In-file memory queue! No more insane RAM consumption

.gitignore

@@ -7,4 +7,5 @@ conf_mega_ita.json
 wecr
 release/
 scraped/
-extracted_data.txt
+extracted_data.txt
+visit_queue.tmp

src/config/config.go

@@ -71,6 +71,7 @@ type Conf struct {
 	InitialPages       []string `json:"initial_pages"`
 	AllowedDomains     []string `json:"allowed_domains"`
 	BlacklistedDomains []string `json:"blacklisted_domains"`
+	InMemoryVisitQueue bool     `json:"in_memory_visit_queue"`
 	Save               Save     `json:"save"`
 	Logging            Logging  `json:"logging"`
 }
@@ -98,6 +99,7 @@ func Default() *Conf {
 		Workers:            20,
 		AllowedDomains:     []string{""},
 		BlacklistedDomains: []string{""},
+		InMemoryVisitQueue: false,
 		Logging: Logging{
 			OutputLogs: true,
 			LogsFile:   "logs.log",

src/main.go

@@ -33,6 +33,7 @@ import (
 	"time"
 	"unbewohnte/wecr/config"
 	"unbewohnte/wecr/logger"
+	"unbewohnte/wecr/queue"
 	"unbewohnte/wecr/utilities"
 	"unbewohnte/wecr/web"
 	"unbewohnte/wecr/worker"
@@ -335,20 +336,19 @@ func main() {
 		}
 		defer func() {
 			visitQueueFile.Close()
-			// os.Remove(filepath.Join(workingDirectory, defaultVisitQueueFile))
+			os.Remove(filepath.Join(workingDirectory, defaultVisitQueueFile))
 		}()
 	}
 
 	// create initial jobs
 	if !conf.InMemoryVisitQueue {
-		encoder := json.NewEncoder(visitQueueFile)
 		for _, initialPage := range conf.InitialPages {
 			var newJob web.Job = web.Job{
 				URL:    initialPage,
 				Search: conf.Search,
 				Depth:  conf.Depth,
 			}
-			err = encoder.Encode(&newJob)
+			err = queue.InsertNewJob(visitQueueFile, newJob)
 			if err != nil {
 				logger.Error("Failed to encode an initial job to the visit queue: %s", err)
 				continue

src/queue/visitqueue.go

@@ -0,0 +1,57 @@
+package queue
+
+import (
+	"encoding/json"
+	"io"
+	"os"
+	"unbewohnte/wecr/logger"
+	"unbewohnte/wecr/web"
+)
+
+func PopLastJob(queue *os.File) (*web.Job, error) {
+	stats, err := queue.Stat()
+	if err != nil {
+		return nil, err
+	}
+
+	if stats.Size() == 0 {
+		return nil, nil
+	}
+
+	// find the last job in the queue
+	var job web.Job
+	var offset int64 = -1
+	for {
+		currentOffset, err := queue.Seek(offset, io.SeekEnd)
+		if err != nil {
+			return nil, err
+		}
+
+		decoder := json.NewDecoder(queue)
+		err = decoder.Decode(&job)
+		if err != nil || job.URL == "" || job.Search.Query == "" {
+			offset -= 1
+			continue
+		}
+		logger.Info("Found job: %+v", job)
+
+		queue.Truncate(currentOffset)
+		return &job, nil
+	}
+}
+
+func InsertNewJob(queue *os.File, newJob web.Job) error {
+	offset, err := queue.Seek(0, io.SeekEnd)
+	if err != nil {
+		return err
+	}
+	logger.Info("Inserting at offset %d", offset)
+
+	encoder := json.NewEncoder(queue)
+	err = encoder.Encode(&newJob)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

src/web/job.go

@@ -22,7 +22,7 @@ import "unbewohnte/wecr/config"
 
 // Job to pass around workers
 type Job struct {
-	URL    string
-	Search config.Search
-	Depth  uint
+	URL    string        `json:"u"`
+	Search config.Search `json:"s"`
+	Depth  uint          `json:"d"`
 }

src/worker/worker.go

@@ -25,18 +25,26 @@ import (
 	"path"
 	"path/filepath"
 	"regexp"
+	"sync"
 	"time"
 	"unbewohnte/wecr/config"
 	"unbewohnte/wecr/logger"
+	"unbewohnte/wecr/queue"
 	"unbewohnte/wecr/web"
 )
 
+type VisitQueue struct {
+	VisitQueue *os.File
+	Lock       *sync.Mutex
+}
+
 // Worker configuration
 type WorkerConf struct {
 	Requests           config.Requests
 	Save               config.Save
 	BlacklistedDomains []string
 	AllowedDomains     []string
+	VisitQueue         VisitQueue
 }
 
 // Web worker
@@ -133,7 +141,22 @@ func (w *Worker) Work() {
 		return
 	}
 
-	for job := range w.Jobs {
+	for {
+		var job web.Job
+		if w.Conf.VisitQueue.VisitQueue != nil {
+			w.Conf.VisitQueue.Lock.Lock()
+			newJob, err := queue.PopLastJob(w.Conf.VisitQueue.VisitQueue)
+			if err != nil || newJob == nil {
+				logger.Error("Failed to get a new job from visit queue: %s", err)
+				w.Conf.VisitQueue.Lock.Unlock()
+				continue
+			}
+			job = *newJob
+			w.Conf.VisitQueue.Lock.Unlock()
+		} else {
+			job = <-w.Jobs
+		}
+
 		// check if the worker has been stopped
 		if w.Stopped {
 			// stop working
@@ -209,18 +232,39 @@ func (w *Worker) Work() {
 
 		go func() {
 			if job.Depth > 1 {
-				// decrement depth and add new jobs to the channel
+				// decrement depth and add new jobs
 				job.Depth--
 
-				for _, link := range pageLinks {
-					if link != job.URL {
-						w.Jobs <- web.Job{
-							URL:    link,
-							Search: job.Search,
-							Depth:  job.Depth,
+				if w.Conf.VisitQueue.VisitQueue != nil {
+					// add to the visit queue
+					w.Conf.VisitQueue.Lock.Lock()
+					for _, link := range pageLinks {
+						if link != job.URL {
+							err = queue.InsertNewJob(w.Conf.VisitQueue.VisitQueue, web.Job{
+								URL:    link,
+								Search: job.Search,
+								Depth:  job.Depth,
+							})
+							if err != nil {
+								logger.Error("Failed to encode a new job to a visit queue: %s", err)
+								continue
+							}
+						}
+					}
+					w.Conf.VisitQueue.Lock.Unlock()
+				} else {
+					//  add to the in-memory channel
+					for _, link := range pageLinks {
+						if link != job.URL {
+							w.Jobs <- web.Job{
+								URL:    link,
+								Search: job.Search,
+								Depth:  job.Depth,
+							}
 						}
 					}
 				}
+
 			}
 			pageLinks = nil
 		}()