue(ctx, ctxDiags, diags)
 }

internal/filesystem/filesystem.go

@@ -2,6 +2,7 @@ package filesystem
 
 import (
 	"bytes"
+	"fmt"
 	"io/ioutil"
 	"log"
 	"os"
@@ -36,6 +37,18 @@ func (fs *fsystem) SetLogger(logger *log.Logger) {
 }
 
 func (fs *fsystem) CreateDocument(dh DocumentHandler, text []byte) error {
+	_, err := fs.memFs.Stat(dh.Dir())
+	if err != nil {
+		if os.IsNotExist(err) {
+			err := fs.memFs.MkdirAll(dh.Dir(), 0755)
+			if err != nil {
+				return fmt.Errorf("failed to create parent dir: %w", err)
+			}
+		} else {
+			return err
+		}
+	}
+
 	f, err := fs.memFs.Create(dh.FullPath())
 	if err != nil {
 		return err
@@ -196,11 +209,11 @@ func (fs *fsystem) ReadFile(name string) ([]byte, error) {
 func (fs *fsystem) ReadDir(name string) ([]os.FileInfo, error) {
 	memList, err := afero.ReadDir(fs.memFs, name)
 	if err != nil && !os.IsNotExist(err) {
-		return nil, err
+		return nil, fmt.Errorf("memory FS: %w", err)
 	}
 	osList, err := afero.ReadDir(fs.osFs, name)
-	if err != nil {
-		return nil, err
+	if err != nil && !os.IsNotExist(err) {
+		return nil, fmt.Errorf("OS FS: %w", err)
 	}
 
 	list := memList

internal/filesystem/filesystem_metadata.go

@@ -1,7 +1,10 @@
 package filesystem
 
 import (
+	"path/filepath"
+
 	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/terraform-ls/internal/uri"
 )
 
 func (fs *fsystem) markDocumentAsOpen(dh DocumentHandler) error {
@@ -16,6 +19,26 @@ func (fs *fsystem) markDocumentAsOpen(dh DocumentHandler) error {
 	return nil
 }
 
+func (fs *fsystem) HasOpenFiles(dirPath string) (bool, error) {
+	files, err := fs.ReadDir(dirPath)
+	if err != nil {
+		return false, err
+	}
+
+	fs.docMetaMu.RLock()
+	defer fs.docMetaMu.RUnlock()
+
+	for _, fi := range files {
+		u := uri.FromPath(filepath.Join(dirPath, fi.Name()))
+		dm, ok := fs.docMeta[u]
+		if ok && dm.IsOpen() {
+			return true, nil
+		}
+	}
+
+	return false, nil
+}
+
 func (fs *fsystem) createDocumentMetadata(dh DocumentHandler, text []byte) error {
 	if fs.documentMetadataExists(dh) {
 		return &MetadataAlreadyExistsErr{dh}