From ae9ceb51691d21911baffde7eb11b105f27621c8 Mon Sep 17 00:00:00 2001
From: DanB <danb@cgrates.org>
Date: Tue, 20 Mar 2018 18:35:21 +0100
Subject: [PATCH] Basic loaders skel

---
 loaders/loader.go  | 102 +++++++++++++++++++++++++++++++++++++++++++++
 loaders/loaders.go |  24 +++++++++++
 utils/consts.go    |   1 +
 3 files changed, 127 insertions(+)
 create mode 100644 loaders/loader.go
 create mode 100644 loaders/loaders.go

diff --git a/loaders/loader.go b/loaders/loader.go
new file mode 100644
index 000000000..84cac5a74
--- /dev/null
+++ b/loaders/loader.go
@@ -0,0 +1,102 @@
+/*
+Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
+Copyright (C) ITsysCOM GmbH
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+package loaders
+
+import (
+	"encoding/csv"
+	"fmt"
+	"os"
+	"path"
+
+	"github.com/cgrates/cgrates/config"
+	"github.com/cgrates/cgrates/utils"
+)
+
+type openedCSVFile struct {
+	fileName string
+	fd       *os.File
+	csvRdr   *csv.Reader
+}
+
+// Loader is one instance loading from a folder
+type Loader struct {
+	tpInDir      string
+	tpOutDir     string
+	lockFilename string
+	cacheSConns  []*config.HaPoolConfig
+	fieldSep     string
+	dataTpls     []*config.LoaderSDataType
+	rdrs         map[string]map[string]*openedCSVFile // map[loaderType]map[fileName]*openedCSVFile for common incremental read
+}
+
+// lockFolder will attempt to lock the folder by creating the lock file
+func (ldr *Loader) lockFolder() (err error) {
+	_, err = os.OpenFile(path.Join(ldr.tpInDir, ldr.lockFilename),
+		os.O_RDONLY|os.O_CREATE, 0644)
+	return
+}
+
+func (ldr *Loader) unlockFolder() (err error) {
+	return os.Remove(path.Join(ldr.tpInDir,
+		ldr.lockFilename))
+}
+
+// ProcessFolder will process the content in the folder with locking
+func (ldr *Loader) ProcessFolder() (err error) {
+	if err = ldr.lockFolder(); err != nil {
+		return
+	}
+	defer ldr.unlockFolder()
+	for loaderType := range ldr.rdrs {
+		switch loaderType {
+		case utils.MetaAttributes:
+			if err = ldr.processAttributes(); err != nil {
+				utils.Logger.Warning(fmt.Sprintf("<%s> loaderType: <%s>, err: %s",
+					utils.LoaderS, loaderType, err.Error()))
+			}
+		default:
+			utils.Logger.Warning(fmt.Sprintf("<%s> unsupported loaderType: <%s>",
+				utils.LoaderS, loaderType))
+		}
+	}
+	return
+}
+
+// unreferenceFile will cleanup an used file by closing and removing from referece map
+func (ldr *Loader) unreferenceFile(loaderType, fileName string) (err error) {
+	openedCSVFile := ldr.rdrs[loaderType][fileName]
+	ldr.rdrs[loaderType][fileName] = nil
+	return openedCSVFile.fd.Close()
+}
+
+// processAttributes contains the procedure for loading Attributes
+func (ldr *Loader) processAttributes() (err error) {
+	// open files as csv readers
+	for fName := range ldr.rdrs[utils.MetaAttributes] {
+		var fd *os.File
+		if fd, err = os.Open(path.Join(ldr.tpInDir, fName)); err != nil {
+			return err
+		}
+		ldr.rdrs[utils.MetaAttributes][fName] = &openedCSVFile{
+			fileName: fName, fd: fd, csvRdr: csv.NewReader(fd)}
+		defer ldr.unreferenceFile(utils.MetaAttributes, fName)
+	}
+	// start processing lines
+	return
+}
diff --git a/loaders/loaders.go b/loaders/loaders.go
new file mode 100644
index 000000000..3043b3668
--- /dev/null
+++ b/loaders/loaders.go
@@ -0,0 +1,24 @@
+/*
+Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
+Copyright (C) ITsysCOM GmbH
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+package loaders
+
+// LoaderS is the Loader service handling independent Loaders
+type LoaderS struct {
+	loaders map[string]*Loader
+}
diff --git a/utils/consts.go b/utils/consts.go
index fd64012ed..30d5faace 100755
--- a/utils/consts.go
+++ b/utils/consts.go
@@ -529,6 +529,7 @@ const (
 	Substitute                   = "Substitute"
 	Append                       = "Append"
 	MetaRound                    = "*round"
+	LoaderS                      = "LoaderS"
 )
 
 //MetaMetrics