adds stats page

close #6

backend/app.go

@@ -1,31 +1,59 @@
 package backend
 
 import (
+	"encoding/json"
 	"net/http"
 	"time"
 
 	"google.golang.org/appengine"
+	"google.golang.org/appengine/log"
 )
 
 func init() {
 	http.HandleFunc("/poll", pollFunc)
+	http.HandleFunc("/update-stats", updateStatsFunc)
 	http.HandleFunc("/stats", statsFunc)
 }
 
 func statsFunc(w http.ResponseWriter, r *http.Request) {
 	ctx := appengine.NewContext(r)
 
+	db := &Datastore{ctx}
+	logger := &AELogger{ctx}
+
+	be := &Backend{db, nil, logger, nil}
+
+	s, err := be.latestStats()
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return
+	}
+
+	b, err := json.Marshal(s)
+	if err != nil {
+		log.Errorf(ctx, "cannot marshal %v", s)
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return
+	}
+	w.Write(b)
+}
+
+func updateStatsFunc(w http.ResponseWriter, r *http.Request) {
+	ctx := appengine.NewContext(r)
+
 	db := &Datastore{ctx}
 	provider := &Blockcypher{ctx}
 	logger := &AELogger{ctx}
 	reactor := &AEReactor{ctx}
 
 	b := &Backend{db, provider, logger, reactor}
 
-	err := b.stats(time.Now())
+	err := b.updateStats(time.Now())
 	if err != nil {
 		w.WriteHeader(http.StatusInternalServerError)
-		w.Write([]byte("err " + err.Error()))
+		w.Write([]byte(err.Error()))
 	}
 }
 

backend/app.yaml

@@ -10,7 +10,7 @@ handlers:
   secure: always
   login: admin
 
-- url: /stats
+- url: /update-stats
   script: _go_app
   secure: always
   login: admin

backend/backend.go

@@ -51,7 +51,11 @@ type Backend struct {
 
 var day = time.Hour * 24
 
-func (be *Backend) stats(ts time.Time) error {
+func (be *Backend) latestStats() (Stats, error) {
+	return be.LatestStats()
+}
+
+func (be *Backend) updateStats(ts time.Time) error {
 	s := Stats{Timestamp: ts, Votes: make(map[string]Vote)}
 
 	d30ts := ts.Add(-day * 30)
@@ -122,7 +126,7 @@ func makeVote(cs []int, total []int) Vote {
 func (be *Backend) poll() error {
 	// determine next block height
 	var h int
-	lb, err := be.Latest()
+	lb, err := be.LatestBlock()
 	switch err {
 	case ErrNoBlocks:
 		// height from config

backend/backend_test.go

@@ -14,10 +14,14 @@ func (db *TestDB) GetConfig() (Config, error) {
 	return Config{}, nil
 }
 
-func (db *TestDB) Latest() (Block, error) {
+func (db *TestDB) LatestBlock() (Block, error) {
 	return Block{}, nil
 }
 
+func (db *TestDB) LatestStats() (Stats, error) {
+	return Stats{}, nil
+}
+
 func (db *TestDB) SaveBlock(Block) error {
 	return nil
 }
@@ -89,7 +93,7 @@ func Test_Stats(t *testing.T) {
 	db := &TestDB{blocks: []Block{b1, b2, b3, b4}}
 
 	be := &Backend{db, nil, &TestLogger{}, &TestReactor{}}
-	err := be.stats(ts)
+	err := be.updateStats(ts)
 	if err != nil {
 		t.Fatalf("stats failed: %v", err)
 	}

backend/db.go

@@ -12,6 +12,7 @@ import (
 // Errors
 var (
 	ErrNoBlocks = errors.New("no blocks available")
+	ErrNoStats  = errors.New("no stats available")
 )
 
 // Datastore implements DB via Google Cloud Datastore
@@ -27,8 +28,11 @@ type DB interface {
 	// GetConfig gets the current config from the database
 	GetConfig() (Config, error)
 
-	// Latest returns the latest block (by height) in the database
-	Latest() (Block, error)
+	// LatestBlock returns the latest block (by height) in the database
+	LatestBlock() (Block, error)
+
+	// LatestStats returns the latest stats in the database
+	LatestStats() (Stats, error)
 
 	// SaveStats saves the given stats into the db
 	SaveStats(Stats) error
@@ -85,8 +89,8 @@ func (ds *Datastore) GetConfig() (c Config, err error) {
 	return c, err
 }
 
-// Latest returns the latest block (by height) in the database
-func (ds *Datastore) Latest() (b Block, err error) {
+// LatestBlock returns the latest block (by height) in the database
+func (ds *Datastore) LatestBlock() (b Block, err error) {
 	// run query
 	bs := []Block{}
 	_, err = datastore.NewQuery("Block").
@@ -106,6 +110,41 @@ func (ds *Datastore) Latest() (b Block, err error) {
 	return
 }
 
+// LatestStats returns the latest stats in the database
+func (ds *Datastore) LatestStats() (Stats, error) {
+	ss := []Stats{}
+
+	ks, err := datastore.NewQuery("Stats").
+		Limit(1).
+		Order("-Timestamp").
+		GetAll(ds.ctx, &ss)
+	if err != nil {
+		return Stats{}, err
+	}
+
+	if len(ss) == 0 {
+		return Stats{}, ErrNoStats
+	}
+
+	s := ss[0]
+	k := ks[0]
+
+	var vs []Vote
+	vks, err := datastore.NewQuery("Vote").
+		Ancestor(k).
+		GetAll(ds.ctx, &vs)
+	if err != nil {
+		return Stats{}, err
+	}
+
+	s.Votes = make(map[string]Vote)
+	for i, v := range vs {
+		s.Votes[vks[i].StringID()] = v
+	}
+
+	return s, nil
+}
+
 // ForEachFrom calls the given method for each saves Block starting from the
 // given Timestamp
 func (ds *Datastore) ForEachFrom(ts time.Time, f func(Block)) error {

backend/db_test.go

@@ -86,7 +86,7 @@ func Test_Latest_OK(t *testing.T) {
 	db.SaveBlock(b1)
 	db.SaveBlock(b2)
 
-	b, err := db.Latest()
+	b, err := db.LatestBlock()
 
 	if err != nil {
 		t.Fatal(err)
@@ -107,7 +107,7 @@ func Test_Latest_ErrNoBlocks(t *testing.T) {
 
 	db := Datastore{ctx}
 
-	_, err := db.Latest()
+	_, err := db.LatestBlock()
 
 	if err != ErrNoBlocks {
 		t.Fatal("should have no blocks error")

backend/reactor.go

@@ -18,7 +18,7 @@ type AEReactor struct {
 
 // TriggerUpdateStats triggers a stats update
 func (r *AEReactor) TriggerUpdateStats() error {
-	t := taskqueue.NewPOSTTask("/stats", nil)
+	t := taskqueue.NewPOSTTask("/update-stats", nil)
 	_, err := taskqueue.Add(r.ctx, t, "")
 	return err
 }