Optimize memory usage by avoiding accumulating all the referred

documents into a single stack.

api/internal/crawl/cmd/crawler/crawler.go

@@ -159,40 +159,31 @@ func main() {
 		}
 	}
 
-	seedDocs := make(crawler.CrawlSeed, 0)
-
-	// get all the documents in the index
-	getSeedDocsFunc := func() {
 	query := []byte(`{ "query":{ "match_all":{} } }`)
 	it := idx.IterateQuery(query, 10000, 60*time.Second)
-		for it.Next() {
-			for _, hit := range it.Value().Hits.Hits {
-				seedDocs = append(seedDocs, hit.Document.Document.Copy())
-			}
-		}
-		if err := it.Err(); err != nil {
-			log.Fatalf("getSeedDocsFunc Error iterating: %v\n", err)
-		}
-	}
 
 	switch mode {
 	case CrawlIndexAndGithub:
-		getSeedDocsFunc()
 		crawlers := []crawler.Crawler{ghCrawlerConstructor("", "")}
-		crawler.CrawlFromSeed(ctx, seedDocs, crawlers, docConverter, indexFunc, seen)
+		crawler.CrawlFromSeedIterator(ctx, it, crawlers, docConverter, indexFunc, seen)
 		crawler.CrawlGithub(ctx, crawlers, docConverter, indexFunc, seen)
 	case CrawlIndex:
-		getSeedDocsFunc()
 		crawlers := []crawler.Crawler{ghCrawlerConstructor("", "")}
-		crawler.CrawlFromSeed(ctx, seedDocs, crawlers, docConverter, indexFunc, seen)
+		crawler.CrawlFromSeedIterator(ctx, it, crawlers, docConverter, indexFunc, seen)
 	case CrawlGithub:
 		crawlers := []crawler.Crawler{ghCrawlerConstructor("", "")}
 		// add all the documents in the index into seen.
 		// this greatly reduces the time overhead of CrawlGithub.
-		getSeedDocsFunc()
-		for _, d := range seedDocs {
+		for it.Next() {
+			for _, hit := range it.Value().Hits.Hits {
+				d := hit.Document.Document
 				seen.Set(d.ID(), d.FileType)
 			}
+		}
+		if err := it.Err(); err != nil {
+			log.Fatalf("Error iterating the index: %v\n", err)
+		}
+
 		crawler.CrawlGithub(ctx, crawlers, docConverter, indexFunc, seen)
 	case CrawlUser:
 		if *githubUserPtr == "" {

api/internal/crawl/crawler/crawler.go

@@ -213,21 +213,36 @@ func doCrawl(ctx context.Context, docsPtr *CrawlSeed, crawlers []Crawler, conv C
 	logger.Printf("\t%d documents cannot be converted but still were inserted or updated in the index\n", convErrCount)
 }
 
+// CrawlFromSeedIterator iterates all the documents in the index and call CrawlFromSeed for each document.
+func CrawlFromSeedIterator(ctx context.Context, it *index.KustomizeIterator, crawlers []Crawler,
+	conv Converter, indx IndexFunc, seen utils.SeenMap) {
+	docCount := 0
+	for it.Next() {
+		for _, hit := range it.Value().Hits.Hits {
+			docCount++
+			logger.Printf("updating document %d from seed\n", docCount)
+
+			singleSeed := CrawlSeed{&(hit.Document.Document)}
+			CrawlFromSeed(ctx, singleSeed, crawlers, conv, indx, seen)
+		}
+	}
+	if err := it.Err(); err != nil {
+		log.Fatalf("Error iterating the index: %v\n", err)
+	}
+}
+
 // CrawlFromSeed updates all the documents in seed, and crawls all the new
 // documents referred in the seed.
 func CrawlFromSeed(ctx context.Context, seed CrawlSeed, crawlers []Crawler,
 	conv Converter, indx IndexFunc, seen utils.SeenMap) {
 
-	// stack tracks the documents directly referred in other documents.
+	// stack tracks the documents directly referred in the seed.
 	stack := make(CrawlSeed, 0)
 
-	// Exploit seed to update bulk of corpus.
-	logger.Printf("updating %d documents from seed\n", len(seed))
 	// each unique document in seed will be crawled once.
 	doCrawl(ctx, &seed, crawlers, conv, indx, seen, &stack, true, false)
 
-	// Traverse any new documents added while updating corpus.
-	logger.Printf("crawling %d new documents found in the seed\n", len(stack))
+	logger.Printf("crawling %d new documents referred by doc\n", len(stack))
 	// While crawling each document in stack, the documents directly referred in the document
 	// will be added into stack.
 	// After this statement is done, stack will become empty.
@@ -297,8 +312,6 @@ func CrawlGithubRunner(ctx context.Context, output chan<- CrawledDocument,
 // CrawlGithub crawls all the kustomization files on Github.
 func CrawlGithub(ctx context.Context, crawlers []Crawler, conv Converter,
 	indx IndexFunc, seen utils.SeenMap) {
-	// stack tracks the documents directly referred in other documents.
-	stack := make(CrawlSeed, 0)
 
 	// ch is channel where all the crawlers sends the crawled documents to.
 	ch := make(chan CrawledDocument, 1<<10)
@@ -324,7 +337,20 @@ func CrawlGithub(ctx context.Context, crawlers []Crawler, conv Converter,
 					"%v could not match any crawler", cdoc))
 				continue
 			}
+
+			// stack tracks the documents directly referred in the document.
+			stack := make(CrawlSeed, 0)
+
 			addBranches(cdoc, match, indx, seen, &stack)
+
+			if len(stack) > 0 {
+				// here the documents referred in a kustomization file are crawled separately,
+				// to avoid accumulating all the referred documents into a single gigantic
+				// mem-inentive stack.
+				logger.Printf("crawling the %d new documents referred in doc %d",
+					len(stack), docCount)
+				doCrawl(ctx, &stack, crawlers, conv, indx, seen, &stack, false, true)
+			}
 		}
 	}()
 
@@ -336,9 +362,4 @@ func CrawlGithub(ctx context.Context, crawlers []Crawler, conv Converter,
 	}
 	close(ch)
 	wg.Wait()
-
-	// Handle deps of newly discovered documents.
-	logger.Printf("crawling the %d new documents referred by other documents",
-		len(stack))
-	doCrawl(ctx, &stack, crawlers, conv, indx, seen, &stack, false, true)
 }