Refactor job scheduler to use memdb for jobs (#782)

* internal/job: Introduce Job & related types

* internal/state: Introduce new 'jobs' table

* internal/scheduler: Introduce general-purpose job scheduler

* internal/terraform/module(watcher+walker): Update references

* internal/langserver/handlers: Update references

* internal/terraform/module: Remove module manager & loader & queue

* internal/terraform/module: Repurpose old mod mgr test cases

In the old test we would be checking what *all* schemas are available for a given path after indexing via walker.

This part of API is however being deprecated in favour of more straightforward one (see state.ProviderSchemaStore -> ProviderSchema()) which picks the single most appropriate schema from a list of candidates and retains the decision logic as an implementation detail within it, so the whole list of candidates is not really available from the outside (by design), hence not something we should test from the outside.

ProviderSchemaStore itself already has plenty of tests testing the decision logic within, which is better place for testing this anyway.

* jobs benchmarks

internal/cmd/completion_command.go

@@ -18,7 +18,6 @@ import (
 	ilsp "github.com/hashicorp/terraform-ls/internal/lsp"
 	lsp "github.com/hashicorp/terraform-ls/internal/protocol"
 	"github.com/hashicorp/terraform-ls/internal/state"
-	"github.com/hashicorp/terraform-ls/internal/terraform/module"
 	"github.com/mitchellh/cli"
 )
 
@@ -113,9 +112,7 @@ func (c *CompletionCommand) Run(args []string) int {
 
 	ctx := context.Background()
 
-	modMgr := module.NewSyncModuleManager(ctx, fs, ss.DocumentStore, ss.Modules, ss.ProviderSchemas)
-
-	_, err = modMgr.AddModule(dh.Dir.Path())
+	err = ss.Modules.Add(dh.Dir.Path())
 	if err != nil {
 		c.Ui.Error(err.Error())
 		return 1

internal/cmd/inspect_module_command.go

@@ -18,6 +18,7 @@ import (
 	"github.com/hashicorp/terraform-ls/internal/logging"
 	"github.com/hashicorp/terraform-ls/internal/state"
 	"github.com/hashicorp/terraform-ls/internal/terraform/datadir"
+	"github.com/hashicorp/terraform-ls/internal/terraform/exec"
 	"github.com/hashicorp/terraform-ls/internal/terraform/module"
 	"github.com/mitchellh/cli"
 )
@@ -93,10 +94,7 @@ func (c *InspectModuleCommand) inspect(rootPath string) error {
 
 	ctx := context.Background()
 
-	modMgr := module.NewSyncModuleManager(ctx, fs, ss.DocumentStore, ss.Modules, ss.ProviderSchemas)
-	modMgr.SetLogger(c.logger)
-
-	walker := module.SyncWalker(fs, ss.DocumentStore, modMgr)
+	walker := module.SyncWalker(fs, ss.DocumentStore, ss.Modules, ss.ProviderSchemas, ss.JobStore, exec.NewExecutor)
 	walker.SetLogger(c.logger)
 
 	ctx, cancel := ictx.WithSignalCancel(context.Background(),
@@ -109,7 +107,7 @@ func (c *InspectModuleCommand) inspect(rootPath string) error {
 		return err
 	}
 
-	modules, err := modMgr.ListModules()
+	modules, err := ss.Modules.List()
 	if err != nil {
 		return err
 	}

internal/context/context.go

@@ -23,8 +23,6 @@ var (
 	ctxTfExecLogPath        = &contextKey{"terraform executor log path"}
 	ctxTfExecTimeout        = &contextKey{"terraform execution timeout"}
 	ctxWatcher              = &contextKey{"watcher"}
-	ctxModuleMngr           = &contextKey{"module manager"}
-	ctxModuleFinder         = &contextKey{"module finder"}
 	ctxModuleWalker         = &contextKey{"module walker"}
 	ctxRootDir              = &contextKey{"root directory"}
 	ctxCommandPrefix        = &contextKey{"command prefix"}
@@ -68,18 +66,6 @@ func Watcher(ctx context.Context) (module.Watcher, error) {
 	return w, nil
 }
 
-func WithModuleManager(ctx context.Context, wm module.ModuleManager) context.Context {
-	return context.WithValue(ctx, ctxModuleMngr, wm)
-}
-
-func ModuleManager(ctx context.Context) (module.ModuleManager, error) {
-	wm, ok := ctx.Value(ctxModuleMngr).(module.ModuleManager)
-	if !ok {
-		return nil, missingContextErr(ctxModuleMngr)
-	}
-	return wm, nil
-}
-
 func WithTerraformExecPath(ctx context.Context, path string) context.Context {
 	return context.WithValue(ctx, ctxTfExecPath, path)
 }
@@ -89,18 +75,6 @@ func TerraformExecPath(ctx context.Context) (string, bool) {
 	return path, ok
 }
 
-func WithModuleFinder(ctx context.Context, mf module.ModuleFinder) context.Context {
-	return context.WithValue(ctx, ctxModuleFinder, mf)
-}
-
-func ModuleFinder(ctx context.Context) (module.ModuleFinder, error) {
-	cf, ok := ctx.Value(ctxModuleFinder).(module.ModuleFinder)
-	if !ok {
-		return nil, missingContextErr(ctxModuleFinder)
-	}
-	return cf, nil
-}
-
 func WithRootDirectory(ctx context.Context, dir *string) context.Context {
 	return context.WithValue(ctx, ctxRootDir, dir)
 }

internal/job/job.go

@@ -0,0 +1,40 @@
+package job
+
+import (
+	"context"
+
+	"github.com/hashicorp/terraform-ls/internal/document"
+)
+
+type Job struct {
+	// Func represents the job to execute
+	Func func(ctx context.Context) error
+
+	// Dir describes the directory which the job belongs to,
+	// which is used for deduplication of queued jobs (along with Type)
+	// and prioritization
+	Dir document.DirHandle
+
+	// Type describes type of the job (e.g. GetTerraformVersion),
+	// which is used for deduplication of queued jobs along with Dir.
+	Type string
+
+	// Defer is a function to execute after Func is executed
+	// and before the job is marked as done (StateDone).
+	// This can be used to schedule jobs dependent on the main job.
+	Defer DeferFunc
+}
+
+// DeferFunc represents a deferred function scheduling more jobs
+// based on jobErr (any error returned from the main job).
+// Newly queued job IDs should be returned to allow for synchronization.
+type DeferFunc func(ctx context.Context, jobErr error) IDs
+
+func (job Job) Copy() Job {
+	return Job{
+		Func:  job.Func,
+		Dir:   job.Dir,
+		Type:  job.Type,
+		Defer: job.Defer,
+	}
+}

internal/job/job_id.go

@@ -0,0 +1,19 @@
+package job
+
+type ID string
+
+func (id ID) String() string {
+	return string(id)
+}
+
+type IDs []ID
+
+func (ids IDs) Copy() IDs {
+	newIds := make([]ID, len(ids))
+
+	for i, id := range ids {
+		newIds[i] = id
+	}
+
+	return newIds
+}

internal/job/job_store.go

@@ -0,0 +1,25 @@
+package job
+
+import (
+	"context"
+	"fmt"
+)
+
+type JobStore interface {
+	EnqueueJob(newJob Job) (ID, error)
+	WaitForJobs(ctx context.Context, ids ...ID) error
+}
+
+type jobStoreCtxKey struct{}
+
+func WithJobStore(ctx context.Context, js JobStore) context.Context {
+	return context.WithValue(ctx, jobStoreCtxKey{}, js)
+}
+
+func JobStoreFromContext(ctx context.Context) (JobStore, error) {
+	js, ok := ctx.Value(jobStoreCtxKey{}).(JobStore)
+	if !ok {
+		return nil, fmt.Errorf("not found JobStore in context")
+	}
+	return js, nil
+}

internal/langserver/handlers/code_lens_test.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"path/filepath"
 	"testing"
-	"time"
 
 	"github.com/hashicorp/go-version"
 	tfjson "github.com/hashicorp/terraform-json"
@@ -262,9 +261,6 @@ variable "instances" {
   type = number
 }
 `, submodUri.URI)})
-	// TODO remove once we support synchronous dependent tasks
-	// See https://github.com/hashicorp/terraform-ls/issues/719
-	time.Sleep(2 * time.Second)
 	ls.CallAndExpectResponse(t, &langserver.CallRequest{
 		Method: "textDocument/codeLens",
 		ReqParams: fmt.Sprintf(`{

internal/langserver/handlers/command/handler.go

@@ -0,0 +1,7 @@
+package command
+
+import "github.com/hashicorp/terraform-ls/internal/state"
+
+type CmdHandler struct {
+	StateStore *state.StateStore
+}

internal/langserver/handlers/command/init.go

@@ -5,16 +5,16 @@ import (
 	"fmt"
 
 	"github.com/creachadair/jrpc2/code"
-	lsctx "github.com/hashicorp/terraform-ls/internal/context"
 	"github.com/hashicorp/terraform-ls/internal/document"
 	"github.com/hashicorp/terraform-ls/internal/langserver/cmd"
 	"github.com/hashicorp/terraform-ls/internal/langserver/errors"
 	"github.com/hashicorp/terraform-ls/internal/langserver/progress"
+	"github.com/hashicorp/terraform-ls/internal/state"
 	"github.com/hashicorp/terraform-ls/internal/terraform/module"
 	"github.com/hashicorp/terraform-ls/internal/uri"
 )
 
-func TerraformInitHandler(ctx context.Context, args cmd.CommandArgs) (interface{}, error) {
+func (h *CmdHandler) TerraformInitHandler(ctx context.Context, args cmd.CommandArgs) (interface{}, error) {
 	dirUri, ok := args.GetString("uri")
 	if !ok || dirUri == "" {
 		return nil, fmt.Errorf("%w: expected module uri argument to be set", code.InvalidParams.Err())
@@ -26,15 +26,14 @@ func TerraformInitHandler(ctx context.Context, args cmd.CommandArgs) (interface{
 
 	dirHandle := document.DirHandleFromURI(dirUri)
 
-	modMgr, err := lsctx.ModuleManager(ctx)
+	mod, err := h.StateStore.Modules.ModuleByPath(dirHandle.Path())
 	if err != nil {
-		return nil, err
-	}
-
-	mod, err := modMgr.ModuleByPath(dirHandle.Path())
-	if err != nil {
-		if module.IsModuleNotFound(err) {
-			mod, err = modMgr.AddModule(dirHandle.Path())
+		if state.IsModuleNotFound(err) {
+			err = h.StateStore.Modules.Add(dirHandle.Path())
+			if err != nil {
+				return nil, err
+			}
+			mod, err = h.StateStore.Modules.ModuleByPath(dirHandle.Path())
 			if err != nil {
 				return nil, err
 			}

internal/langserver/handlers/command/module_callers.go

@@ -6,7 +6,6 @@ import (
 	"sort"
 
 	"github.com/creachadair/jrpc2/code"
-	lsctx "github.com/hashicorp/terraform-ls/internal/context"
 	"github.com/hashicorp/terraform-ls/internal/langserver/cmd"
 	"github.com/hashicorp/terraform-ls/internal/uri"
 )
@@ -22,7 +21,7 @@ type moduleCaller struct {
 	URI string `json:"uri"`
 }
 
-func ModuleCallersHandler(ctx context.Context, args cmd.CommandArgs) (interface{}, error) {
+func (h *CmdHandler) ModuleCallersHandler(ctx context.Context, args cmd.CommandArgs) (interface{}, error) {
 	modUri, ok := args.GetString("uri")
 	if !ok || modUri == "" {
 		return nil, fmt.Errorf("%w: expected module uri argument to be set", code.InvalidParams.Err())
@@ -37,12 +36,7 @@ func ModuleCallersHandler(ctx context.Context, args cmd.CommandArgs) (interface{
 		return nil, err
 	}
 
-	mf, err := lsctx.ModuleFinder(ctx)
-	if err != nil {
-		return nil, err
-	}
-
-	modCallers, err := mf.CallersOfModule(modPath)
+	modCallers, err := h.StateStore.Modules.CallersOfModule(modPath)
 	if err != nil {
 		return nil, err
 	}

internal/langserver/handlers/command/module_calls.go

@@ -7,7 +7,6 @@ import (
 	"strings"
 
 	"github.com/creachadair/jrpc2/code"
-	lsctx "github.com/hashicorp/terraform-ls/internal/context"
 	"github.com/hashicorp/terraform-ls/internal/langserver/cmd"
 	"github.com/hashicorp/terraform-ls/internal/terraform/datadir"
 	"github.com/hashicorp/terraform-ls/internal/uri"
@@ -29,7 +28,7 @@ type moduleCall struct {
 	DependentModules []moduleCall       `json:"dependent_modules"`
 }
 
-func ModuleCallsHandler(ctx context.Context, args cmd.CommandArgs) (interface{}, error) {
+func (h *CmdHandler) ModuleCallsHandler(ctx context.Context, args cmd.CommandArgs) (interface{}, error) {
 	response := moduleCallsResponse{
 		FormatVersion: moduleCallsVersion,
 		ModuleCalls:   make([]moduleCall, 0),
@@ -49,12 +48,7 @@ func ModuleCallsHandler(ctx context.Context, args cmd.CommandArgs) (interface{},
 		return response, err
 	}
 
-	mm, err := lsctx.ModuleFinder(ctx)
-	if err != nil {
-		return response, err
-	}
-
-	found, _ := mm.ModuleByPath(modPath)
+	found, _ := h.StateStore.Modules.ModuleByPath(modPath)
 	if found == nil {
 		return response, nil
 	}

internal/langserver/handlers/command/module_providers.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 
 	"github.com/creachadair/jrpc2/code"
-	lsctx "github.com/hashicorp/terraform-ls/internal/context"
 	"github.com/hashicorp/terraform-ls/internal/langserver/cmd"
 	op "github.com/hashicorp/terraform-ls/internal/terraform/module/operation"
 	"github.com/hashicorp/terraform-ls/internal/uri"
@@ -26,7 +25,7 @@ type providerRequirement struct {
 	DocsLink          string `json:"docs_link,omitempty"`
 }
 
-func ModuleProvidersHandler(ctx context.Context, args cmd.CommandArgs) (interface{}, error) {
+func (h *CmdHandler) ModuleProvidersHandler(ctx context.Context, args cmd.CommandArgs) (interface{}, error) {
 	response := moduleProvidersResponse{
 		FormatVersion:        moduleProvidersVersion,
 		ProviderRequirements: make(map[string]providerRequirement),
@@ -47,12 +46,7 @@ func ModuleProvidersHandler(ctx context.Context, args cmd.CommandArgs) (interfac
 		return response, err
 	}
 
-	mm, err := lsctx.ModuleFinder(ctx)
-	if err != nil {
-		return response, err
-	}
-
-	mod, _ := mm.ModuleByPath(modPath)
+	mod, _ := h.StateStore.Modules.ModuleByPath(modPath)
 	if mod == nil {
 		return response, nil
 	}