rename all remaining packages to internal/ (#12418)

This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`

internal/event/target/store.go

@@ -0,0 +1,144 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package target
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/minio/minio/internal/event"
+)
+
+const retryInterval = 3 * time.Second
+
+// errNotConnected - indicates that the target connection is not active.
+var errNotConnected = errors.New("not connected to target server/service")
+
+// errLimitExceeded error is sent when the maximum limit is reached.
+var errLimitExceeded = errors.New("the maximum store limit reached")
+
+// Store - To persist the events.
+type Store interface {
+	Put(event event.Event) error
+	Get(key string) (event.Event, error)
+	List() ([]string, error)
+	Del(key string) error
+	Open() error
+}
+
+// replayEvents - Reads the events from the store and replays.
+func replayEvents(store Store, doneCh <-chan struct{}, loggerOnce func(ctx context.Context, err error, id interface{}, kind ...interface{}), id event.TargetID) <-chan string {
+	eventKeyCh := make(chan string)
+
+	go func() {
+		retryTicker := time.NewTicker(retryInterval)
+		defer retryTicker.Stop()
+		defer close(eventKeyCh)
+		for {
+			names, err := store.List()
+			if err == nil {
+				for _, name := range names {
+					select {
+					case eventKeyCh <- strings.TrimSuffix(name, eventExt):
+						// Get next key.
+					case <-doneCh:
+						return
+					}
+				}
+			}
+
+			if len(names) < 2 {
+				select {
+				case <-retryTicker.C:
+					if err != nil {
+						loggerOnce(context.Background(),
+							fmt.Errorf("store.List() failed '%w'", err), id)
+					}
+				case <-doneCh:
+					return
+				}
+			}
+		}
+	}()
+
+	return eventKeyCh
+}
+
+// IsConnRefusedErr - To check fot "connection refused" error.
+func IsConnRefusedErr(err error) bool {
+	return errors.Is(err, syscall.ECONNREFUSED)
+}
+
+// IsConnResetErr - Checks for connection reset errors.
+func IsConnResetErr(err error) bool {
+	if strings.Contains(err.Error(), "connection reset by peer") {
+		return true
+	}
+	// incase if error message is wrapped.
+	return errors.Is(err, syscall.ECONNRESET)
+}
+
+// sendEvents - Reads events from the store and re-plays.
+func sendEvents(target event.Target, eventKeyCh <-chan string, doneCh <-chan struct{}, loggerOnce func(ctx context.Context, err error, id interface{}, kind ...interface{})) {
+	retryTicker := time.NewTicker(retryInterval)
+	defer retryTicker.Stop()
+
+	send := func(eventKey string) bool {
+		for {
+			err := target.Send(eventKey)
+			if err == nil {
+				break
+			}
+
+			if err != errNotConnected && !IsConnResetErr(err) {
+				loggerOnce(context.Background(),
+					fmt.Errorf("target.Send() failed with '%w'", err),
+					target.ID())
+			}
+
+			// Retrying after 3secs back-off
+
+			select {
+			case <-retryTicker.C:
+			case <-doneCh:
+				return false
+			}
+		}
+		return true
+	}
+
+	for {
+		select {
+		case eventKey, ok := <-eventKeyCh:
+			if !ok {
+				// closed channel.
+				return
+			}
+
+			if !send(eventKey) {
+				return
+			}
+		case <-doneCh:
+			return
+		}
+	}
+}