cmd/swarm: add sliding window tests (v1)

cmd/swarm/swarm-smoke/feed_upload_and_sync.go

@@ -2,13 +2,10 @@ package main
 
 import (
 	"bytes"
-	"context"
 	"crypto/md5"
 	"fmt"
 	"io"
 	"io/ioutil"
-	"net/http"
-	"net/http/httptrace"
 	"os"
 	"os/exec"
 	"strings"
@@ -18,13 +15,8 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
-	"github.com/ethereum/go-ethereum/metrics"
-	"github.com/ethereum/go-ethereum/swarm/api/client"
-	"github.com/ethereum/go-ethereum/swarm/spancontext"
 	"github.com/ethereum/go-ethereum/swarm/storage/feed"
 	"github.com/ethereum/go-ethereum/swarm/testutil"
-	colorable "github.com/mattn/go-colorable"
-	opentracing "github.com/opentracing/opentracing-go"
 	"github.com/pborman/uuid"
 	cli "gopkg.in/urfave/cli.v1"
 )
@@ -33,27 +25,6 @@ const (
 	feedRandomDataLength = 8
 )
 
-func cliFeedUploadAndSync(c *cli.Context) error {
-	metrics.GetOrRegisterCounter("feed-and-sync", nil).Inc(1)
-	log.Root().SetHandler(log.CallerFileHandler(log.LvlFilterHandler(log.Lvl(verbosity), log.StreamHandler(colorable.NewColorableStderr(), log.TerminalFormat(true)))))
-
-	errc := make(chan error)
-	go func() {
-		errc <- feedUploadAndSync(c)
-	}()
-
-	select {
-	case err := <-errc:
-		if err != nil {
-			metrics.GetOrRegisterCounter("feed-and-sync.fail", nil).Inc(1)
-		}
-		return err
-	case <-time.After(time.Duration(timeout) * time.Second):
-		metrics.GetOrRegisterCounter("feed-and-sync.timeout", nil).Inc(1)
-		return fmt.Errorf("timeout after %v sec", timeout)
-	}
-}
-
 // TODO: retrieve with manifest + extract repeating code
 func feedUploadAndSync(c *cli.Context) error {
 	defer func(now time.Time) { log.Info("total time", "time", time.Since(now), "size (kb)", filesize) }(time.Now())
@@ -307,60 +278,3 @@ func feedUploadAndSync(c *cli.Context) error {
 
 	return nil
 }
-
-func fetchFeed(topic string, user string, endpoint string, original []byte, ruid string) error {
-	ctx, sp := spancontext.StartSpan(context.Background(), "feed-and-sync.fetch")
-	defer sp.Finish()
-
-	log.Trace("sleeping", "ruid", ruid)
-	time.Sleep(3 * time.Second)
-
-	log.Trace("http get request (feed)", "ruid", ruid, "api", endpoint, "topic", topic, "user", user)
-
-	var tn time.Time
-	reqUri := endpoint + "/bzz-feed:/?topic=" + topic + "&user=" + user
-	req, _ := http.NewRequest("GET", reqUri, nil)
-
-	opentracing.GlobalTracer().Inject(
-		sp.Context(),
-		opentracing.HTTPHeaders,
-		opentracing.HTTPHeadersCarrier(req.Header))
-
-	trace := client.GetClientTrace("feed-and-sync - http get", "feed-and-sync", ruid, &tn)
-
-	req = req.WithContext(httptrace.WithClientTrace(ctx, trace))
-	transport := http.DefaultTransport
-
-	//transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
-
-	tn = time.Now()
-	res, err := transport.RoundTrip(req)
-	if err != nil {
-		log.Error(err.Error(), "ruid", ruid)
-		return err
-	}
-
-	log.Trace("http get response (feed)", "ruid", ruid, "api", endpoint, "topic", topic, "user", user, "code", res.StatusCode, "len", res.ContentLength)
-
-	if res.StatusCode != 200 {
-		return fmt.Errorf("expected status code %d, got %v (ruid %v)", 200, res.StatusCode, ruid)
-	}
-
-	defer res.Body.Close()
-
-	rdigest, err := digest(res.Body)
-	if err != nil {
-		log.Warn(err.Error(), "ruid", ruid)
-		return err
-	}
-
-	if !bytes.Equal(rdigest, original) {
-		err := fmt.Errorf("downloaded imported file md5=%x is not the same as the generated one=%x", rdigest, original)
-		log.Warn(err.Error(), "ruid", ruid)
-		return err
-	}
-
-	log.Trace("downloaded file matches random file", "ruid", ruid, "len", res.ContentLength)
-
-	return nil
-}

cmd/swarm/swarm-smoke/main.go

@@ -49,6 +49,7 @@ var (
 	verbosity        int
 	timeout          int
 	single           bool
+	storeSize        int
 )
 
 func main() {
@@ -122,6 +123,12 @@ func main() {
 			Usage:       "whether to fetch content from a single node or from all nodes",
 			Destination: &single,
 		},
+		cli.IntFlag{
+			Name:        "store",
+			Value:       5000,
+			Usage:       "individual node store size",
+			Destination: &storeSize,
+		},
 	}
 
 	app.Flags = append(app.Flags, []cli.Flag{
@@ -140,19 +147,25 @@ func main() {
 			Name:    "upload_and_sync",
 			Aliases: []string{"c"},
 			Usage:   "upload and sync",
-			Action:  cliUploadAndSync,
+			Action:  wrapCliCommand("upload-and-sync", uploadAndSync),
 		},
 		{
 			Name:    "feed_sync",
 			Aliases: []string{"f"},
 			Usage:   "feed update generate, upload and sync",
-			Action:  cliFeedUploadAndSync,
+			Action:  wrapCliCommand("feed-and-sync", feedUploadAndSync),
 		},
 		{
 			Name:    "upload_speed",
 			Aliases: []string{"u"},
 			Usage:   "measure upload speed",
-			Action:  cliUploadSpeed,
+			Action:  wrapCliCommand("upload-speed", uploadSpeed),
+		},
+		{
+			Name:    "sliding_window",
+			Aliases: []string{"s"},
+			Usage:   "measure network aggregate capacity",
+			Action:  wrapCliCommand("sliding-window", slidingWindow),
 		},
 	}
 

cmd/swarm/swarm-smoke/sliding_window.go

@@ -0,0 +1,181 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"math/rand"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/swarm/testutil"
+	"github.com/pborman/uuid"
+
+	cli "gopkg.in/urfave/cli.v1"
+)
+
+type uploadResult struct {
+	hash   string
+	digest []byte
+}
+
+func slidingWindow(c *cli.Context) error {
+	// test dscription:
+	// 1. upload repeatedly the same file size, maintain a slice in which swarm hashes are stored, first hash at idx=0
+	// 2. select a random node, start downloading the hashes, starting with the LAST one first (it should always be availble), till the FIRST hash
+	// 3. when
+
+	defer func(now time.Time) {
+		totalTime := time.Since(now)
+
+		log.Info("total time", "time", totalTime)
+		metrics.GetOrRegisterCounter("sliding-window.total-time", nil).Inc(int64(totalTime))
+	}(time.Now())
+
+	generateEndpoints(scheme, cluster, appName, from, to)
+	storeSize = storeSize * 4096 //store size is in chunks - transform to bytes
+	hashes := []uploadResult{}   //swarm hashes of the uploads
+	filesize := storeSize / 7    //each file to upload, bytes
+	nodes := to - from
+	networkCapacity := float64(storeSize) * float64(nodes)
+	const iterationTimeout = 30 * time.Second
+	log.Info("sliding window test started", "store size(kb)", int(storeSize/1000), "nodes", nodes, "filesize(kb)", int(filesize/1000), "network capacity(kb)", int(networkCapacity/1000), "timeout", timeout)
+	uploadedBytes := 0
+	for uploadedBytes = 0; uploadedBytes <= int(networkCapacity); uploadedBytes += filesize {
+		seed := int(time.Now().UnixNano() / 1e6)
+		log.Info("uploading to "+endpoints[0]+" and syncing", "seed", seed)
+
+		randomBytes := testutil.RandomBytes(seed, filesize)
+
+		t1 := time.Now()
+		hash, err := upload(&randomBytes, endpoints[0])
+		if err != nil {
+			log.Error(err.Error())
+			return err
+		}
+		metrics.GetOrRegisterCounter("sliding-window.upload-time", nil).Inc(int64(time.Since(t1)))
+
+		fhash, err := digest(bytes.NewReader(randomBytes))
+		if err != nil {
+			log.Error(err.Error())
+			return err
+		}
+
+		log.Info("uploaded successfully", "hash", hash, "digest", fmt.Sprintf("%x", fhash))
+		hashes = append(hashes, uploadResult{hash: hash, digest: fhash})
+	}
+
+	log.Info("done uploading files", "len(hashes)", len(hashes), "sleep for", syncDelay)
+
+	time.Sleep(time.Duration(syncDelay) * time.Second)
+
+	networkDepth := 0
+	var errored int32 = 0
+
+	timedOut := false
+
+LOOP:
+	for i := len(hashes) - 1; i >= 0; i-- {
+		wg := sync.WaitGroup{}
+		done := time.After(iterationTimeout)
+		if single {
+			rand.Seed(time.Now().UTC().UnixNano())
+			randIndex := 1 + rand.Intn(len(endpoints)-1)
+			ruid := uuid.New()[:8]
+			wg.Add(1)
+			go func(endpoint string, ruid string) {
+				// points to address:
+				// need to measure min/max/mean for the results when not in single mode (not all nodes would necessarily give the same result, though they should)
+				defer wg.Done()
+
+			inner:
+				for {
+					select {
+					case <-done:
+						metrics.GetOrRegisterCounter("sliding-window.single.timeout", nil).Inc(1)
+						atomic.AddInt32(&errored, 1)
+						break inner
+					default:
+					}
+
+					start := time.Now()
+					err := fetch(hashes[i].hash, endpoint, hashes[i].digest, ruid)
+					fetchTime := time.Since(start)
+					if err != nil {
+						continue
+					}
+
+					metrics.GetOrRegisterMeter("sliding-window.single.fetch-time", nil).Mark(int64(fetchTime))
+					return
+				}
+
+			}(endpoints[randIndex], ruid)
+		} else {
+			for _, endpoint := range endpoints {
+				ruid := uuid.New()[:8]
+				wg.Add(1)
+				go func(endpoint string, ruid string) {
+					defer wg.Done()
+
+				inner:
+					for {
+						select {
+						case <-done:
+							metrics.GetOrRegisterCounter("sliding-window.multi.timeout", nil).Inc(1)
+							atomic.AddInt32(&errored, 1)
+							break inner
+						default:
+						}
+
+						start := time.Now()
+						err := fetch(hashes[i].hash, endpoint, hashes[i].digest, ruid)
+						fetchTime := time.Since(start)
+						if err != nil {
+							continue
+						}
+
+						metrics.GetOrRegisterMeter("sliding-window.each.fetch-time", nil).Mark(int64(fetchTime))
+						return
+					}
+				}(endpoint, ruid)
+			}
+		}
+
+		wg.Wait()
+		networkDepth = len(hashes) - i
+		if errored > 0 {
+			break LOOP
+		}
+		select {
+		case <-done:
+			timedOut = true
+			break LOOP
+		default:
+		}
+	}
+
+	log.Info("sliding window test finished", "timed out?", timedOut, "errored?", errored > 0, "networkDepth", networkDepth, "networkDepth(kb)", int(networkDepth*filesize/1000))
+	log.Info("stats", "uploadedFiles", len(hashes), "uploadedKb", uploadedBytes/1000, "filesizeKb", filesize/1000, "networkCapacityKb", int(networkCapacity/1000), "networkCapacityMb", int(networkCapacity/1000000))
+
+	metrics.GetOrRegisterMeter("sliding-window.network-depth", nil).Mark(int64(networkDepth))
+	metrics.GetOrRegisterMeter("sliding-window.uploaded-bytes", nil).Mark(int64(uploadedBytes))
+	return nil
+}

cmd/swarm/swarm-smoke/upload_and_sync.go

@@ -18,75 +18,19 @@ package main
 
 import (
 	"bytes"
-	"context"
-	"crypto/md5"
-	crand "crypto/rand"
-	"errors"
 	"fmt"
-	"io"
-	"io/ioutil"
 	"math/rand"
-	"net/http"
-	"net/http/httptrace"
-	"os"
 	"sync"
 	"time"
 
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/metrics"
-	"github.com/ethereum/go-ethereum/swarm/api"
-	"github.com/ethereum/go-ethereum/swarm/api/client"
-	"github.com/ethereum/go-ethereum/swarm/spancontext"
 	"github.com/ethereum/go-ethereum/swarm/testutil"
-	opentracing "github.com/opentracing/opentracing-go"
 	"github.com/pborman/uuid"
 
 	cli "gopkg.in/urfave/cli.v1"
 )
 
-func generateEndpoints(scheme string, cluster string, app string, from int, to int) {
-	if cluster == "prod" {
-		for port := from; port < to; port++ {
-			endpoints = append(endpoints, fmt.Sprintf("%s://%v.swarm-gateways.net", scheme, port))
-		}
-	} else if cluster == "private-internal" {
-		for port := from; port < to; port++ {
-			endpoints = append(endpoints, fmt.Sprintf("%s://swarm-private-internal-%v:8500", scheme, port))
-		}
-	} else {
-		for port := from; port < to; port++ {
-			endpoints = append(endpoints, fmt.Sprintf("%s://%s-%v-%s.stg.swarm-gateways.net", scheme, app, port, cluster))
-		}
-	}
-
-	if includeLocalhost {
-		endpoints = append(endpoints, "http://localhost:8500")
-	}
-}
-
-func cliUploadAndSync(c *cli.Context) error {
-	log.PrintOrigins(true)
-	log.Root().SetHandler(log.LvlFilterHandler(log.Lvl(verbosity), log.StreamHandler(os.Stdout, log.TerminalFormat(true))))
-
-	metrics.GetOrRegisterCounter("upload-and-sync", nil).Inc(1)
-
-	errc := make(chan error)
-	go func() {
-		errc <- uploadAndSync(c)
-	}()
-
-	select {
-	case err := <-errc:
-		if err != nil {
-			metrics.GetOrRegisterCounter("upload-and-sync.fail", nil).Inc(1)
-		}
-		return err
-	case <-time.After(time.Duration(timeout) * time.Second):
-		metrics.GetOrRegisterCounter("upload-and-sync.timeout", nil).Inc(1)
-		return fmt.Errorf("timeout after %v sec", timeout)
-	}
-}
-
 func uploadAndSync(c *cli.Context) error {
 	defer func(now time.Time) {
 		totalTime := time.Since(now)
@@ -161,96 +105,3 @@ func uploadAndSync(c *cli.Context) error {
 
 	return nil
 }
-
-// fetch is getting the requested `hash` from the `endpoint` and compares it with the `original` file
-func fetch(hash string, endpoint string, original []byte, ruid string) error {
-	ctx, sp := spancontext.StartSpan(context.Background(), "upload-and-sync.fetch")
-	defer sp.Finish()
-
-	log.Trace("http get request", "ruid", ruid, "api", endpoint, "hash", hash)
-
-	var tn time.Time
-	reqUri := endpoint + "/bzz:/" + hash + "/"
-	req, _ := http.NewRequest("GET", reqUri, nil)
-
-	opentracing.GlobalTracer().Inject(
-		sp.Context(),
-		opentracing.HTTPHeaders,
-		opentracing.HTTPHeadersCarrier(req.Header))
-
-	trace := client.GetClientTrace("upload-and-sync - http get", "upload-and-sync", ruid, &tn)
-
-	req = req.WithContext(httptrace.WithClientTrace(ctx, trace))
-	transport := http.DefaultTransport
-
-	//transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
-
-	tn = time.Now()
-	res, err := transport.RoundTrip(req)
-	if err != nil {
-		log.Error(err.Error(), "ruid", ruid)
-		return err
-	}
-	log.Trace("http get response", "ruid", ruid, "api", endpoint, "hash", hash, "code", res.StatusCode, "len", res.ContentLength)
-
-	if res.StatusCode != 200 {
-		err := fmt.Errorf("expected status code %d, got %v", 200, res.StatusCode)
-		log.Warn(err.Error(), "ruid", ruid)
-		return err
-	}
-
-	defer res.Body.Close()
-
-	rdigest, err := digest(res.Body)
-	if err != nil {
-		log.Warn(err.Error(), "ruid", ruid)
-		return err
-	}
-
-	if !bytes.Equal(rdigest, original) {
-		err := fmt.Errorf("downloaded imported file md5=%x is not the same as the generated one=%x", rdigest, original)
-		log.Warn(err.Error(), "ruid", ruid)
-		return err
-	}
-
-	log.Trace("downloaded file matches random file", "ruid", ruid, "len", res.ContentLength)
-
-	return nil
-}
-
-// upload is uploading a file `f` to `endpoint` via the `swarm up` cmd
-func upload(dataBytes *[]byte, endpoint string) (string, error) {
-	swarm := client.NewClient(endpoint)
-	f := &client.File{
-		ReadCloser: ioutil.NopCloser(bytes.NewReader(*dataBytes)),
-		ManifestEntry: api.ManifestEntry{
-			ContentType: "text/plain",
-			Mode:        0660,
-			Size:        int64(len(*dataBytes)),
-		},
-	}
-
-	// upload data to bzz:// and retrieve the content-addressed manifest hash, hex-encoded.
-	return swarm.Upload(f, "", false)
-}
-
-func digest(r io.Reader) ([]byte, error) {
-	h := md5.New()
-	_, err := io.Copy(h, r)
-	if err != nil {
-		return nil, err
-	}
-	return h.Sum(nil), nil
-}
-
-// generates random data in heap buffer
-func generateRandomData(datasize int) ([]byte, error) {
-	b := make([]byte, datasize)
-	c, err := crand.Read(b)
-	if err != nil {
-		return nil, err
-	} else if c != datasize {
-		return nil, errors.New("short read")
-	}
-	return b, nil
-}

cmd/swarm/swarm-smoke/upload_speed.go

@@ -19,7 +19,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"os"
 	"time"
 
 	"github.com/ethereum/go-ethereum/log"
@@ -29,42 +28,6 @@ import (
 	cli "gopkg.in/urfave/cli.v1"
 )
 
-var endpoint string
-
-//just use the first endpoint
-func generateEndpoint(scheme string, cluster string, app string, from int) {
-	if cluster == "prod" {
-		endpoint = fmt.Sprintf("%s://%v.swarm-gateways.net", scheme, from)
-	} else if cluster == "private-internal" {
-		endpoint = fmt.Sprintf("%s://swarm-private-internal-%v:8500", scheme, from)
-	} else {
-		endpoint = fmt.Sprintf("%s://%s-%v-%s.stg.swarm-gateways.net", scheme, app, from, cluster)
-	}
-}
-
-func cliUploadSpeed(c *cli.Context) error {
-	log.PrintOrigins(true)
-	log.Root().SetHandler(log.LvlFilterHandler(log.Lvl(verbosity), log.StreamHandler(os.Stdout, log.TerminalFormat(true))))
-
-	metrics.GetOrRegisterCounter("upload-speed", nil).Inc(1)
-
-	errc := make(chan error)
-	go func() {
-		errc <- uploadSpeed(c)
-	}()
-
-	select {
-	case err := <-errc:
-		if err != nil {
-			metrics.GetOrRegisterCounter("upload-speed.fail", nil).Inc(1)
-		}
-		return err
-	case <-time.After(time.Duration(timeout) * time.Second):
-		metrics.GetOrRegisterCounter("upload-speed.timeout", nil).Inc(1)
-		return fmt.Errorf("timeout after %v sec", timeout)
-	}
-}
-
 func uploadSpeed(c *cli.Context) error {
 	defer func(now time.Time) {
 		totalTime := time.Since(now)
@@ -73,7 +36,7 @@ func uploadSpeed(c *cli.Context) error {
 		metrics.GetOrRegisterCounter("upload-speed.total-time", nil).Inc(int64(totalTime))
 	}(time.Now())
 
-	generateEndpoint(scheme, cluster, appName, from)
+	endpoint := generateEndpoint(scheme, cluster, appName, from)
 	seed := int(time.Now().UnixNano() / 1e6)
 	log.Info("uploading to "+endpoint, "seed", seed)
 

cmd/swarm/swarm-smoke/util.go

@@ -0,0 +1,240 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+
+package main
+
+import (
+	"bytes"
+	"context"
+	"crypto/md5"
+	crand "crypto/rand"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptrace"
+	"os"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/swarm/api"
+	"github.com/ethereum/go-ethereum/swarm/api/client"
+	"github.com/ethereum/go-ethereum/swarm/spancontext"
+	opentracing "github.com/opentracing/opentracing-go"
+	cli "gopkg.in/urfave/cli.v1"
+)
+
+func wrapCliCommand(name string, command func(*cli.Context) error) func(*cli.Context) error {
+	return func(ctx *cli.Context) error {
+		log.PrintOrigins(true)
+		log.Root().SetHandler(log.LvlFilterHandler(log.Lvl(verbosity), log.StreamHandler(os.Stdout, log.TerminalFormat(true))))
+		log.Info("smoke test starting", "task", name, "timeout", timeout)
+		metrics.GetOrRegisterCounter(name, nil).Inc(1)
+
+		errc := make(chan error)
+		go func() {
+			errc <- command(ctx)
+		}()
+
+		select {
+		case err := <-errc:
+			if err != nil {
+				metrics.GetOrRegisterCounter(fmt.Sprintf("%s.fail", name), nil).Inc(1)
+			}
+			return err
+		case <-time.After(time.Duration(timeout) * time.Second):
+			metrics.GetOrRegisterCounter(fmt.Sprintf("%s.timeout", name), nil).Inc(1)
+			return fmt.Errorf("timeout after %v sec", timeout)
+		}
+	}
+}
+
+func generateEndpoints(scheme string, cluster string, app string, from int, to int) {
+	if cluster == "prod" {
+		for port := from; port < to; port++ {
+			endpoints = append(endpoints, fmt.Sprintf("%s://%v.swarm-gateways.net", scheme, port))
+		}
+	} else {
+		for port := from; port < to; port++ {
+			endpoints = append(endpoints, fmt.Sprintf("%s://%s-%v-%s.stg.swarm-gateways.net", scheme, app, port, cluster))
+		}
+	}
+
+	if includeLocalhost {
+		endpoints = append(endpoints, "http://localhost:8500")
+	}
+}
+
+//just use the first endpoint
+func generateEndpoint(scheme string, cluster string, app string, from int) string {
+	if cluster == "prod" {
+		return fmt.Sprintf("%s://%v.swarm-gateways.net", scheme, from)
+	} else {
+		return fmt.Sprintf("%s://%s-%v-%s.stg.swarm-gateways.net", scheme, app, from, cluster)
+	}
+}
+
+func fetchFeed(topic string, user string, endpoint string, original []byte, ruid string) error {
+	ctx, sp := spancontext.StartSpan(context.Background(), "feed-and-sync.fetch")
+	defer sp.Finish()
+
+	log.Trace("sleeping", "ruid", ruid)
+	time.Sleep(3 * time.Second)
+
+	log.Trace("http get request (feed)", "ruid", ruid, "api", endpoint, "topic", topic, "user", user)
+
+	var tn time.Time
+	reqUri := endpoint + "/bzz-feed:/?topic=" + topic + "&user=" + user
+	req, _ := http.NewRequest("GET", reqUri, nil)
+
+	opentracing.GlobalTracer().Inject(
+		sp.Context(),
+		opentracing.HTTPHeaders,
+		opentracing.HTTPHeadersCarrier(req.Header))
+
+	trace := client.GetClientTrace("feed-and-sync - http get", "feed-and-sync", ruid, &tn)
+
+	req = req.WithContext(httptrace.WithClientTrace(ctx, trace))
+	transport := http.DefaultTransport
+
+	//transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
+
+	tn = time.Now()
+	res, err := transport.RoundTrip(req)
+	if err != nil {
+		log.Error(err.Error(), "ruid", ruid)
+		return err
+	}
+
+	log.Trace("http get response (feed)", "ruid", ruid, "api", endpoint, "topic", topic, "user", user, "code", res.StatusCode, "len", res.ContentLength)
+
+	if res.StatusCode != 200 {
+		return fmt.Errorf("expected status code %d, got %v (ruid %v)", 200, res.StatusCode, ruid)
+	}
+
+	defer res.Body.Close()
+
+	rdigest, err := digest(res.Body)
+	if err != nil {
+		log.Warn(err.Error(), "ruid", ruid)
+		return err
+	}
+
+	if !bytes.Equal(rdigest, original) {
+		err := fmt.Errorf("downloaded imported file md5=%x is not the same as the generated one=%x", rdigest, original)
+		log.Warn(err.Error(), "ruid", ruid)
+		return err
+	}
+
+	log.Trace("downloaded file matches random file", "ruid", ruid, "len", res.ContentLength)
+
+	return nil
+}
+
+// fetch is getting the requested `hash` from the `endpoint` and compares it with the `original` file
+func fetch(hash string, endpoint string, original []byte, ruid string) error {
+	ctx, sp := spancontext.StartSpan(context.Background(), "upload-and-sync.fetch")
+	defer sp.Finish()
+
+	log.Trace("http get request", "ruid", ruid, "api", endpoint, "hash", hash)
+
+	var tn time.Time
+	reqUri := endpoint + "/bzz:/" + hash + "/"
+	req, _ := http.NewRequest("GET", reqUri, nil)
+
+	opentracing.GlobalTracer().Inject(
+		sp.Context(),
+		opentracing.HTTPHeaders,
+		opentracing.HTTPHeadersCarrier(req.Header))
+
+	trace := client.GetClientTrace("upload-and-sync - http get", "upload-and-sync", ruid, &tn)
+
+	req = req.WithContext(httptrace.WithClientTrace(ctx, trace))
+	transport := http.DefaultTransport
+
+	//transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
+
+	tn = time.Now()
+	res, err := transport.RoundTrip(req)
+	if err != nil {
+		log.Error(err.Error(), "ruid", ruid)
+		return err
+	}
+	log.Trace("http get response", "ruid", ruid, "api", endpoint, "hash", hash, "code", res.StatusCode, "len", res.ContentLength)
+
+	if res.StatusCode != 200 {
+		err := fmt.Errorf("expected status code %d, got %v", 200, res.StatusCode)
+		log.Warn(err.Error(), "ruid", ruid)
+		return err
+	}
+
+	defer res.Body.Close()
+
+	rdigest, err := digest(res.Body)
+	if err != nil {
+		log.Warn(err.Error(), "ruid", ruid)
+		return err
+	}
+
+	if !bytes.Equal(rdigest, original) {
+		err := fmt.Errorf("downloaded imported file md5=%x is not the same as the generated one=%x", rdigest, original)
+		log.Warn(err.Error(), "ruid", ruid)
+		return err
+	}
+
+	log.Trace("downloaded file matches random file", "ruid", ruid, "len", res.ContentLength)
+
+	return nil
+}
+
+// upload an arbitrary byte as a plaintext file  to `endpoint` using the api client
+func upload(dataBytes *[]byte, endpoint string) (string, error) {
+	swarm := client.NewClient(endpoint)
+	f := &client.File{
+		ReadCloser: ioutil.NopCloser(bytes.NewReader(*dataBytes)),
+		ManifestEntry: api.ManifestEntry{
+			ContentType: "text/plain",
+			Mode:        0660,
+			Size:        int64(len(*dataBytes)),
+		},
+	}
+
+	// upload data to bzz:// and retrieve the content-addressed manifest hash, hex-encoded.
+	return swarm.Upload(f, "", false)
+}
+
+func digest(r io.Reader) ([]byte, error) {
+	h := md5.New()
+	_, err := io.Copy(h, r)
+	if err != nil {
+		return nil, err
+	}
+	return h.Sum(nil), nil
+}
+
+// generates random data in heap buffer
+func generateRandomData(datasize int) ([]byte, error) {
+	b := make([]byte, datasize)
+	c, err := crand.Read(b)
+	if err != nil {
+		return nil, err
+	} else if c != datasize {
+		return nil, errors.New("short read")
+	}
+	return b, nil
+}