Only apply Litestream pragmas when Litestream is enabled (#342)

* Only apply Litestream pragmas when Litestream is enabled

Litestream has a set of SQLite pragmas it recommends, but we should only apply them when we're actually using Litestream. Otherwise, we should stick with the SQLite defaults.

* Use WAL mode regardless of Litestream

Author: mtlynch

cmd/picoshare/main.go

@@ -32,7 +32,7 @@ func main() {
 
 	ensureDirExists(filepath.Dir(*dbPath))
 
-	store := sqlite.New(*dbPath)
+	store := sqlite.New(*dbPath, isLitestreamEnabled())
 
 	collector := garbagecollect.NewCollector(store, *vacuumDb)
 	gc := garbagecollect.NewScheduler(&collector, 7*time.Hour)
@@ -68,3 +68,7 @@ func ensureDirExists(dir string) {
 		}
 	}
 }
+
+func isLitestreamEnabled() bool {
+	return os.Getenv("LITESTREAM_BUCKET") != ""
+}

store/sqlite/sqlite.go

@@ -31,31 +31,37 @@ type (
 	}
 )
 
-func New(path string) store.Store {
-	return NewWithChunkSize(path, defaultChunkSize)
+func New(path string, optimizeForLitestream bool) store.Store {
+	return NewWithChunkSize(path, defaultChunkSize, optimizeForLitestream)
 }
 
 // NewWithChunkSize creates a SQLite-based datastore with the user-specified
 // chunk size for writing files. Most callers should just use New().
-func NewWithChunkSize(path string, chunkSize int) store.Store {
+func NewWithChunkSize(path string, chunkSize int, optimizeForLitestream bool) store.Store {
 	log.Printf("reading DB from %s", path)
 	ctx, err := sql.Open("sqlite3", path)
 	if err != nil {
 		log.Fatalln(err)
 	}
 
 	if _, err := ctx.Exec(`
-PRAGMA temp_store = FILE;
-
--- Apply Litestream recommendations: https://litestream.io/tips/
-PRAGMA busy_timeout = 5000;
-PRAGMA synchronous = NORMAL;
-PRAGMA journal_mode = WAL;
-PRAGMA wal_autocheckpoint = 0;
+		PRAGMA temp_store = FILE;
+		PRAGMA journal_mode = WAL;
 		`); err != nil {
 		log.Fatalf("failed to set pragmas: %v", err)
 	}
 
+	if optimizeForLitestream {
+		if _, err := ctx.Exec(`
+			-- Apply Litestream recommendations: https://litestream.io/tips/
+			PRAGMA busy_timeout = 5000;
+			PRAGMA synchronous = NORMAL;
+			PRAGMA wal_autocheckpoint = 0;
+				`); err != nil {
+			log.Fatalf("failed to set Litestream compatibility pragmas: %v", err)
+		}
+	}
+
 	applyMigrations(ctx)
 
 	return &db{

store/test_sqlite/db.go

@@ -8,12 +8,14 @@ import (
 	"github.com/mtlynch/picoshare/v2/store/sqlite"
 )
 
+const optimizeForLitestream = false
+
 func New() store.Store {
-	return sqlite.New(ephemeralDbURI())
+	return sqlite.New(ephemeralDbURI(), optimizeForLitestream)
 }
 
 func NewWithChunkSize(chunkSize int) store.Store {
-	return sqlite.NewWithChunkSize(ephemeralDbURI(), chunkSize)
+	return sqlite.NewWithChunkSize(ephemeralDbURI(), chunkSize, optimizeForLitestream)
 }
 
 func ephemeralDbURI() string {