add mongodb implementation for the db package

The db interface has now an implementation for mongodb. So instead
of pebble a user or consumer of the vocdoni-node API can choose
to use mongodb. Its not faster than local KV, but useful when the host
runing the database has no persistent storage available, so a remote
storage is required.

The mongodb url must be set on a env var, such as:

MONGODB_URL="mongodb://root:vocdoni@localhost:27017/" go run ./cmd/node -t mongodb -c dev

api/api.go

@@ -15,6 +15,7 @@ import (
 	"go.vocdoni.io/dvote/data"
 	"go.vocdoni.io/dvote/db"
 	"go.vocdoni.io/dvote/db/metadb"
+	"go.vocdoni.io/dvote/db/prefixeddb"
 	"go.vocdoni.io/dvote/httprouter"
 	"go.vocdoni.io/dvote/httprouter/apirest"
 	"go.vocdoni.io/dvote/vochain"
@@ -75,10 +76,13 @@ type API struct {
 }
 
 // NewAPI creates a new instance of the API.  Attach must be called next.
-func NewAPI(router *httprouter.HTTProuter, baseRoute, dataDir string) (*API, error) {
+func NewAPI(router *httprouter.HTTProuter, baseRoute, dataDir, dbType string) (*API, error) {
 	if router == nil {
 		return nil, ErrHTTPRouterIsNil
 	}
+	if dbType == "" {
+		dbType = db.TypePebble
+	}
 	if len(baseRoute) == 0 || baseRoute[0] != '/' {
 		return nil, fmt.Errorf("%w (invalid given: %s)", ErrBaseRouteInvalid, baseRoute)
 	}
@@ -95,10 +99,11 @@ func NewAPI(router *httprouter.HTTProuter, baseRoute, dataDir string) (*API, err
 	if err != nil {
 		return nil, err
 	}
-	api.db, err = metadb.New(db.TypePebble, filepath.Join(dataDir, "db"))
+	mdb, err := metadb.New(dbType, filepath.Join(dataDir, "db"))
 	if err != nil {
 		return nil, err
 	}
+	api.db = prefixeddb.NewPrefixedDatabase(mdb, []byte("api/"))
 	return &api, nil
 }
 

api/census_test.go

@@ -32,7 +32,7 @@ func TestCensus(t *testing.T) {
 	addr, err := url.Parse("http://" + path.Join(router.Address().String(), "censuses"))
 	qt.Assert(t, err, qt.IsNil)
 
-	api, err := NewAPI(&router, "/", t.TempDir())
+	api, err := NewAPI(&router, "/", t.TempDir(), db.TypePebble)
 	qt.Assert(t, err, qt.IsNil)
 
 	// Create local key value database
@@ -162,7 +162,7 @@ func TestCensusProof(t *testing.T) {
 	addr, err := url.Parse("http://" + path.Join(router.Address().String(), "censuses"))
 	qt.Assert(t, err, qt.IsNil)
 
-	api, err := NewAPI(&router, "/", t.TempDir())
+	api, err := NewAPI(&router, "/", t.TempDir(), db.TypePebble)
 	qt.Assert(t, err, qt.IsNil)
 	// Create local key value database
 	db, err := metadb.New(db.TypePebble, t.TempDir())
@@ -248,7 +248,7 @@ func TestCensusZk(t *testing.T) {
 	addr, err := url.Parse("http://" + path.Join(router.Address().String(), "censuses"))
 	c.Assert(err, qt.IsNil)
 
-	testApi, err := NewAPI(&router, "/", t.TempDir())
+	testApi, err := NewAPI(&router, "/", t.TempDir(), db.TypePebble)
 	c.Assert(err, qt.IsNil)
 
 	// Create local key value database

benchmark/zk_census_benchmark_test.go

@@ -35,7 +35,7 @@ func BenchmarkZkCensus(b *testing.B) {
 	router := httprouter.HTTProuter{}
 	router.Init("127.0.0.1", 0)
 
-	vocApi, err := api.NewAPI(&router, "/", b.TempDir())
+	vocApi, err := api.NewAPI(&router, "/", b.TempDir(), db.TypePebble)
 	qt.Assert(b, err, qt.IsNil)
 
 	// Create local key value database

cmd/node/main.go

@@ -75,7 +75,7 @@ func newConfig() (*config.Config, config.Error) {
 	flag.StringVarP(&globalCfg.DataDir, "dataDir", "d", home+"/.vocdoni",
 		"directory where data is stored")
 	flag.StringVarP(&globalCfg.Vochain.DBType, "dbType", "t", db.TypePebble,
-		fmt.Sprintf("key-value db type (%s)", db.TypePebble))
+		fmt.Sprintf("key-value db type [%s,%s,%s]", db.TypePebble, db.TypeLevelDB, db.TypeMongo))
 	flag.StringVarP(&globalCfg.Vochain.Chain, "chain", "c", "dev",
 		fmt.Sprintf("vocdoni blockchain to connect with: %q", genesis.AvailableChains()))
 	flag.BoolVar(&globalCfg.Dev, "dev", false,
@@ -361,10 +361,6 @@ func main() {
 	if !globalCfg.ValidMode() {
 		log.Fatalf("mode %s is invalid", globalCfg.Mode)
 	}
-	// Check the dbType is valid
-	if !globalCfg.Vochain.ValidDBType() {
-		log.Fatalf("dbType %s is invalid. Valid ones: %s", globalCfg.Vochain.DBType, db.TypePebble)
-	}
 
 	// If dev enabled, expose debugging profiles under an http server
 	// If PprofPort is not set, a random port between 61000 and 61100 is choosed.
@@ -531,7 +527,7 @@ func main() {
 		// HTTP API REST service
 		if globalCfg.EnableAPI {
 			log.Info("enabling API")
-			uAPI, err := urlapi.NewAPI(srv.Router, "/v2", globalCfg.DataDir)
+			uAPI, err := urlapi.NewAPI(srv.Router, "/v2", globalCfg.DataDir, globalCfg.Vochain.DBType)
 			if err != nil {
 				log.Fatal(err)
 			}

config/config.go

@@ -1,7 +1,6 @@
 package config
 
 import (
-	"go.vocdoni.io/dvote/db"
 	"go.vocdoni.io/dvote/types"
 )
 
@@ -61,17 +60,6 @@ func (c *Config) ValidMode() bool {
 	return true
 }
 
-// ValidDBType checks if the configured dbType is valid
-func (c *VochainCfg) ValidDBType() bool {
-	switch c.DBType {
-	case db.TypePebble:
-
-	default:
-		return false
-	}
-	return true
-}
-
 // NewConfig initializes the fields in the config stuct.
 func NewConfig() *Config {
 	return &Config{

db/interface.go

@@ -9,6 +9,7 @@ import (
 const (
 	TypePebble  = "pebble"
 	TypeLevelDB = "leveldb"
+	TypeMongo   = "mongodb"
 )
 
 // ErrKeyNotFound is used to indicate that a key does not exist in the db.

db/internal/dbtest/dbtest.go

@@ -32,6 +32,8 @@ func TestWriteTx(t *testing.T, database db.Database) {
 	// Discard should not give any problem
 	wTx.Discard()
 
+	qt.Assert(t, err, qt.IsNil)
+
 	// get value from a new db after the previous commit
 	wTx = database.WriteTx()
 	v, err = wTx.Get([]byte("a"))

db/metadb/metadb.go

@@ -7,6 +7,7 @@ import (
 
 	"go.vocdoni.io/dvote/db"
 	"go.vocdoni.io/dvote/db/goleveldb"
+	"go.vocdoni.io/dvote/db/mongodb"
 	"go.vocdoni.io/dvote/db/pebbledb"
 )
 
@@ -25,8 +26,14 @@ func New(typ, dir string) (db.Database, error) {
 		if err != nil {
 			return nil, err
 		}
+	case db.TypeMongo:
+		database, err = mongodb.New(opts)
+		if err != nil {
+			return nil, err
+		}
 	default:
-		return nil, fmt.Errorf("invalid dbType: %q. Available types: %q", typ, db.TypePebble)
+		return nil, fmt.Errorf("invalid dbType: %q. Available types: %q %q %q",
+			typ, db.TypePebble, db.TypeLevelDB, db.TypeMongo)
 	}
 	return database, nil
 }

db/mongodb/docker-compose-mongo.yml

@@ -0,0 +1,22 @@
+# Use root/example as user/password credentials
+version: '3.1'
+
+services:
+
+  mongo:
+    image: 'bitnami/mongodb:latest'
+    restart: ${RESTART:-no}
+    ports:
+      - 27017:27017
+    environment:
+      - MONGODB_USERNAME=root
+      - MONGODB_PASSWORD=vocdoni
+      - MONGODB_DATABASE=oauth
+      - MONGODB_ROOT_PASSWORD=vocdoni
+    volumes:
+      - mongodb:/bitnami/mongodb
+
+# MONGODB_URL=mongodb://root:vocdoni@mongo:27017/
+
+volumes:
+  mongodb: {}