bcacheup: use nixstore.Open

go/nix/bcacheup/bcacheup.go

@@ -31,7 +31,6 @@ import (
 
 var (
 	blobURLFlag              = flag.String("cache_url", "", "Cache URL")
-	storeDBFlag              = flag.String("nix_store_db", nixstore.DefaultStoreDB, "Path to the nix store database")
 	stateSummaryIntervalFlag = flag.Duration("state_summary_interval", 10*time.Second, "Time between state summary outputs.")
 )
 
@@ -156,7 +155,7 @@ func (t *stateTracker) StateSummary() string {
 
 type uploader struct {
 	bucket    *blob.Bucket
-	store     *nixstore.DB
+	store     nixstore.Store
 	storePath string
 	st        stateTracker
 
@@ -421,7 +420,7 @@ func main() {
 	}
 	defer bucket.Close()
 
-	store, err := nixstore.Open(*storeDBFlag)
+	store, err := nixstore.Open()
 	if err != nil {
 		log.Fatalf("opening Nix store: %v", err)
 	}

go/nix/nixstore/default.nix

@@ -7,10 +7,13 @@ depot.third_party.buildGo.package {
   name = "nixstore";
   path = "hg.lukegb.com/lukegb/depot/go/nix/nixstore";
   srcs = [
+    ./nixstore.go
+    ./remotestore.go
     ./sqlitestore.go
   ];
   deps = with depot; [
     go.nix.nar.narinfo
+    go.nix.nixwire
     third_party.gopkgs."github.com".mattn.go-sqlite3
   ];
 }

go/nix/nixstore/nixstore.go

@@ -0,0 +1,26 @@
+package nixstore
+
+import (
+	"fmt"
+
+	"hg.lukegb.com/lukegb/depot/go/nix/nar/narinfo"
+)
+
+type Store interface {
+	NARInfo(storePath string) (*narinfo.NarInfo, error)
+	Close() error
+}
+
+func Open() (Store, error) {
+	s, errDmn := OpenDaemon(DaemonSock)
+	if errDmn == nil {
+		return s, nil
+	}
+
+	s2, errDB := OpenDB(DefaultStoreDB)
+	if errDB == nil {
+		return s2, nil
+	}
+
+	return nil, fmt.Errorf("failed to open daemon or DB: %v / %v", errDmn, errDB)
+}

go/nix/nixstore/sqlitestore.go

@@ -119,7 +119,7 @@ func (d *DB) Close() error {
 	return d.db.Close()
 }
 
-func Open(dbPath string) (*DB, error) {
+func OpenDB(dbPath string) (*DB, error) {
 	sqlDB, err := sql.Open("sqlite3", dbPath)
 	if err != nil {
 		return nil, err