Work in progress rearchitecture to use interfaces; currently pointers are screwy causing segfaults

1 files changed, 250 insertions, 102 deletions

diff --git a/pipelinepreprocess/main.go b/pipelinepreprocess/main.go
index 6c58d98..c075fa9 100644
--- a/pipelinepreprocess/main.go
+++ b/pipelinepreprocess/main.go
@@ -6,6 +6,8 @@ package main
 // TODO: check if images are prebinarised and if so skip multiple binarisation
 
 import (
+	"errors"
+	"fmt"
 	"log"
 	"os"
 	"path/filepath"
@@ -28,7 +30,8 @@ type NullWriter bool
 func (w NullWriter) Write(p []byte) (n int, err error) {
 	return len(p), nil
 }
-var verboselog *log.Logger
+
+var alreadydone *regexp.Regexp
 
 const HeartbeatTime = 60
 const PauseBetweenChecks = 60 * time.Second
@@ -44,20 +47,225 @@ const PreprocPattern = `_bin[0-9].[0-9].png`
 //
 // TODO: consider having the download etc functions return a channel like a generator, like in rob pike's talk
 
-func download(dl chan string, pre chan string, downloader *s3manager.Downloader, dir string) {
-	for key := range dl {
-		verboselog.Println("Downloading", key)
-		fn := filepath.Join(dir, filepath.Base(key))
-		f, err := os.Create(fn)
+type Clouder interface {
+	Init() error
+	ListObjects(bucket string, prefix string, names chan string) error
+	Download(bucket string, key string, fn string) error
+	Upload(bucket string, key string, path string) error
+	CheckQueue(url string) (qmsg, error)
+	AddToQueue(url string, msg string) error
+	DelFromQueue(url string, handle string) error
+	QueueHeartbeat(t *time.Ticker, msgHandle string, qurl string) error
+}
+
+type Pipeliner interface {
+	Clouder
+	ListInProgress(bookname string, names chan string) error
+	DownloadFromInProgress(key string, fn string) error
+	UploadToInProgress(key string, path string) error
+	CheckPreQueue() (qmsg, error)
+	AddToOCRQueue(msg string) error
+	DelFromPreQueue(handle string) error
+	PreQueueHeartbeat(t *time.Ticker, msgHandle string) error
+}
+
+type qmsg struct {
+	Handle, Body string
+}
+
+type awsConn struct {
+	// these need to be set before running Init()
+	region string
+	logger *log.Logger
+
+	// these are used internally
+	sess *session.Session
+        s3svc *s3.S3
+        sqssvc *sqs.SQS
+        downloader *s3manager.Downloader
+	uploader *s3manager.Uploader
+	prequrl, ocrqurl string
+}
+
+func (a awsConn) Init() error {
+	if a.region == "" {
+		return errors.New("No region set")
+	}
+	if a.logger == nil {
+		return errors.New("No logger set")
+	}
+
+	var err error
+	a.sess, err = session.NewSession(&aws.Config{
+		Region: aws.String(a.region),
+	})
+	if err != nil {
+		return errors.New(fmt.Sprintf("Failed to set up aws session: %s", err))
+	}
+	a.s3svc = s3.New(a.sess)
+	a.sqssvc = sqs.New(a.sess)
+	a.downloader = s3manager.NewDownloader(a.sess)
+	a.uploader = s3manager.NewUploader(a.sess)
+
+        a.logger.Println("Getting preprocess queue URL")
+        result, err := a.sqssvc.GetQueueUrl(&sqs.GetQueueUrlInput{
+                QueueName: aws.String("rescribepreprocess"),
+        })
+        if err != nil {
+                return errors.New(fmt.Sprintf("Error getting preprocess queue URL: %s", err))
+        }
+        a.prequrl = *result.QueueUrl
+        a.logger.Println("preprocess queue URL", a.prequrl)
+
+        a.logger.Println("Getting OCR queue URL")
+        result, err = a.sqssvc.GetQueueUrl(&sqs.GetQueueUrlInput{
+                QueueName: aws.String("rescribeocr"),
+        })
+        if err != nil {
+                return errors.New(fmt.Sprintf("Error getting OCR queue URL: %s", err))
+        }
+        a.ocrqurl = *result.QueueUrl
+	return nil
+}
+
+func (a awsConn) CheckQueue(url string) (qmsg, error) {
+	msgResult, err := a.sqssvc.ReceiveMessage(&sqs.ReceiveMessageInput{
+		MaxNumberOfMessages: aws.Int64(1),
+		VisibilityTimeout: aws.Int64(HeartbeatTime * 2),
+		WaitTimeSeconds: aws.Int64(20),
+		QueueUrl: &url,
+	})
+	if err != nil {
+		return qmsg{}, err
+	}
+
+	if len(msgResult.Messages) > 0 {
+		msg := qmsg{ Handle: *msgResult.Messages[0].ReceiptHandle, Body: *msgResult.Messages[0].Body }
+		a.logger.Println("Message received:", msg.Body)
+		return msg, nil
+	} else {
+		return qmsg{}, nil
+	}
+}
+
+func (a awsConn) CheckPreQueue() (qmsg, error) {
+	a.logger.Println("Checking preprocessing queue for new messages:", a.prequrl)
+	return a.CheckQueue(a.prequrl)
+}
+
+func (a awsConn) QueueHeartbeat(t *time.Ticker, msgHandle string, qurl string) error {
+	for _ = range t.C {
+		duration := int64(HeartbeatTime * 2)
+		_, err := a.sqssvc.ChangeMessageVisibility(&sqs.ChangeMessageVisibilityInput{
+			ReceiptHandle: &msgHandle,
+			QueueUrl: &qurl,
+			VisibilityTimeout: &duration,
+		})
 		if err != nil {
-			log.Fatalln("Failed to create file", fn, err)
+			return errors.New(fmt.Sprintf("Heartbeat error updating queue duration: %s", err))
 		}
-		defer f.Close()
+	}
+	return nil
+}
+
+func (a awsConn) PreQueueHeartbeat(t *time.Ticker, msgHandle string) error {
+	a.logger.Println("Starting preprocess queue heartbeat for", msgHandle)
+	return a.QueueHeartbeat(t, msgHandle, a.prequrl)
+}
+
+func (a awsConn) ListObjects(bucket string, prefix string, names chan string) error {
+	err := a.s3svc.ListObjectsV2Pages(&s3.ListObjectsV2Input{
+		Bucket: aws.String(bucket),
+		Prefix: aws.String(prefix),
+	}, func(page *s3.ListObjectsV2Output, last bool) bool {
+		for _, r := range page.Contents {
+			if alreadydone.MatchString(*r.Key) {
+				a.logger.Println("Skipping item that looks like it has already been processed", *r.Key)
+				continue
+			}
+			names <- *r.Key
+		}
+		return true
+	})
+	close(names)
+	return err
+}
+
+func (a awsConn) ListInProgress(bookname string, names chan string) error {
+	return a.ListObjects("rescribeinprogress", bookname, names)
+}
+
+func (a awsConn) AddToQueue(url string, msg string) error {
+	_, err := a.sqssvc.SendMessage(&sqs.SendMessageInput{
+		MessageBody: &msg,
+		QueueUrl: &url,
+	})
+	return err
+}
+
+func (a awsConn) AddToOCRQueue(msg string) error {
+	return a.AddToQueue(a.ocrqurl, msg)
+}
 
-		_, err = downloader.Download(f,
-			&s3.GetObjectInput{
-				Bucket: aws.String("rescribeinprogress"),
-				Key: &key })
+func (a awsConn) DelFromQueue(url string, handle string) error {
+	_, err := a.sqssvc.DeleteMessage(&sqs.DeleteMessageInput{
+		QueueUrl: &url,
+		ReceiptHandle: &handle,
+	})
+	return err
+}
+
+func (a awsConn) DelFromPreQueue(handle string) error {
+	return a.DelFromQueue(a.prequrl, handle)
+}
+
+func (a awsConn) Download(bucket string, key string, path string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	_, err = a.downloader.Download(f,
+		&s3.GetObjectInput{
+			Bucket: aws.String(bucket),
+			Key: &key,
+	})
+	return err
+}
+
+func (a awsConn) DownloadFromInProgress(key string, path string) error {
+	a.logger.Println("Downloading", key)
+	return a.Download("rescribeinprogress", key, path)
+}
+
+func (a awsConn) Upload(bucket string, key string, path string) error {
+	file, err := os.Open(path)
+	if err != nil {
+		log.Fatalln("Failed to open file", path, err)
+	}
+	defer file.Close()
+
+	_, err = a.uploader.Upload(&s3manager.UploadInput{
+		Bucket: aws.String(bucket),
+		Key:    aws.String(key),
+		Body:   file,
+	})
+	return err
+}
+
+func (a awsConn) UploadToInProgress(key string, path string) error {
+	a.logger.Println("Uploading", path)
+	return a.Upload("rescribeinprogress", key, path)
+}
+
+
+
+
+func download(dl chan string, pre chan string, conn Pipeliner, dir string) {
+	for key := range dl {
+		fn := filepath.Join(dir, filepath.Base(key))
+		err := conn.DownloadFromInProgress(key, fn)
 		if err != nil {
 			log.Fatalln("Failed to download", key, err)
 		}
@@ -66,9 +274,9 @@ func download(dl chan string, pre chan string, downloader *s3manager.Downloader,
 	close(pre)
 }
 
-func preprocess(pre chan string, up chan string) {
+func preprocess(pre chan string, up chan string, logger *log.Logger) {
 	for path := range pre {
-		verboselog.Println("Preprocessing", path)
+		logger.Println("Preprocessing", path)
 		done, err := preproc.PreProcMulti(path, []float64{0.1, 0.2, 0.4, 0.5}, "binary", 0, true, 5, 30)
 		if err != nil {
 			log.Fatalln("Error preprocessing", path, err)
@@ -80,21 +288,11 @@ func preprocess(pre chan string, up chan string) {
 	close(up)
 }
 
-func up(c chan string, done chan bool, uploader *s3manager.Uploader, bookname string) {
+func up(c chan string, done chan bool, conn Pipeliner, bookname string) {
 	for path := range c {
-		verboselog.Println("Uploading", path)
 		name := filepath.Base(path)
-		file, err := os.Open(path)
-		if err != nil {
-			log.Fatalln("Failed to open file", path, err)
-		}
-		defer file.Close()
-
-		_, err = uploader.Upload(&s3manager.UploadInput{
-			Bucket: aws.String("rescribeinprogress"),
-			Key:    aws.String(filepath.Join(bookname, name)),
-			Body:   file,
-		})
+		key := filepath.Join(bookname, name)
+		err := conn.UploadToInProgress(key, path)
 		if err != nil {
 			log.Fatalln("Failed to upload", path, err)
 		}
@@ -118,6 +316,7 @@ func heartbeat(h *time.Ticker, msgHandle string, qurl string, sqssvc *sqs.SQS) {
 }
 
 func main() {
+	var verboselog *log.Logger
 	if len(os.Args) > 1 {
 		if os.Args[1] == "-v" {
 			verboselog = log.New(os.Stdout, "", log.LstdFlags)
@@ -129,65 +328,31 @@ func main() {
 		verboselog = log.New(n, "", log.LstdFlags)
 	}
 
-	alreadydone := regexp.MustCompile(PreprocPattern)
+	alreadydone = regexp.MustCompile(PreprocPattern)
 
-	verboselog.Println("Setting up AWS session")
-	sess, err := session.NewSession(&aws.Config{
-		Region: aws.String("eu-west-2"),
-	})
-	if err != nil {
-		log.Fatalln("Error: failed to set up aws session:", err)
-	}
-	s3svc := s3.New(sess)
-	sqssvc := sqs.New(sess)
-	downloader := s3manager.NewDownloader(sess)
-	uploader := s3manager.NewUploader(sess)
-
-	preqname := "rescribepreprocess"
-	verboselog.Println("Getting Queue URL for", preqname)
-	result, err := sqssvc.GetQueueUrl(&sqs.GetQueueUrlInput{
-		QueueName: aws.String(preqname),
-	})
-	if err != nil {
-		log.Fatalln("Error getting queue URL for", preqname, ":", err)
-	}
-	prequrl := *result.QueueUrl
+	var conn Pipeliner
+	conn = awsConn{ region: "eu-west-2", logger: verboselog }
 
-	ocrqname := "rescribeocr"
-	verboselog.Println("Getting Queue URL for", ocrqname)
-	result, err = sqssvc.GetQueueUrl(&sqs.GetQueueUrlInput{
-		QueueName: aws.String(ocrqname),
-	})
+	verboselog.Println("Setting up AWS session")
+	err := conn.Init()
 	if err != nil {
-		log.Fatalln("Error getting queue URL for", ocrqname, ":", err)
+		log.Fatalln("Error setting up cloud connection:", err)
 	}
-	ocrqurl := *result.QueueUrl
 
 	for {
-		verboselog.Println("Checking preprocessing queue for new messages")
-		msgResult, err := sqssvc.ReceiveMessage(&sqs.ReceiveMessageInput{
-			MaxNumberOfMessages: aws.Int64(1),
-			VisibilityTimeout: aws.Int64(HeartbeatTime * 2),
-			WaitTimeSeconds: aws.Int64(20),
-			QueueUrl: &prequrl,
-		})
+		msg, err := conn.CheckPreQueue()
 		if err != nil {
-			log.Fatalln("Error checking queue", preqname, ":", err)
+			log.Fatalln("Error checking preprocess queue", err)
 		}
-
-		var bookname string
-		if len(msgResult.Messages) > 0 {
-			bookname = *msgResult.Messages[0].Body
-			verboselog.Println("Message received:", bookname)
-		} else {
+		if msg.Handle == "" {
 			verboselog.Println("No message received, sleeping")
 			time.Sleep(PauseBetweenChecks)
 			continue
 		}
+		bookname := msg.Body
 
-		verboselog.Println("Starting heartbeat every", HeartbeatTime, "seconds")
 		t := time.NewTicker(HeartbeatTime * time.Second)
-		go heartbeat(t, *msgResult.Messages[0].ReceiptHandle, prequrl, sqssvc)
+		go conn.PreQueueHeartbeat(t, msg.Handle)
 
 
 		d := filepath.Join(os.TempDir(), bookname)
@@ -202,49 +367,32 @@ func main() {
 		done := make(chan bool) // this is just to communicate when up has finished, so the queues can be updated
 
 		// these functions will do their jobs when their channels have data
-		go download(dl, pre, downloader, d)
-		go preprocess(pre, upc)
-		go up(upc, done, uploader, bookname)
+		go download(dl, pre, conn, d)
+		go preprocess(pre, upc, verboselog)
+		go up(upc, done, conn, bookname)
 
 
 		verboselog.Println("Getting list of objects to download")
-		err = s3svc.ListObjectsV2Pages(&s3.ListObjectsV2Input{
-			Bucket: aws.String("rescribeinprogress"),
-			Prefix: aws.String(bookname),
-		}, func(page *s3.ListObjectsV2Output, last bool) bool {
-			for _, r := range page.Contents {
-				if alreadydone.MatchString(*r.Key) {
-					verboselog.Println("Skipping item that looks like it has already been processed", *r.Key)
-					continue
-				}
-				dl <- *r.Key
-			}
-			return true
-		})
-		close(dl)
-
+		err = conn.ListInProgress(bookname, dl)
+		if err != nil {
+			log.Fatalln("Failed to get list of files for book", bookname, err)
+		}
 
 		// wait for the done channel to be posted to
 		<-done
 
-		verboselog.Println("Sending", bookname, "to queue", ocrqurl)
-		_, err = sqssvc.SendMessage(&sqs.SendMessageInput{
-			MessageBody: aws.String(bookname),
-			QueueUrl: &ocrqurl,
-		})
+		verboselog.Println("Sending", bookname, "to OCR queue")
+		err = conn.AddToOCRQueue(bookname)
 		if err != nil {
-			log.Fatalln("Error sending message to queue", ocrqname, ":", err)
+			log.Fatalln("Error adding to ocr queue", bookname, err)
 		}
 
 		t.Stop()
 
-		verboselog.Println("Deleting original message from queue", prequrl)
-		_, err = sqssvc.DeleteMessage(&sqs.DeleteMessageInput{
-			QueueUrl: &prequrl,
-			ReceiptHandle: msgResult.Messages[0].ReceiptHandle,
-		})
+		verboselog.Println("Deleting original message from preprocessing queue")
+		err = conn.DelFromPreQueue(msg.Handle)
 		if err != nil {
-			log.Fatalln("Error deleting message from queue", preqname, ":", err)
+			log.Fatalln("Error deleting message from preprocessing queue", err)
 		}
 
 		err = os.RemoveAll(d)