fix(router): do not reuse planners in the plan generator

router-tests/go.mod

@@ -27,7 +27,7 @@ require (
 	github.com/wundergraph/cosmo/demo/pkg/subgraphs/projects v0.0.0-20250715110703-10f2e5f9c79e
 	github.com/wundergraph/cosmo/router v0.0.0-20260213130455-6e3277e7b850
 	github.com/wundergraph/cosmo/router-plugin v0.0.0-20250808194725-de123ba1c65e
-	github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.252
+	github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.253
 	go.opentelemetry.io/otel v1.36.0
 	go.opentelemetry.io/otel/sdk v1.36.0
 	go.opentelemetry.io/otel/sdk/metric v1.36.0

router-tests/go.sum

@@ -356,8 +356,8 @@ github.com/wundergraph/astjson v1.0.0 h1:rETLJuQkMWWW03HCF6WBttEBOu8gi5vznj5KEUP
 github.com/wundergraph/astjson v1.0.0/go.mod h1:h12D/dxxnedtLzsKyBLK7/Oe4TAoGpRVC9nDpDrZSWw=
 github.com/wundergraph/go-arena v1.1.0 h1:9+wSRkJAkA2vbYHp6s8tEGhPViRGQNGXqPHT0QzhdIc=
 github.com/wundergraph/go-arena v1.1.0/go.mod h1:ROOysEHWJjLQ8FSfNxZCziagb7Qw2nXY3/vgKRh7eWw=
-github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.252 h1:qhm6obHtRwgZm84Gu3G63ywGz2ys2xLBwC0gloDKZuo=
-github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.252/go.mod h1:MFbY0QI8ncF60DHs7yyyiyyhWyld0WE1JokiyTVY8j4=
+github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.253 h1:QW7wGThQdplffQHkePTmJ/Lh32ZXB8EEOq3zC/v48yg=
+github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.253/go.mod h1:MFbY0QI8ncF60DHs7yyyiyyhWyld0WE1JokiyTVY8j4=
 github.com/xrash/smetrics v0.0.0-20250705151800-55b8f293f342 h1:FnBeRrxr7OU4VvAzt5X7s6266i6cSVkkFPS0TuXWbIg=
 github.com/xrash/smetrics v0.0.0-20250705151800-55b8f293f342/go.mod h1:Ohn+xnUBiLI6FVj/9LpzZWtj1/D6lUovWYBkxHVV3aM=
 github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=

router/go.mod

@@ -31,7 +31,7 @@ require (
 	github.com/tidwall/gjson v1.18.0
 	github.com/tidwall/sjson v1.2.5
 	github.com/twmb/franz-go v1.16.1
-	github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.252
+	github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.253
 	// Do not upgrade, it renames attributes we rely on
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.58.0
 	go.opentelemetry.io/contrib/propagators/b3 v1.23.0

router/go.sum

@@ -326,8 +326,8 @@ github.com/wundergraph/astjson v1.0.0 h1:rETLJuQkMWWW03HCF6WBttEBOu8gi5vznj5KEUP
 github.com/wundergraph/astjson v1.0.0/go.mod h1:h12D/dxxnedtLzsKyBLK7/Oe4TAoGpRVC9nDpDrZSWw=
 github.com/wundergraph/go-arena v1.1.0 h1:9+wSRkJAkA2vbYHp6s8tEGhPViRGQNGXqPHT0QzhdIc=
 github.com/wundergraph/go-arena v1.1.0/go.mod h1:ROOysEHWJjLQ8FSfNxZCziagb7Qw2nXY3/vgKRh7eWw=
-github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.252 h1:qhm6obHtRwgZm84Gu3G63ywGz2ys2xLBwC0gloDKZuo=
-github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.252/go.mod h1:MFbY0QI8ncF60DHs7yyyiyyhWyld0WE1JokiyTVY8j4=
+github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.253 h1:QW7wGThQdplffQHkePTmJ/Lh32ZXB8EEOq3zC/v48yg=
+github.com/wundergraph/graphql-go-tools/v2 v2.0.0-rc.253/go.mod h1:MFbY0QI8ncF60DHs7yyyiyyhWyld0WE1JokiyTVY8j4=
 github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=
 github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT040gmv5BQTMR2HP4=
 github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=

router/pkg/plan_generator/plan_generator.go

@@ -49,6 +49,9 @@ type QueryPlanResult struct {
 	Timings  core.OperationTimes `json:"timings,omitempty"`
 }
 
+// PlanGenerator reads GraphQL operation files from cfg.SourceDir,
+// generates query plans for each using the execution config,
+// and writes results to cfg.OutDir as individual files and/or a consolidated report.
 func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 	if cfg.Concurrency == 0 {
 		cfg.Concurrency = runtime.GOMAXPROCS(0)
@@ -60,35 +63,35 @@ func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 
 	queriesPath, err := filepath.Abs(cfg.SourceDir)
 	if err != nil {
-		return fmt.Errorf("failed to get absolute path for queries: %v", err)
+		return fmt.Errorf("failed to get absolute path for queries: %w", err)
 	}
 
 	outPath, err := filepath.Abs(cfg.OutDir)
 	if err != nil {
-		return fmt.Errorf("failed to get absolute path for output: %v", err)
+		return fmt.Errorf("failed to get absolute path for output: %w", err)
 	}
 	if err := os.MkdirAll(outPath, 0755); err != nil {
-		return fmt.Errorf("failed to create output directory: %v", err)
+		return fmt.Errorf("failed to create output directory: %w", err)
 	}
 
 	executionConfigPath, err := filepath.Abs(cfg.ExecutionConfig)
 	if err != nil {
-		return fmt.Errorf("failed to get absolute path for execution config: %v", err)
+		return fmt.Errorf("failed to get absolute path for execution config: %w", err)
 	}
 
 	var filter []string
 	if cfg.Filter != "" {
 		filterContent, err := os.ReadFile(cfg.Filter)
 		if err != nil {
-			return fmt.Errorf("failed to read filter file: %v", err)
+			return fmt.Errorf("failed to read filter file: %w", err)
 		}
 
 		filter = strings.Split(string(filterContent), "\n")
 	}
 
 	queries, err := os.ReadDir(queriesPath)
 	if err != nil {
-		return fmt.Errorf("failed to read queries directory: %v", err)
+		return fmt.Errorf("failed to read queries directory: %w", err)
 	}
 
 	queriesQueue := make(chan os.DirEntry, len(queries))
@@ -102,7 +105,7 @@ func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 
 	duration, parseErr := time.ParseDuration(cfg.Timeout)
 	if parseErr != nil {
-		return fmt.Errorf("failed to parse timeout: %v", parseErr)
+		return fmt.Errorf("failed to parse timeout: %w", parseErr)
 	}
 	ctx, cancel := context.WithTimeout(ctx, duration)
 	defer cancel()
@@ -111,7 +114,7 @@ func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 
 	pg, err := core.NewPlanGenerator(executionConfigPath, cfg.Logger, cfg.MaxDataSourceCollectorsConcurrency)
 	if err != nil {
-		return fmt.Errorf("failed to create plan generator: %v", err)
+		return fmt.Errorf("failed to create plan generator: %w", err)
 	}
 
 	var planError atomic.Bool
@@ -120,13 +123,6 @@ func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 	for i := 0; i < cfg.Concurrency; i++ {
 		go func(i int) {
 			defer wg.Done()
-			planner, err := pg.GetPlanner()
-			if err != nil {
-				// if we fail to get the planner, we need to cancel the context to stop the other goroutines
-				// and return here to stop the current goroutine
-				cancelError(fmt.Errorf("failed to get planner: %v", err))
-				return
-			}
 			for {
 				select {
 				case <-ctxError.Done():
@@ -146,6 +142,15 @@ func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 
 					queryFilePath := filepath.Join(queriesPath, queryFile.Name())
 
+					// Planners should not be reused.
+					planner, err := pg.GetPlanner()
+					if err != nil {
+						// If we fail to get the planner, we have to cancel the context
+						// to stop this and the other goroutines via ctxError.
+						cancelError(fmt.Errorf("failed to get a planner: %w", err))
+						return
+					}
+
 					outContent, opTimes, err := planner.PlanOperation(queryFilePath, cfg.OutputFormat)
 					res := QueryPlanResult{
 						FileName: queryFile.Name(),
@@ -170,7 +175,7 @@ func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 						outFileName := filepath.Join(outPath, queryFile.Name())
 						err = os.WriteFile(outFileName, []byte(outContent), 0644)
 						if err != nil {
-							cancelError(fmt.Errorf("failed to write file: %v", err))
+							cancelError(fmt.Errorf("failed to write file: %w", err))
 						}
 					}
 					resultsMux.Lock()
@@ -187,7 +192,7 @@ func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 		reportFile, err := os.Create(reportFilePath)
 		if err != nil {
 			cancel()
-			return fmt.Errorf("failed to create results file: %v", err)
+			return fmt.Errorf("failed to create results file: %w", err)
 		}
 		defer func() {
 			_ = reportFile.Close()
@@ -203,11 +208,11 @@ func PlanGenerator(ctx context.Context, cfg QueryPlanConfig) error {
 		}
 		data, jsonErr := json.Marshal(resultData)
 		if jsonErr != nil {
-			return fmt.Errorf("failed to marshal result: %v", jsonErr)
+			return fmt.Errorf("failed to marshal result: %w", jsonErr)
 		}
 		_, writeErr := fmt.Fprintf(reportFile, "%s\n", data)
 		if writeErr != nil {
-			return fmt.Errorf("failed to write result: %v", writeErr)
+			return fmt.Errorf("failed to write result: %w", writeErr)
 		}
 	}
 

router/pkg/plan_generator/plan_generator_test.go

@@ -407,3 +407,21 @@ func TestPlanGenerator(t *testing.T) {
 	})
 
 }
+
+func BenchmarkPlanGenerator(b *testing.B) {
+	tempDir := b.TempDir()
+	cfg := QueryPlanConfig{
+		SourceDir:       path.Join(getTestDataDir(), "queries", "bench"),
+		OutDir:          tempDir,
+		ExecutionConfig: path.Join(getTestDataDir(), "execution_config", "base.json"),
+		Timeout:         "30s",
+		Concurrency:     1,
+	}
+	b.ReportAllocs()
+	for b.Loop() {
+		err := PlanGenerator(context.Background(), cfg)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}

router/pkg/plan_generator/testdata/queries/bench/full.graphql

@@ -0,0 +1,125 @@
+query Full {
+  employees {
+    # resolved through employees subgraph
+    id
+    # overridden by the products subgraph
+    notes
+    details {
+      # resolved through either employees or family subgraph
+      forename
+      surname
+      # resolved through employees subgraph
+      location {
+        language
+      }
+      # resolved through family subgraph
+      hasChildren
+      # maritalStatus can return null
+      maritalStatus
+      nationality
+      # pets can return null
+      pets {
+        class
+        gender
+        name
+        ... on Cat {
+          type
+        }
+        ... on Dog {
+          breed
+        }
+        ... on Alligator {
+          dangerous
+        }
+      }
+    }
+    # resolved through employees subgraph
+    role {
+      departments
+      title
+      ... on Engineer {
+        engineerType
+      }
+      ... on Operator {
+        operatorType
+      }
+    }
+    # resolved through hobbies subgraph
+    hobbies {
+      ... on Exercise {
+        category
+      }
+      ... on Flying {
+        planeModels
+        yearsOfExperience
+      }
+      ... on Gaming {
+        genres
+        name
+        yearsOfExperience
+      }
+      ... on Other {
+        name
+      }
+      ... on Programming {
+        languages
+      }
+      ... on Travelling {
+        countriesLived {
+          language
+          key {
+            name
+          }
+        }
+      }
+    }
+    # resolved through products subgraph
+    products
+  }
+  # can return null
+  employee(id: 1) {
+    # resolved through employees subgraph
+    id
+    details {
+      forename
+      location {
+        language
+      }
+    }
+  }
+  teammates(team: OPERATIONS) {
+    # resolved through employees subgraph
+    id
+    ...EmployeeNameFragment
+    # resolved through products subgraph
+    products
+  }
+  productTypes {
+    ... on Documentation {
+      url(product: SDK)
+      urls(products: [COSMO, MARKETING])
+    }
+    ... on Consultancy {
+      lead {
+        ...EmployeeNameFragment
+      }
+      name
+    }
+  }
+  a: findEmployees(criteria: {
+    hasPets: true, nationality: UKRAINIAN, nested: { maritalStatus: ENGAGED }
+  }) {
+    ...EmployeeNameFragment
+  }
+  b: findEmployees(criteria: {
+    hasPets: true, nationality: GERMAN, nested: { maritalStatus: MARRIED, hasChildren: true }
+  }) {
+    ...EmployeeNameFragment
+  }
+}
+
+fragment EmployeeNameFragment on Employee {
+  details {
+    forename
+  }
+}