1 files changed, 327 insertions, 0 deletions
diff --git a/pkg/pool/static_pool.go b/pkg/pool/static_pool.go
new file mode 100755
index 00000000..44adf9c0
--- /dev/null
+++ b/pkg/pool/static_pool.go
@@ -0,0 +1,327 @@
+package pool
+
+import (
+	"context"
+	"os/exec"
+	"time"
+
+	"github.com/spiral/errors"
+	"github.com/spiral/roadrunner/v2/internal"
+	"github.com/spiral/roadrunner/v2/pkg/events"
+	"github.com/spiral/roadrunner/v2/pkg/payload"
+	"github.com/spiral/roadrunner/v2/pkg/transport"
+	"github.com/spiral/roadrunner/v2/pkg/worker"
+	workerWatcher "github.com/spiral/roadrunner/v2/pkg/worker_watcher"
+)
+
+// StopRequest can be sent by worker to indicate that restart is required.
+const StopRequest = "{\"stop\":true}"
+
+// ErrorEncoder encode error or make a decision based on the error type
+type ErrorEncoder func(err error, w worker.SyncWorker) (payload.Payload, error)
+
+type Options func(p *StaticPool)
+
+type Command func() *exec.Cmd
+
+// StaticPool controls worker creation, destruction and task routing. Pool uses fixed amount of stack.
+type StaticPool struct {
+	cfg Config
+
+	// worker command creator
+	cmd Command
+
+	// creates and connects to stack
+	factory transport.Factory
+
+	// distributes the events
+	events events.Handler
+
+	// saved list of event listeners
+	listeners []events.Listener
+
+	// manages worker states and TTLs
+	ww workerWatcher.Watcher
+
+	// allocate new worker
+	allocator worker.Allocator
+
+	// errEncoder is the default Exec error encoder
+	errEncoder ErrorEncoder
+}
+
+// Initialize creates new worker pool and task multiplexer. StaticPool will initiate with one worker.
+func Initialize(ctx context.Context, cmd Command, factory transport.Factory, cfg Config, options ...Options) (Pool, error) {
+	const op = errors.Op("static_pool_initialize")
+	if factory == nil {
+		return nil, errors.E(op, errors.Str("no factory initialized"))
+	}
+	cfg.InitDefaults()
+
+	if cfg.Debug {
+		cfg.NumWorkers = 0
+		cfg.MaxJobs = 1
+	}
+
+	p := &StaticPool{
+		cfg:     cfg,
+		cmd:     cmd,
+		factory: factory,
+		events:  events.NewEventsHandler(),
+	}
+
+	// add pool options
+	for i := 0; i < len(options); i++ {
+		options[i](p)
+	}
+
+	p.allocator = p.newPoolAllocator(ctx, p.cfg.AllocateTimeout, factory, cmd)
+	p.ww = workerWatcher.NewSyncWorkerWatcher(p.allocator, p.cfg.NumWorkers, p.events)
+
+	workers, err := p.allocateWorkers(p.cfg.NumWorkers)
+	if err != nil {
+		return nil, errors.E(op, err)
+	}
+
+	// put stack in the pool
+	err = p.ww.AddToWatch(workers)
+	if err != nil {
+		return nil, errors.E(op, err)
+	}
+
+	p.errEncoder = defaultErrEncoder(p)
+
+	// if supervised config not nil, guess, that pool wanted to be supervised
+	if cfg.Supervisor != nil {
+		sp := supervisorWrapper(p, p.events, p.cfg.Supervisor)
+		// start watcher timer
+		sp.Start()
+		return sp, nil
+	}
+
+	return p, nil
+}
+
+func AddListeners(listeners ...events.Listener) Options {
+	return func(p *StaticPool) {
+		p.listeners = listeners
+		for i := 0; i < len(listeners); i++ {
+			p.addListener(listeners[i])
+		}
+	}
+}
+
+// AddListener connects event listener to the pool.
+func (sp *StaticPool) addListener(listener events.Listener) {
+	sp.events.AddListener(listener)
+}
+
+// Config returns associated pool configuration. Immutable.
+func (sp *StaticPool) GetConfig() interface{} {
+	return sp.cfg
+}
+
+// Workers returns worker list associated with the pool.
+func (sp *StaticPool) Workers() (workers []worker.SyncWorker) {
+	return sp.ww.WorkersList()
+}
+
+func (sp *StaticPool) RemoveWorker(wb worker.SyncWorker) error {
+	return sp.ww.RemoveWorker(wb)
+}
+
+// Be careful, sync Exec with ExecWithContext
+func (sp *StaticPool) Exec(p payload.Payload) (payload.Payload, error) {
+	const op = errors.Op("static_pool_exec")
+	if sp.cfg.Debug {
+		return sp.execDebug(p)
+	}
+	ctxGetFree, cancel := context.WithTimeout(context.Background(), sp.cfg.AllocateTimeout)
+	defer cancel()
+	w, err := sp.getWorker(ctxGetFree, op)
+	if err != nil {
+		return payload.Payload{}, errors.E(op, err)
+	}
+
+	rsp, err := w.Exec(p)
+	if err != nil {
+		return sp.errEncoder(err, w)
+	}
+
+	// worker want's to be terminated
+	// TODO careful with string(rsp.Context)
+	if len(rsp.Body) == 0 && string(rsp.Context) == StopRequest {
+		sp.stopWorker(w)
+
+		return sp.Exec(p)
+	}
+
+	err = sp.checkMaxJobs(w)
+	if err != nil {
+		return payload.Payload{}, errors.E(op, err)
+	}
+
+	return rsp, nil
+}
+
+// Be careful, sync with pool.Exec method
+func (sp *StaticPool) ExecWithContext(ctx context.Context, p payload.Payload) (payload.Payload, error) {
+	const op = errors.Op("static_pool_exec_with_context")
+	ctxGetFree, cancel := context.WithTimeout(ctx, sp.cfg.AllocateTimeout)
+	defer cancel()
+	w, err := sp.getWorker(ctxGetFree, op)
+	if err != nil {
+		return payload.Payload{}, errors.E(op, err)
+	}
+
+	rsp, err := w.ExecWithTimeout(ctx, p)
+	if err != nil {
+		return sp.errEncoder(err, w)
+	}
+
+	// worker want's to be terminated
+	if len(rsp.Body) == 0 && string(rsp.Context) == StopRequest {
+		sp.stopWorker(w)
+		return sp.ExecWithContext(ctx, p)
+	}
+
+	err = sp.checkMaxJobs(w)
+	if err != nil {
+		return payload.Payload{}, errors.E(op, err)
+	}
+
+	return rsp, nil
+}
+
+func (sp *StaticPool) stopWorker(w worker.SyncWorker) {
+	const op = errors.Op("static_pool_stop_worker")
+	w.State().Set(internal.StateInvalid)
+	err := w.Stop()
+	if err != nil {
+		sp.events.Push(events.WorkerEvent{Event: events.EventWorkerError, Worker: w, Payload: errors.E(op, err)})
+	}
+}
+
+// checkMaxJobs check for worker number of executions and kill workers if that number more than sp.cfg.MaxJobs
+func (sp *StaticPool) checkMaxJobs(w worker.SyncWorker) error {
+	const op = errors.Op("static_pool_check_max_jobs")
+	if sp.cfg.MaxJobs != 0 && w.State().NumExecs() >= sp.cfg.MaxJobs {
+		err := sp.ww.AllocateNew()
+		if err != nil {
+			return errors.E(op, err)
+		}
+	} else {
+		sp.ww.PushWorker(w)
+	}
+	return nil
+}
+
+func (sp *StaticPool) getWorker(ctxGetFree context.Context, op errors.Op) (worker.SyncWorker, error) {
+	// GetFreeWorker function consumes context with timeout
+	w, err := sp.ww.GetFreeWorker(ctxGetFree)
+	if err != nil {
+		// if the error is of kind NoFreeWorkers, it means, that we can't get worker from the stack during the allocate timeout
+		if errors.Is(errors.NoFreeWorkers, err) {
+			sp.events.Push(events.PoolEvent{Event: events.EventNoFreeWorkers, Payload: errors.E(op, err)})
+			return nil, errors.E(op, err)
+		}
+		// else if err not nil - return error
+		return nil, errors.E(op, err)
+	}
+	return w, nil
+}
+
+// Destroy all underlying stack (but let them to complete the task).
+func (sp *StaticPool) Destroy(ctx context.Context) {
+	sp.ww.Destroy(ctx)
+}
+
+func defaultErrEncoder(sp *StaticPool) ErrorEncoder {
+	return func(err error, w worker.SyncWorker) (payload.Payload, error) {
+		const op = errors.Op("error encoder")
+		// just push event if on any stage was timeout error
+		if errors.Is(errors.ExecTTL, err) {
+			sp.events.Push(events.PoolEvent{Event: events.EventExecTTL, Payload: errors.E(op, err)})
+		}
+		// soft job errors are allowed
+		if errors.Is(errors.SoftJob, err) {
+			if sp.cfg.MaxJobs != 0 && w.State().NumExecs() >= sp.cfg.MaxJobs {
+				err = sp.ww.AllocateNew()
+				if err != nil {
+					sp.events.Push(events.PoolEvent{Event: events.EventWorkerConstruct, Payload: errors.E(op, err)})
+				}
+
+				w.State().Set(internal.StateInvalid)
+				err = w.Stop()
+				if err != nil {
+					sp.events.Push(events.WorkerEvent{Event: events.EventWorkerError, Worker: w, Payload: errors.E(op, err)})
+				}
+			} else {
+				sp.ww.PushWorker(w)
+			}
+
+			return payload.Payload{}, errors.E(op, err)
+		}
+
+		w.State().Set(internal.StateInvalid)
+		sp.events.Push(events.PoolEvent{Event: events.EventWorkerDestruct, Payload: w})
+		errS := w.Stop()
+
+		if errS != nil {
+			return payload.Payload{}, errors.E(op, errors.Errorf("%v, %v", err, errS))
+		}
+
+		return payload.Payload{}, errors.E(op, err)
+	}
+}
+
+func (sp *StaticPool) newPoolAllocator(ctx context.Context, timeout time.Duration, factory transport.Factory, cmd func() *exec.Cmd) worker.Allocator {
+	return func() (*worker.SyncWorkerImpl, error) {
+		ctx, cancel := context.WithTimeout(ctx, timeout)
+		defer cancel()
+		w, err := factory.SpawnWorkerWithTimeout(ctx, cmd(), sp.listeners...)
+		if err != nil {
+			return nil, err
+		}
+
+		sw := worker.From(w)
+
+		sp.events.Push(events.PoolEvent{
+			Event:   events.EventWorkerConstruct,
+			Payload: sw,
+		})
+		return sw, nil
+	}
+}
+
+func (sp *StaticPool) execDebug(p payload.Payload) (payload.Payload, error) {
+	sw, err := sp.allocator()
+	if err != nil {
+		return payload.Payload{}, err
+	}
+
+	r, err := sw.Exec(p)
+
+	if stopErr := sw.Stop(); stopErr != nil {
+		sp.events.Push(events.WorkerEvent{Event: events.EventWorkerError, Worker: sw, Payload: err})
+	}
+
+	return r, err
+}
+
+// allocate required number of stack
+func (sp *StaticPool) allocateWorkers(numWorkers uint64) ([]worker.SyncWorker, error) {
+	const op = errors.Op("allocate workers")
+	var workers []worker.SyncWorker
+
+	// constant number of stack simplify logic
+	for i := uint64(0); i < numWorkers; i++ {
+		w, err := sp.allocator()
+		if err != nil {
+			return nil, errors.E(op, errors.WorkerAllocate, err)
+		}
+
+		workers = append(workers, w)
+	}
+	return workers, nil
+}