fixed on image cache

Signed-off-by: p4u <[email protected]>

image.go

@@ -56,6 +56,7 @@ func (v *vocdoniHandler) imagesHandler(msg *apirest.APIdata, ctx *httprouter.HTT
 	// check if the election is finished and if so, send the final results as a static PNG
 	pngResults := v.db.FinalResultsPNG(electionID)
 	if pngResults != nil {
+		log.Warnw("image recovery, found final results PNG!", "electionID", electionID, "imgID", id)
 		// for future requests, add the image to the cache with the given id
 		imageframe.AddImageToCacheWithID(id, pngResults)
 		return imageResponse(ctx, pngResults)
@@ -70,8 +71,7 @@ func (v *vocdoniHandler) imagesHandler(msg *apirest.APIdata, ctx *httprouter.HTT
 	if err != nil {
 		return errorImageResponse(ctx, fmt.Errorf("failed to build landing: %w", err))
 	}
-	// for future requests, add the image to the cache with the given id
-	imageframe.AddImageToCacheWithID(id, imageframe.FromCache(png))
+	log.Warnw("image recovery, built landing PNG", "electionID", electionID, "imgID", id)
 	return imageResponse(ctx, imageframe.FromCache(png))
 }
 

imageframe/cache.go

@@ -6,35 +6,45 @@ import (
 
 	"github.com/zeebo/blake3"
 	"go.vocdoni.io/dvote/api"
+	"go.vocdoni.io/dvote/log"
 )
 
-// cacheElectionID returns a unique identifier cache key, for the election.
+// generateElectionCacheKey returns a unique identifier cache key, for the election.
 // The cache key is based on the electionID, voteCount and finalResults.
-func cacheElectionID(election *api.Election) string {
+func generateElectionCacheKey(election *api.Election, imageType int) string {
 	if election == nil {
 		return ""
 	}
-	return fmt.Sprintf("%s_%d-%d", election.ElectionID.String(), election.VoteCount, func() int {
-		if election.FinalResults {
-			return 1
-		}
-		return 0
-	}())
+	switch imageType {
+	case imageTypeResults:
+		return fmt.Sprintf("%s_%d-%d%d", election.ElectionID.String(), election.VoteCount, func() int {
+			if election.FinalResults {
+				return 1
+			}
+			return 0
+		}(), imageType)
+	case imageTypeQuestion:
+		return fmt.Sprintf("%s_%d", election.ElectionID.String(), imageType)
+	default:
+		log.Errorw(fmt.Errorf("unknown image type %d", imageType), "cacheElectionID")
+		// fallback
+		return fmt.Sprintf("%s_%d", election.ElectionID.String(), imageType)
+	}
 }
 
-// addElectionImageToCache adds an image to the LRU cache.
+// cacheElectionImage adds an image to the LRU cache.
 // Returns the cache key.
 // If electionID is nil, the image is not associated with any election.
-func addElectionImageToCache(data []byte, election *api.Election) string {
-	id := cacheElectionID(election)
+func cacheElectionImage(data []byte, election *api.Election, imageType int) string {
+	id := generateElectionCacheKey(election, imageType)
 	imagesLRU.Add(id, data)
 	return id
 }
 
-// electionImageInCache checks if an election associated image exist in the LRU cache.
+// electionImageCacheKey checks if an election associated image exist in the LRU cache.
 // If so it returns the cache key identifier, otherwise it returns an empty string.
-func electionImageInCache(election *api.Election) string {
-	id := cacheElectionID(election)
+func electionImageCacheKey(election *api.Election, imageType int) string {
+	id := generateElectionCacheKey(election, imageType)
 	_, ok := imagesLRU.Get(id)
 	if !ok {
 		missesCounter.Add(1)
@@ -68,7 +78,7 @@ func FromCache(id string) []byte {
 	// Retry for a maximyum time of 8 seconds if the image is not in the cache
 	startTime := time.Now()
 	for {
-		if time.Since(startTime) > 8*time.Second {
+		if time.Since(startTime) > TimeoutImageGeneration {
 			return nil
 		}
 		data, ok := imagesLRU.Get(id)

imageframe/imageframe.go

@@ -24,6 +24,14 @@ const (
 
 	BackgroundsDir    = "images/"
 	ImageGeneratorURL = "https://img.frame.vote"
+
+	TimeoutImageGeneration = 20 * time.Second
+)
+
+const (
+	imageType = iota
+	imageTypeQuestion
+	imageTypeResults
 )
 
 var backgroundFrames map[string][]byte
@@ -108,7 +116,7 @@ func QuestionImage(election *api.Election) (string, error) {
 		return "", fmt.Errorf("election has no questions")
 	}
 	// Check if the image is already in the cache
-	if id := electionImageInCache(election); id != "" {
+	if id := electionImageCacheKey(election, imageTypeQuestion); id != "" {
 		return id, nil
 	}
 
@@ -129,9 +137,9 @@ func QuestionImage(election *api.Election) (string, error) {
 			log.Warnw("failed to create image", "error", err)
 			return
 		}
-		addElectionImageToCache(png, election)
+		cacheElectionImage(png, election, imageTypeQuestion)
 	}()
-	return cacheElectionID(election), nil
+	return generateElectionCacheKey(election, imageTypeQuestion), nil
 }
 
 // ResultsImage creates an image showing the results of a poll.
@@ -140,7 +148,7 @@ func ResultsImage(election *api.Election) (string, error) {
 		return "", fmt.Errorf("election has no questions")
 	}
 	// Check if the image is already in the cache
-	if id := electionImageInCache(election); id != "" {
+	if id := electionImageCacheKey(election, imageTypeResults); id != "" {
 		return id, nil
 	}
 
@@ -167,9 +175,9 @@ func ResultsImage(election *api.Election) (string, error) {
 			log.Warnw("failed to create image", "error", err)
 			return
 		}
-		addElectionImageToCache(png, election)
+		cacheElectionImage(png, election, imageTypeResults)
 	}()
-	return cacheElectionID(election), nil
+	return generateElectionCacheKey(election, imageTypeResults), nil
 }
 
 // AfterVoteImage creates a static image to be displayed after a vote has been cast.

mongo/results.go

@@ -2,25 +2,33 @@ package mongo
 
 import (
 	"context"
+	"fmt"
 	"time"
 
 	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo/options"
 	"go.vocdoni.io/dvote/log"
 	"go.vocdoni.io/dvote/types"
 )
 
 // AddFinalResults adds the final results of an election in PNG format.
+// It performs and upsert operation, so it will update the results if they already exist.
 func (ms *MongoStorage) AddFinalResults(electionID types.HexBytes, finalPNG []byte) error {
 	results := &Results{
 		ElectionID: electionID.String(),
 		FinalPNG:   finalPNG,
 	}
-
-	ctx2, cancel2 := context.WithTimeout(context.Background(), 5*time.Second)
-	defer cancel2()
-	_, err := ms.results.InsertOne(ctx2, results)
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	opts := options.ReplaceOptions{}
+	opts.Upsert = new(bool)
+	*opts.Upsert = true
+	_, err := ms.results.ReplaceOne(ctx, bson.M{"_id": results.ElectionID}, results, &opts)
+	if err != nil {
+		return fmt.Errorf("cannot update object: %w", err)
+	}
 	log.Debugw("stored PNG results", "electionID", electionID.String())
-	return err
+	return nil
 }
 
 // FinalResultsPNG returns the final results of an election in PNG format.

results.go

@@ -67,14 +67,22 @@ func (v *vocdoniHandler) results(msg *apirest.APIdata, ctx *httprouter.HTTPConte
 		if err != nil {
 			return fmt.Errorf("failed to create image: %w", err)
 		}
-		if err := v.db.AddFinalResults(electionIDbytes, imageframe.FromCache(id)); err != nil {
-			return fmt.Errorf("failed to add final results to database: %w", err)
-		}
-		log.Infow("final results image built ondemand", "electionID", electionID)
-		if v.checkIfElectionFinishedAndHandle(electionIDbytes, ctx) {
-			return nil
-		}
+		go func() {
+			if err := v.db.AddFinalResults(electionIDbytes, imageframe.FromCache(id)); err != nil {
+				log.Errorw(err, "failed to add final results to database")
+				return
+			}
+			log.Infow("final results image built ondemand", "electionID", electionID)
+		}()
+
+		response := strings.ReplaceAll(frame(frameFinalResults), "{image}", imageLink(id))
+		response = strings.ReplaceAll(response, "{processID}", electionID)
+		response = strings.ReplaceAll(response, "{title}", "Final results")
+
+		ctx.SetResponseContentType("text/html; charset=utf-8")
+		return ctx.Send([]byte(response), http.StatusOK)
 	}
+
 	// if not final results, create the dynamic PNG image with the results
 	response := strings.ReplaceAll(frame(frameResults), "{image}", resultsPNGfile(election))
 	response = strings.ReplaceAll(response, "{title}", election.Metadata.Title["default"])