wip(22w8d): add sqlite abstraction

.gitignore

@@ -14,6 +14,7 @@ npm-debug.log
 yarn-error.log
 public/robots.txt
 __pycache__
+*.pyc
 
 # OS generated files #
 ######################

backup.py

@@ -1,4 +1,4 @@
-from src import SQLite, StorageClient
+from src import Database, StorageClient
 
-client = SQLite()
+client = Database()
 print("OK")

src/__init__.py

@@ -1,7 +1,7 @@
 from dotenv import load_dotenv
 
 from .glob import file_exists
-from .db import SQLite
+from .db import Database
 from .gcs import StorageClient
 
 if not file_exists(".env"):

src/db/__init__.py

@@ -1 +1 @@
-from .sqlite import SQLite
+from .database import Database

src/db/config.sql

@@ -1,14 +1,16 @@
 CREATE TABLE flags (
-    k text PRIMARY KEY, 
-    v real
+    k TEXT PRIMARY KEY, 
+    v INTEGER
 );
 
-CREATE TABLE fileindex (
-    anchor text PRIMARY KEY,
-    chksum text
+CREATE TABLE manifest (
+    anchor TEXT PRIMARY KEY,
+    mtime INTEGER,
+    chksum TEXT
 );
 
 INSERT INTO flags
 VALUES
     ("CALC_CHECKSUM", 1),
-    ("BUCKET_OK", 0);
+    ("BUCKET_OK", 0),
+    ("INIT", 1);

src/db/database.py

@@ -0,0 +1,11 @@
+from .sqlite import SQLite
+
+class Database(SQLite):
+    def __init__(self):
+        super().__init__()
+
+    def backup_candidate(self, anchor: str) -> bool:
+        sql = f"SELECT anchor, mtime, chksum FROM manifest WHERE anchor = '{anchor}'"
+        data = self.query(sql)
+
+        return True

src/db/sqlite.py

@@ -9,18 +9,32 @@ class SQLite():
         self.db = sqlite.connect(self.get_db_path())
         self.cursor = self.db.cursor()
 
-        self.init()
+        # Check if the database requires configuration
+        try:
+            db_exists = self.query("SELECT k FROM flags WHERE k = 'INIT'")
+            if not db_exists:
+                self.configure_db()
+        except sqlite.OperationalError:
+            self.configure_db()
+    
+    # Strip linebreaks from pretty-printed SQL
+    @staticmethod
+    def format_query(sql: str) -> str: 
+        return " ".join([s.strip() for s in sql.splitlines()])
 
+    # Run SQL query
     def query(self, sql: str):
-        result = self.cursor.execute(sql)
+        query = self.cursor.execute(sql)
+        result = query.fetchall()
 
-        if result.rowcount < 1:
+        if len(result) < 1:
             return False
         
         return result
 
+    # Get path to database file
     def get_db_path(self) -> str:
-        name = ".gcsarchive.db"
+        name = ".cloudbackup.db"
         path = os.getenv("SOURCE_FOLDER")
 
         # Append db file name if absent
@@ -31,17 +45,11 @@ class SQLite():
             path += name
         return path
 
+    # Prepare a fresh db with the expected table structure
     def configure_db(self):
         cwd = str(pathlib.Path(__file__).parent.resolve())
+
         sql = open(cwd + "/config.sql")
-        sql_str = sql.read()
+        sql_str = SQLite.format_query(sql.read())
 
         return self.cursor.executescript(sql_str)
-
-    def init(self):
-        # Set up db if it's fresh
-        hasmeta_sql = "SELECT name FROM sqlite_master WHERE type='table' AND name='flags'"
-        if not self.query(hasmeta_sql):
-            self.configure_db()
-
-        return True