[VOL-3380] Functional area specific logging

Change-Id: I67414da013d8fc82827fcdb69d4f8a34040625d3
diff --git a/internal/pkg/swupg/adapter_download_manager.go b/internal/pkg/swupg/adapter_download_manager.go
new file mode 100755
index 0000000..64f5324
--- /dev/null
+++ b/internal/pkg/swupg/adapter_download_manager.go
@@ -0,0 +1,290 @@
+/*
+ * Copyright 2020-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//Package swupg provides the utilities for onu sw upgrade
+package swupg
+
+import (
+	"bufio"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/opencord/voltha-protos/v5/go/voltha"
+
+	"github.com/opencord/voltha-lib-go/v7/pkg/log"
+)
+
+// ### downloadToAdapter related definitions  ####
+
+//not yet defined to go with sca..., later also some configure options ??
+//const defaultDownloadTimeout = 60 // (?) Seconds
+//const localImgPath = "/home/lcui/work/tmp"
+
+// ### downloadToAdapter  			    - end ####
+
+//AdapterDownloadManager structure holds information needed for downloading to and storing images within the adapter
+type AdapterDownloadManager struct {
+	mutexDownloadImageDsc sync.RWMutex
+	downloadImageDscSlice []*voltha.ImageDownload
+}
+
+//NewAdapterDownloadManager constructor returns a new instance of a AdapterDownloadManager
+//mib_db (as well as not inluded alarm_db not really used in this code? VERIFY!!)
+func NewAdapterDownloadManager(ctx context.Context) *AdapterDownloadManager {
+	logger.Debug(ctx, "init-AdapterDownloadManager")
+	var localDnldMgr AdapterDownloadManager
+	localDnldMgr.downloadImageDscSlice = make([]*voltha.ImageDownload, 0)
+	return &localDnldMgr
+}
+
+//ImageExists returns true if the requested image already exists within the adapter
+func (dm *AdapterDownloadManager) ImageExists(ctx context.Context, apImageDsc *voltha.ImageDownload) bool {
+	logger.Debugw(ctx, "checking on existence of the image", log.Fields{"image-name": (*apImageDsc).Name})
+	dm.mutexDownloadImageDsc.RLock()
+	defer dm.mutexDownloadImageDsc.RUnlock()
+
+	for _, pDnldImgDsc := range dm.downloadImageDscSlice {
+		if (*pDnldImgDsc).Name == (*apImageDsc).Name {
+			//image found (by name)
+			return true
+		}
+	}
+	//image not found (by name)
+	return false
+}
+
+//ImageLocallyDownloaded returns true if the requested image already exists within the adapter
+func (dm *AdapterDownloadManager) ImageLocallyDownloaded(ctx context.Context, apImageDsc *voltha.ImageDownload) bool {
+	logger.Debugw(ctx, "checking if image is fully downloaded", log.Fields{"image-name": (*apImageDsc).Name})
+	dm.mutexDownloadImageDsc.RLock()
+	defer dm.mutexDownloadImageDsc.RUnlock()
+
+	for _, pDnldImgDsc := range dm.downloadImageDscSlice {
+		if (*pDnldImgDsc).Name == (*apImageDsc).Name {
+			//image found (by name)
+			if (*pDnldImgDsc).DownloadState == voltha.ImageDownload_DOWNLOAD_SUCCEEDED {
+				logger.Debugw(ctx, "image has been fully downloaded", log.Fields{"image-name": (*apImageDsc).Name})
+				return true
+			}
+			logger.Debugw(ctx, "image not yet fully downloaded", log.Fields{"image-name": (*apImageDsc).Name})
+			return false
+		}
+	}
+	//image not found (by name)
+	logger.Errorw(ctx, "image does not exist", log.Fields{"image-name": (*apImageDsc).Name})
+	return false
+}
+
+//StartDownload returns true if the download of the requested image could be started
+func (dm *AdapterDownloadManager) StartDownload(ctx context.Context, apImageDsc *voltha.ImageDownload) error {
+	if apImageDsc.LocalDir != "" {
+		logger.Infow(ctx, "image download-to-adapter requested", log.Fields{
+			"image-path": apImageDsc.LocalDir, "image-name": apImageDsc.Name})
+		newImageDscPos := len(dm.downloadImageDscSlice)
+		dm.downloadImageDscSlice = append(dm.downloadImageDscSlice, apImageDsc)
+		dm.downloadImageDscSlice[newImageDscPos].DownloadState = voltha.ImageDownload_DOWNLOAD_STARTED
+		//try to download from http
+		urlName := apImageDsc.Url + "/" + apImageDsc.Name
+		err := dm.downloadFile(ctx, urlName, apImageDsc.LocalDir, apImageDsc.Name)
+		if err != nil {
+			return (err)
+		}
+		//return success to comfort the core processing during integration
+		return nil
+	}
+	// we can use the missing local path temporary also to test some failure behavior (system reation on failure)
+	// with updated control API's or at some adequate time we could also set some defined fixed localPath internally
+	logger.Errorw(ctx, "could not start download: no valid local directory to write to", log.Fields{"image-name": (*apImageDsc).Name})
+	return errors.New("could not start download: no valid local directory to write to")
+}
+
+//downloadFile downloads the specified file from the given http location
+func (dm *AdapterDownloadManager) downloadFile(ctx context.Context, aURLName string, aFilePath string, aFileName string) error {
+	// Get the data
+	logger.Infow(ctx, "downloading from http", log.Fields{"url": aURLName, "localPath": aFilePath})
+	// http command is already part of the aURLName argument
+	urlBase, err1 := url.Parse(aURLName)
+	if err1 != nil {
+		logger.Errorw(ctx, "could not set base url command", log.Fields{"url": aURLName, "error": err1})
+		return fmt.Errorf("could not set base url command: %s, error: %s", aURLName, err1)
+	}
+	urlParams := url.Values{}
+	urlBase.RawQuery = urlParams.Encode()
+
+	//pre-check on file existence
+	reqExist, errExist2 := http.NewRequest("HEAD", urlBase.String(), nil)
+	if errExist2 != nil {
+		logger.Errorw(ctx, "could not generate http head request", log.Fields{"url": urlBase.String(), "error": errExist2})
+		return fmt.Errorf("could not  generate http head request: %s, error: %s", aURLName, errExist2)
+	}
+	ctxExist, cancelExist := context.WithDeadline(ctx, time.Now().Add(3*time.Second)) //waiting for some fast answer
+	defer cancelExist()
+	_ = reqExist.WithContext(ctxExist)
+	respExist, errExist3 := http.DefaultClient.Do(reqExist)
+	if errExist3 != nil || (respExist != nil && respExist.StatusCode != http.StatusOK) {
+		if respExist != nil {
+			logger.Errorw(ctx, "could not http head from url", log.Fields{"url": urlBase.String(),
+				"error": errExist3, "status": respExist.StatusCode})
+			//if head is not supported by server we cannot use this test and just try to continue
+			if respExist.StatusCode != http.StatusMethodNotAllowed {
+				logger.Errorw(ctx, "http head from url: file does not exist here, aborting", log.Fields{"url": urlBase.String(),
+					"error": errExist3, "status": respExist.StatusCode})
+				return fmt.Errorf("http head from url: file does not exist here, aborting: %s, error: %s, status: %d",
+					aURLName, errExist2, respExist.StatusCode)
+			}
+		} else {
+			logger.Errorw(ctx, "could not http head from url", log.Fields{"url": urlBase.String(),
+				"error": errExist3})
+		}
+	}
+
+	if errExist3 == nil && respExist != nil {
+		defer func() {
+			deferredErr := respExist.Body.Close()
+			if deferredErr != nil {
+				logger.Errorw(ctx, "error at closing http head response body", log.Fields{"url": urlBase.String(), "error": deferredErr})
+			}
+		}()
+	}
+
+	//trying to download - do it in background as it may take some time ...
+	go dm.requestDownload(ctx, urlBase, aFilePath, aFileName)
+	return nil
+}
+
+func (dm *AdapterDownloadManager) requestDownload(ctx context.Context, urlBase *url.URL, aFilePath, aFileName string) {
+	req, err2 := http.NewRequest("GET", urlBase.String(), nil)
+	if err2 != nil {
+		logger.Errorw(ctx, "could not generate http request", log.Fields{"url": urlBase.String(), "error": err2})
+		return
+	}
+	ctx, cancel := context.WithDeadline(ctx, time.Now().Add(10*time.Second)) //long timeout for remote server and big file
+	defer cancel()
+	_ = req.WithContext(ctx)
+	resp, err3 := http.DefaultClient.Do(req)
+	if err3 != nil {
+		logger.Errorw(ctx, "could not http get from url", log.Fields{"url": urlBase.String(), "error": err3})
+		return
+	}
+	defer func() {
+		deferredErr := resp.Body.Close()
+		if deferredErr != nil {
+			logger.Errorw(ctx, "error at closing http get response body", log.Fields{"url": urlBase.String(), "error": deferredErr})
+		}
+	}()
+
+	if resp.StatusCode != http.StatusOK {
+		logger.Errorw(ctx, "could not http get from url", log.Fields{"url": urlBase.String(), "status": resp.StatusCode})
+		return
+	}
+
+	// Create the file
+	aLocalPathName := aFilePath + "/" + aFileName
+	file, err := os.Create(aLocalPathName)
+	if err != nil {
+		logger.Errorw(ctx, "could not create local file", log.Fields{"path_file": aLocalPathName, "error": err})
+		return
+	}
+	defer func() {
+		deferredErr := file.Close()
+		if deferredErr != nil {
+			logger.Errorw(ctx, "error at closing new file", log.Fields{"path_file": aLocalPathName, "error": deferredErr})
+		}
+	}()
+
+	// Write the body to file
+	_, err = io.Copy(file, resp.Body)
+	if err != nil {
+		logger.Errorw(ctx, "could not copy file content", log.Fields{"url": urlBase.String(), "file": aLocalPathName, "error": err})
+		return
+	}
+
+	fileStats, statsErr := file.Stat()
+	if statsErr != nil {
+		logger.Errorw(ctx, "created file can't be accessed", log.Fields{"file": aLocalPathName, "stat-error": statsErr})
+	}
+	if fileStats != nil {
+		logger.Infow(ctx, "written file size is", log.Fields{"file": aLocalPathName, "length": fileStats.Size()})
+	}
+
+	for _, pDnldImgDsc := range dm.downloadImageDscSlice {
+		if (*pDnldImgDsc).Name == aFileName {
+			//image found (by name)
+			(*pDnldImgDsc).DownloadState = voltha.ImageDownload_DOWNLOAD_SUCCEEDED
+			return //can leave directly
+		}
+	}
+}
+
+//getImageBufferLen returns the length of the specified file in bytes (file size)
+func (dm *AdapterDownloadManager) getImageBufferLen(ctx context.Context, aFileName string,
+	aLocalPath string) (int64, error) {
+	//maybe we can also use FileSize from dm.downloadImageDscSlice - future option?
+
+	file, err := os.Open(filepath.Clean(aLocalPath + "/" + aFileName))
+	if err != nil {
+		return 0, err
+	}
+	defer func() {
+		err := file.Close()
+		if err != nil {
+			logger.Errorw(ctx, "failed to close file", log.Fields{"error": err})
+		}
+	}()
+
+	stats, statsErr := file.Stat()
+	if statsErr != nil {
+		return 0, statsErr
+	}
+
+	return stats.Size(), nil
+}
+
+//getDownloadImageBuffer returns the content of the requested file as byte slice
+func (dm *AdapterDownloadManager) getDownloadImageBuffer(ctx context.Context, aFileName string,
+	aLocalPath string) ([]byte, error) {
+	file, err := os.Open(filepath.Clean(aLocalPath + "/" + aFileName))
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		err := file.Close()
+		if err != nil {
+			logger.Errorw(ctx, "failed to close file", log.Fields{"error": err})
+		}
+	}()
+
+	stats, statsErr := file.Stat()
+	if statsErr != nil {
+		return nil, statsErr
+	}
+
+	var size int64 = stats.Size()
+	bytes := make([]byte, size)
+
+	buffer := bufio.NewReader(file)
+	_, err = buffer.Read(bytes)
+
+	return bytes, err
+}