refactor(extensions): per-queue Factory; drop queue from method signatures

## Summary

### Why?

Behavioral extensions were global singletons frozen at process start, and two
leaked the queue into vendor-agnostic method signatures (mergechecker.Check,
buildrunner.Trigger). Each extension should instead be produced by a Factory
the controller asks for using the queue, identified only by name, so an
implementation can be selected/configured per queue.

### What?

- Reduce entity.QueueConfig to {Name} (the registry of valid queues); all
  behavioral/VCS config moves into the factory implementations.
- Each extension (changeprovider, pusher, scorer, conflict, mergechecker,
  buildrunner) ships a narrow Config{QueueName} and a Factory interface
  (For(cfg) (T, error)); concrete factories are written by integrators in the
  example wiring and tests. Generated mocks updated.
- Drop the queue argument from mergechecker.Check(ctx, change) and
  buildrunner.Trigger(ctx, base, head, metadata); delete mergechecker
  MultiChecker. Status/Cancel stay buildID-keyed.
- Add storage.Factory (default mysql) and thread it into every controller; the
  gateway land controller resolves For(req.Queue) — the one place per-queue
  storage routing is actionable. Orchestrator controllers carry a
  TODO(queue-aware) to derive the queue from the loaded entity for
  logging/metrics/storage.
- Controllers resolve each extension from its Factory using the loaded entity's
  queue; buildsignal fetches the batch before polling Status. Example servers
  wire concrete static factory structs.

## Test Plan

✅ make build, make test (40 pass)
✅ make fmt / lint / check-gazelle / check-tidy / check-mocks

Author: behinddwalls

Makefile

@@ -334,7 +334,7 @@ local-stovepipe-gateway-start: build-stovepipe-gateway-linux ## Start Stovepipe
 
 mocks: ## Generate mock files using mockgen
 	@echo "Generating mocks..."
-	@$(BAZEL) run @rules_go//go -- generate ./submitqueue/extension/storage/... ./submitqueue/extension/buildrunner/... ./submitqueue/extension/changestore/... ./extension/counter/... ./extension/messagequeue/... ./submitqueue/extension/queueconfig/... ./submitqueue/extension/mergechecker/... ./submitqueue/extension/pusher/... ./submitqueue/extension/scorer/... ./submitqueue/extension/conflict/... ./submitqueue/core/consumer/...
+	@$(BAZEL) run @rules_go//go -- generate ./submitqueue/extension/storage/... ./submitqueue/extension/buildrunner/... ./submitqueue/extension/changeprovider/... ./submitqueue/extension/changestore/... ./extension/counter/... ./extension/messagequeue/... ./submitqueue/extension/queueconfig/... ./submitqueue/extension/mergechecker/... ./submitqueue/extension/pusher/... ./submitqueue/extension/scorer/... ./submitqueue/extension/conflict/... ./submitqueue/core/consumer/...
 	@echo "Mocks generated successfully!"
 
 proto: ## Generate protobuf files from .proto definitions

example/submitqueue/gateway/server/BUILD.bazel

@@ -15,6 +15,7 @@ go_library(
         "//extension/messagequeue/mysql",
         "//submitqueue/core/consumer",
         "//submitqueue/extension/queueconfig/yaml",
+        "//submitqueue/extension/storage",
         "//submitqueue/extension/storage/mysql",
         "//submitqueue/gateway/controller",
         "//submitqueue/gateway/protopb",

example/submitqueue/gateway/server/main.go

@@ -32,6 +32,7 @@ import (
 	queueMySQL "github.com/uber/submitqueue/extension/messagequeue/mysql"
 	"github.com/uber/submitqueue/submitqueue/core/consumer"
 	yamlqueueconfig "github.com/uber/submitqueue/submitqueue/extension/queueconfig/yaml"
+	"github.com/uber/submitqueue/submitqueue/extension/storage"
 	mysqlstorage "github.com/uber/submitqueue/submitqueue/extension/storage/mysql"
 	"github.com/uber/submitqueue/submitqueue/gateway/controller"
 	pb "github.com/uber/submitqueue/submitqueue/gateway/protopb"
@@ -199,8 +200,15 @@ func run() error {
 		},
 	))
 
-	// Initialize request log store from shared app database connection
-	requestLogStore := mysqlstorage.NewRequestLogStore(appDB, scope.SubScope("request_log_store"))
+	// Initialize storage from the shared app database connection. The land
+	// controller takes a storage.Factory (static: every queue → this store);
+	// cancel/status use the request log store directly.
+	store, err := mysqlstorage.NewStorage(appDB, scope.SubScope("storage"))
+	if err != nil {
+		return fmt.Errorf("failed to create storage: %w", err)
+	}
+	stores := storage.NewStaticFactory(store)
+	requestLogStore := store.GetRequestLogStore()
 
 	// Load queue configurations from YAML. Path is required so the gateway
 	// can reject requests for unknown queues at the edge.
@@ -215,7 +223,7 @@ func run() error {
 
 	// Create controllers and wrap them for gRPC
 	pingController := controller.NewPingController(logger, scope)
-	landController := controller.NewLandController(logger.Sugar(), scope, cnt, requestLogStore, queueConfigs, registry)
+	landController := controller.NewLandController(logger.Sugar(), scope, cnt, stores, queueConfigs, registry)
 	cancelController := controller.NewCancelController(logger.Sugar(), scope, requestLogStore, registry)
 	statusController := controller.NewStatusController(logger.Sugar(), scope, requestLogStore)
 	gatewayServer := &GatewayServer{

example/submitqueue/gateway/server/queues.yaml

@@ -1,31 +1,9 @@
 # Example queue configurations consumed by the gateway YAML store.
-# The gateway loads this file at startup; QUEUE_CONFIG_PATH must point
-# at it. Each entry maps a queue name to the VCS repository + target
-# branch and selects the extension implementations used downstream.
+# The gateway loads this file at startup; QUEUE_CONFIG_PATH must point at it.
+# QueueConfig is just the registry of valid queue names — all behavioral and
+# VCS configuration lives in the extension factory implementations wired in the
+# server, not here.
 queues:
   - name: test-queue
-    vcs_type: git
-    vcs_address: git@github.com:uber/submitqueue.git
-    target: main
-    build_runner: buildkite.com/uber/submitqueue-ci
-    change_provider: github
-    merge_checker: github
-    land_provider: github
-
   - name: e2e-test-queue
-    vcs_type: git
-    vcs_address: git@github.com:uber/submitqueue.git
-    target: main
-    build_runner: buildkite.com/uber/submitqueue-ci
-    change_provider: github
-    merge_checker: github
-    land_provider: github
-
   - name: e2e-cancel-queue
-    vcs_type: git
-    vcs_address: git@github.com:uber/submitqueue.git
-    target: main
-    build_runner: buildkite.com/uber/submitqueue-ci
-    change_provider: github
-    merge_checker: github
-    land_provider: github

example/submitqueue/orchestrator/server/BUILD.bazel

@@ -26,11 +26,13 @@ go_library(
         "//submitqueue/extension/changeprovider/github",
         "//submitqueue/extension/changestore",
         "//submitqueue/extension/changestore/mysql",
+        "//submitqueue/extension/conflict",
         "//submitqueue/extension/conflict/all",
         "//submitqueue/extension/mergechecker",
         "//submitqueue/extension/mergechecker/github",
         "//submitqueue/extension/pusher",
         "//submitqueue/extension/pusher/git",
+        "//submitqueue/extension/scorer",
         "//submitqueue/extension/scorer/heuristic",
         "//submitqueue/extension/storage",
         "//submitqueue/extension/storage/mysql",

example/submitqueue/orchestrator/server/main.go

@@ -45,11 +45,13 @@ import (
 	githubprovider "github.com/uber/submitqueue/submitqueue/extension/changeprovider/github"
 	"github.com/uber/submitqueue/submitqueue/extension/changestore"
 	mysqlchangestore "github.com/uber/submitqueue/submitqueue/extension/changestore/mysql"
+	"github.com/uber/submitqueue/submitqueue/extension/conflict"
 	"github.com/uber/submitqueue/submitqueue/extension/conflict/all"
 	"github.com/uber/submitqueue/submitqueue/extension/mergechecker"
 	githubchecker "github.com/uber/submitqueue/submitqueue/extension/mergechecker/github"
 	"github.com/uber/submitqueue/submitqueue/extension/pusher"
 	gitpusher "github.com/uber/submitqueue/submitqueue/extension/pusher/git"
+	"github.com/uber/submitqueue/submitqueue/extension/scorer"
 	"github.com/uber/submitqueue/submitqueue/extension/scorer/heuristic"
 	"github.com/uber/submitqueue/submitqueue/extension/storage"
 	mysqlstorage "github.com/uber/submitqueue/submitqueue/extension/storage/mysql"
@@ -425,11 +427,48 @@ func newTopicRegistry(q extqueue.Queue, subscriberName string) (consumer.TopicRe
 //                                        │        │                       │
 //                                        └────────┴───────────────────────┘
 
+// Static per-extension factories for the example server: every queue resolves
+// to the single configured implementation. A real deployment would vary the
+// returned implementation by cfg.QueueName (and inject per-queue config).
+type changeProviderFactory struct{ impl changeprovider.ChangeProvider }
+
+func (f changeProviderFactory) For(changeprovider.Config) (changeprovider.ChangeProvider, error) {
+	return f.impl, nil
+}
+
+type mergeCheckerFactory struct{ impl mergechecker.MergeChecker }
+
+func (f mergeCheckerFactory) For(mergechecker.Config) (mergechecker.MergeChecker, error) {
+	return f.impl, nil
+}
+
+type pusherFactory struct{ impl pusher.Pusher }
+
+func (f pusherFactory) For(pusher.Config) (pusher.Pusher, error) { return f.impl, nil }
+
+type buildRunnerFactory struct{ impl buildrunner.BuildRunner }
+
+func (f buildRunnerFactory) For(buildrunner.Config) (buildrunner.BuildRunner, error) {
+	return f.impl, nil
+}
+
+type scorerFactory struct{ impl scorer.Scorer }
+
+func (f scorerFactory) For(scorer.Config) (scorer.Scorer, error) { return f.impl, nil }
+
+type conflictFactory struct{ impl conflict.Analyzer }
+
+func (f conflictFactory) For(conflict.Config) (conflict.Analyzer, error) { return f.impl, nil }
+
 func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope tally.Scope, registry consumer.TopicRegistry, mc mergechecker.MergeChecker, cp changeprovider.ChangeProvider, psh pusher.Pusher, br buildrunner.BuildRunner, cnt counter.Counter, store storage.Storage, changeStore changestore.ChangeStore) error {
+	// Static storage factory: every queue resolves to the one configured store.
+	// The factory is the injection point for future per-queue backends.
+	stores := storage.NewStaticFactory(store)
+
 	requestController := start.NewController(
 		logger,
 		scope,
-		store,
+		stores,
 		changeStore,
 		registry,
 		consumer.TopicKeyStart,
@@ -442,7 +481,7 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	cancelController := cancel.NewController(
 		logger,
 		scope,
-		store,
+		stores,
 		registry,
 		consumer.TopicKeyCancel,
 		"orchestrator-cancel",
@@ -454,11 +493,11 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	validateController := validate.NewController(
 		logger,
 		scope,
-		store,
+		stores,
 		changeStore,
 		registry,
-		mc,
-		cp,
+		mergeCheckerFactory{impl: mc},
+		changeProviderFactory{impl: cp},
 		consumer.TopicKeyValidate,
 		"orchestrator-validate",
 	)
@@ -471,10 +510,10 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 		scope,
 		registry,
 		cnt,
-		store,
+		stores,
 		// TODO: replace with a real conflict analyzer (e.g. one backed by
 		// Tango target analysis). The "all" stub serializes the queue.
-		all.New(),
+		conflictFactory{impl: all.New()},
 		consumer.TopicKeyBatch,
 		"orchestrator-batch",
 	)
@@ -485,9 +524,9 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	scoreController := score.NewController(
 		logger,
 		scope,
-		store,
+		stores,
 		// TODO: replace with a real scorer
-		heuristic.New(
+		scorerFactory{impl: heuristic.New(
 			[]heuristic.Bucket{
 				{Min: 0, Max: 1, Score: 0.95},
 				{Min: 2, Max: 5, Score: 0.80},
@@ -498,7 +537,7 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 				return len(change.URIs), nil
 			},
 			scope.SubScope("scorer"),
-		),
+		)},
 		registry,
 		consumer.TopicKeyScore,
 		"orchestrator-score",
@@ -510,7 +549,7 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	speculateController := speculate.NewController(
 		logger,
 		scope,
-		store,
+		stores,
 		registry,
 		consumer.TopicKeySpeculate,
 		"orchestrator-speculate",
@@ -522,8 +561,8 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	buildController := build.NewController(
 		logger,
 		scope,
-		store,
-		br,
+		stores,
+		buildRunnerFactory{impl: br},
 		registry,
 		consumer.TopicKeyBuild,
 		"orchestrator-build",
@@ -535,8 +574,8 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	buildsignalController := buildsignal.NewController(
 		logger,
 		scope,
-		store,
-		br,
+		stores,
+		buildRunnerFactory{impl: br},
 		registry,
 		consumer.TopicKeyBuildSignal,
 		"orchestrator-buildsignal",
@@ -548,9 +587,9 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	mergeController := merge.NewController(
 		logger,
 		scope,
-		store,
+		stores,
 		registry,
-		psh,
+		pusherFactory{impl: psh},
 		consumer.TopicKeyMerge,
 		"orchestrator-merge",
 	)
@@ -561,7 +600,7 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	concludeController := conclude.NewController(
 		logger,
 		scope,
-		store,
+		stores,
 		registry,
 		consumer.TopicKeyConclude,
 		"orchestrator-conclude",
@@ -573,7 +612,7 @@ func registerControllers(c consumer.Consumer, logger *zap.SugaredLogger, scope t
 	logController := logctrl.NewController(
 		logger,
 		scope,
-		store,
+		stores,
 		consumer.TopicKeyLog,
 		"orchestrator-log",
 	)
@@ -619,14 +658,10 @@ func newMergeChecker(logger *zap.Logger, scope tally.Scope) (mergechecker.MergeC
 
 	client.Timeout = parseTimeout(os.Getenv("GITHUB_TIMEOUT"), 30*time.Second)
 
-	github := githubchecker.NewMergeChecker(githubchecker.Params{
+	return githubchecker.NewMergeChecker(githubchecker.Params{
 		HTTPClient:   client,
 		Logger:       logger.Sugar(),
 		MetricsScope: scope.SubScope("mergechecker"),
-	})
-
-	return mergechecker.NewMultiChecker(map[string]mergechecker.MergeChecker{
-		"github": github,
 	}), nil
 }
 

submitqueue/entity/queue_config.go

@@ -14,52 +14,13 @@
 
 package entity
 
-// QueueConfig holds the configuration for a single submit queue.
-// Each queue maps a VCS repository + target to a processing pipeline.
-// A repository can have multiple queues, but each queue has exactly one target.
-// Immutable after creation.
+// QueueConfig identifies a single submit queue. It is the registry of valid
+// queue names; the gateway validates that a land request targets a known queue.
+// All behavioral and VCS configuration lives in the extension factory
+// implementations, which are constructed per integrator deployment — the system
+// hands a factory only the queue name. Immutable after creation.
 type QueueConfig struct {
 	// Name uniquely identifies this queue within the system.
 	// Referenced by Request.Queue.
 	Name string `json:"name" yaml:"name"`
-
-	// VCSType identifies the version control system (e.g., "git", "svn", "perforce").
-	// A queue operates on exactly one VCS.
-	VCSType string `json:"vcs_type" yaml:"vcs_type"`
-
-	// VCSAddress identifies the repository in the version control system.
-	// The format is VCS-specific:
-	//   - Git: remote URL (e.g., "git@github.com:uber/submitqueue.git")
-	//   - Perforce: depot path (e.g., "//depot/project")
-	//   - SVN: repository URL (e.g., "https://svn.example.com/repos/project")
-	VCSAddress string `json:"vcs_address" yaml:"vcs_address"`
-
-	// Target is the landing target where changes are merged.
-	// The format is VCS-specific:
-	//   - Git: branch ref (e.g., "main", "release/v2")
-	//   - Perforce: stream or depot path (e.g., "//depot/main/...")
-	//   - SVN: repository path (e.g., "trunk/")
-	Target string `json:"target" yaml:"target"`
-
-	// BuildRunner identifies the CI pipeline or job that runs builds for this queue.
-	// Opaque to the system; meaningful only to the build runner extension implementation.
-	// Examples:
-	//   - Buildkite: "buildkite.com/uber/submitqueue-ci"
-	//   - Jenkins: "jenkins.example.com/job/submitqueue-verify"
-	BuildRunner string `json:"build_runner" yaml:"build_runner"`
-
-	// ChangeProvider identifies the change provider implementation for this queue.
-	// Opaque to the system; meaningful only to the change provider extension implementation.
-	// Examples: "github", "gitlab", "phabricator"
-	ChangeProvider string `json:"change_provider" yaml:"change_provider"`
-
-	// MergeChecker identifies the merge checker implementation for this queue.
-	// Opaque to the system; meaningful only to the merge checker extension implementation.
-	// Examples: "github", "gitlab"
-	MergeChecker string `json:"merge_checker" yaml:"merge_checker"`
-
-	// LandProvider identifies the land provider implementation for this queue.
-	// Opaque to the system; meaningful only to the land provider extension implementation.
-	// Examples: "github", "gitlab"
-	LandProvider string `json:"land_provider" yaml:"land_provider"`
 }

submitqueue/extension/buildrunner/build_runner.go

@@ -55,11 +55,10 @@ type BuildRunner interface {
 	// asynchronously. Callers learn the build's progress via Status, not
 	// via Trigger.
 	//
-	// queueName selects the runner-specific job configuration.
-	// Returns an error if the request is invalid.
+	// The runner is already bound to its queue's job configuration by the
+	// Factory that built it. Returns an error if the request is invalid.
 	Trigger(
 		ctx context.Context,
-		queueName string,
 		base []entity.Change,
 		head []entity.Change,
 		metadata entity.BuildMetadata,
@@ -80,3 +79,18 @@ type BuildRunner interface {
 	// on already-terminal builds. Returns an error if the build does not exist.
 	Cancel(ctx context.Context, buildID entity.BuildID) error
 }
+
+// Config carries the per-queue identity handed to a Factory. The system knows
+// only the queue name; everything an implementation needs (endpoint, pipeline,
+// credentials) is injected at construction by the integrator.
+type Config struct {
+	// QueueName identifies the queue this BuildRunner serves.
+	QueueName string
+}
+
+// Factory builds the BuildRunner for a queue. Implementations are provided by
+// integrators (and tests) and inject whatever they need at construction.
+type Factory interface {
+	// For returns the BuildRunner for the given queue.
+	For(cfg Config) (BuildRunner, error)
+}

submitqueue/extension/buildrunner/mock/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//submitqueue/entity",
+        "//submitqueue/extension/buildrunner",
         "@org_uber_go_mock//gomock",
     ],
 )