Inverting deps on SQL, Log and MQ plugins to make them optional dependencies of extended servers, Removing some dead code that brought in unused dependencies Filtering out some non-linux transitive deps. (#1057)

* initial Db helper split - make SQL and datastore packages optional

* abstracting log store

* break out DB, MQ and log drivers as extensions

* cleanup

* fewer deps

* fixing docker test

* hmm dbness

* updating db startup

* Consolidate all your extensions into one convenient package

* cleanup

* clean up dep constraints

api/datastore/datastore.go

@@ -2,35 +2,49 @@ package datastore
 
 import (
 	"context"
-	"fmt"
 	"net/url"
 
+	"fmt"
 	"github.com/fnproject/fn/api/common"
 	"github.com/fnproject/fn/api/datastore/internal/datastoreutil"
-	"github.com/fnproject/fn/api/datastore/sql"
 	"github.com/fnproject/fn/api/models"
 	"github.com/sirupsen/logrus"
 )
 
+// New creates a DataStore from the specified URL
 func New(ctx context.Context, dbURL string) (models.Datastore, error) {
-	return newds(ctx, dbURL) // teehee
-}
-
-func Wrap(ds models.Datastore) models.Datastore {
-	return datastoreutil.MetricDS(datastoreutil.NewValidator(ds))
-}
-
-func newds(ctx context.Context, dbURL string) (models.Datastore, error) {
 	log := common.Logger(ctx)
 	u, err := url.Parse(dbURL)
 	if err != nil {
 		log.WithError(err).WithFields(logrus.Fields{"url": dbURL}).Fatal("bad DB URL")
 	}
 	log.WithFields(logrus.Fields{"db": u.Scheme}).Debug("creating new datastore")
-	switch u.Scheme {
-	case "sqlite3", "postgres", "mysql":
-		return sql.New(ctx, u)
-	default:
-		return nil, fmt.Errorf("db type not supported %v", u.Scheme)
+
+	for _, provider := range providers {
+		if provider.Supports(u) {
+			return provider.New(ctx, u)
+		}
 	}
+	return nil, fmt.Errorf("no data store provider found for storage url %s", u)
+}
+
+func Wrap(ds models.Datastore) models.Datastore {
+	return datastoreutil.MetricDS(datastoreutil.NewValidator(ds))
+}
+
+// Provider is a datastore provider
+type Provider interface {
+	fmt.Stringer
+	// Supports indicates if this provider can handle a given data store.
+	Supports(url *url.URL) bool
+	// New creates a new data store from the specified URL
+	New(ctx context.Context, url *url.URL) (models.Datastore, error)
+}
+
+var providers []Provider
+
+// AddProvider globally registers a data store provider
+func AddProvider(provider Provider) {
+	logrus.Infof("Adding DataStore provider %s", provider)
+	providers = append(providers, provider)
 }