refactor(http): modify query handler to use a language service (#17074)

The language service abstracts away the parse source which breaks the
dependency without moving any of the code.

cmd/influxd/launcher/launcher.go

@@ -38,6 +38,7 @@ import (
 	infprom "github.com/influxdata/influxdb/prometheus"
 	"github.com/influxdata/influxdb/query"
 	"github.com/influxdata/influxdb/query/control"
+	"github.com/influxdata/influxdb/query/fluxlang"
 	"github.com/influxdata/influxdb/query/stdlib/influxdata/influxdb"
 	"github.com/influxdata/influxdb/snowflake"
 	"github.com/influxdata/influxdb/source"
@@ -795,6 +796,7 @@ func (m *Launcher) run(ctx context.Context) (err error) {
 		OnboardingService:               onboardingSvc,
 		InfluxQLService:                 nil, // No InfluxQL support
 		FluxService:                     storageQueryService,
+		FluxLanguageService:             fluxlang.DefaultService,
 		TaskService:                     taskSvc,
 		TelegrafService:                 telegrafSvc,
 		NotificationRuleStore:           notificationRuleSvc,

http/api_handler.go

@@ -72,6 +72,7 @@ type APIBackend struct {
 	OnboardingService               influxdb.OnboardingService
 	InfluxQLService                 query.ProxyQueryService
 	FluxService                     query.ProxyQueryService
+	FluxLanguageService             influxdb.FluxLanguageService
 	TaskService                     influxdb.TaskService
 	CheckService                    influxdb.CheckService
 	TelegrafService                 influxdb.TelegrafConfigStore

http/query.go

@@ -18,7 +18,6 @@ import (
 	"github.com/influxdata/flux/ast"
 	"github.com/influxdata/flux/csv"
 	"github.com/influxdata/flux/lang"
-	"github.com/influxdata/flux/parser"
 	"github.com/influxdata/flux/repl"
 	"github.com/influxdata/influxdb"
 	"github.com/influxdata/influxdb/jsonweb"
@@ -145,10 +144,10 @@ type queryParseError struct {
 
 // Analyze attempts to parse the query request and returns any errors
 // encountered in a structured way.
-func (r QueryRequest) Analyze() (*QueryAnalysis, error) {
+func (r QueryRequest) Analyze(l influxdb.FluxLanguageService) (*QueryAnalysis, error) {
 	switch r.Type {
 	case "flux":
-		return r.analyzeFluxQuery()
+		return r.analyzeFluxQuery(l)
 	case "influxql":
 		return r.analyzeInfluxQLQuery()
 	}
@@ -156,9 +155,12 @@ func (r QueryRequest) Analyze() (*QueryAnalysis, error) {
 	return nil, fmt.Errorf("unknown query request type %s", r.Type)
 }
 
-func (r QueryRequest) analyzeFluxQuery() (*QueryAnalysis, error) {
+func (r QueryRequest) analyzeFluxQuery(l influxdb.FluxLanguageService) (*QueryAnalysis, error) {
 	a := &QueryAnalysis{}
-	pkg := parser.ParseSource(r.Query)
+	pkg, err := l.Parse(r.Query)
+	if pkg == nil {
+		return nil, err
+	}
 	errCount := ast.Check(pkg)
 	if errCount == 0 {
 		a.Errors = []queryParseError{}

http/query_handler.go

@@ -17,7 +17,6 @@ import (
 	"github.com/influxdata/flux/complete"
 	"github.com/influxdata/flux/csv"
 	"github.com/influxdata/flux/iocounter"
-	"github.com/influxdata/flux/parser"
 	"github.com/influxdata/httprouter"
 	"github.com/influxdata/influxdb"
 	pcontext "github.com/influxdata/influxdb/context"
@@ -46,6 +45,7 @@ type FluxBackend struct {
 
 	OrganizationService influxdb.OrganizationService
 	ProxyQueryService   query.ProxyQueryService
+	FluxLanguageService influxdb.FluxLanguageService
 }
 
 // NewFluxBackend returns a new instance of FluxBackend.
@@ -57,6 +57,7 @@ func NewFluxBackend(log *zap.Logger, b *APIBackend) *FluxBackend {
 
 		ProxyQueryService:   b.FluxService,
 		OrganizationService: b.OrganizationService,
+		FluxLanguageService: b.FluxLanguageService,
 	}
 }
 
@@ -74,6 +75,7 @@ type FluxHandler struct {
 	Now                 func() time.Time
 	OrganizationService influxdb.OrganizationService
 	ProxyQueryService   query.ProxyQueryService
+	LanguageService     influxdb.FluxLanguageService
 
 	EventRecorder metric.EventRecorder
 }
@@ -94,6 +96,7 @@ func NewFluxHandler(log *zap.Logger, b *FluxBackend) *FluxHandler {
 		ProxyQueryService:   b.ProxyQueryService,
 		OrganizationService: b.OrganizationService,
 		EventRecorder:       b.QueryEventRecorder,
+		LanguageService:     b.FluxLanguageService,
 	}
 
 	// query reponses can optionally be gzip encoded
@@ -216,9 +219,8 @@ func (h *FluxHandler) postFluxAST(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	pkg := parser.ParseSource(request.Query)
-	if ast.Check(pkg) > 0 {
-		err := ast.GetError(pkg)
+	pkg, err := h.LanguageService.Parse(request.Query)
+	if err != nil {
 		h.HandleHTTPError(ctx, &influxdb.Error{
 			Code: influxdb.EInvalid,
 			Msg:  "invalid AST",
@@ -254,7 +256,7 @@ func (h *FluxHandler) postQueryAnalyze(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	a, err := req.Analyze()
+	a, err := req.Analyze(h.LanguageService)
 	if err != nil {
 		h.HandleHTTPError(ctx, err, w)
 		return

http/query_handler_test.go

@@ -28,6 +28,7 @@ import (
 	kithttp "github.com/influxdata/influxdb/kit/transport/http"
 	influxmock "github.com/influxdata/influxdb/mock"
 	"github.com/influxdata/influxdb/query"
+	"github.com/influxdata/influxdb/query/fluxlang"
 	"github.com/influxdata/influxdb/query/mock"
 	"go.uber.org/zap/zaptest"
 )
@@ -260,6 +261,7 @@ func TestFluxHandler_postFluxAST(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			h := &FluxHandler{
 				HTTPErrorHandler: kithttp.ErrorHandler(0),
+				LanguageService:  fluxlang.DefaultService,
 			}
 			h.postFluxAST(tt.w, tt.r)
 			if got := tt.w.Body.String(); got != tt.want {
@@ -338,6 +340,7 @@ func TestFluxHandler_PostQuery_Errors(t *testing.T) {
 				}
 			},
 		},
+		FluxLanguageService: fluxlang.DefaultService,
 	}
 	h := NewFluxHandler(zaptest.NewLogger(t), b)
 
@@ -497,6 +500,7 @@ func TestFluxService_Query_gzip(t *testing.T) {
 		QueryEventRecorder:  noopEventRecorder{},
 		OrganizationService: orgService,
 		ProxyQueryService:   queryService,
+		FluxLanguageService: fluxlang.DefaultService,
 	}
 
 	fluxHandler := NewFluxHandler(zaptest.NewLogger(t), fluxBackend)
@@ -633,6 +637,7 @@ func benchmarkQuery(b *testing.B, disableCompression bool) {
 		QueryEventRecorder:  noopEventRecorder{},
 		OrganizationService: orgService,
 		ProxyQueryService:   queryService,
+		FluxLanguageService: fluxlang.DefaultService,
 	}
 
 	fluxHandler := NewFluxHandler(zaptest.NewLogger(b), fluxBackend)

query.go

@@ -1,5 +1,7 @@
 package influxdb
 
+import "github.com/influxdata/flux/ast"
+
 // TODO(desa): These files are possibly a temporary. This is needed
 // as a part of the source work that is being done.
 // See https://github.com/influxdata/platform/issues/594 for more info.
@@ -9,3 +11,12 @@ type SourceQuery struct {
 	Query string `json:"query"`
 	Type  string `json:"type"`
 }
+
+// FluxLanguageService is a service for interacting with flux code.
+type FluxLanguageService interface {
+	// Parse will take flux source code and produce a package.
+	// If there are errors when parsing, the first error is returned.
+	// An ast.Package may be returned when a parsing error occurs,
+	// but it may be null if parsing didn't even occur.
+	Parse(source string) (*ast.Package, error)
+}

query/fluxlang/service.go

@@ -0,0 +1,21 @@
+// Package language exposes the flux parser as an interface.
+package fluxlang
+
+import (
+	"github.com/influxdata/flux/ast"
+	"github.com/influxdata/flux/parser"
+	"github.com/influxdata/influxdb"
+)
+
+// DefaultService is the default language service.
+var DefaultService influxdb.FluxLanguageService = defaultService{}
+
+type defaultService struct{}
+
+func (d defaultService) Parse(source string) (pkg *ast.Package, err error) {
+	pkg = parser.ParseSource(source)
+	if ast.Check(pkg) > 0 {
+		err = ast.GetError(pkg)
+	}
+	return pkg, err
+}