1 files changed, 66 insertions, 0 deletions
diff --git a/bot/utils/persist.py b/bot/utils/persist.py
new file mode 100644
index 00000000..a60a1219
--- /dev/null
+++ b/bot/utils/persist.py
@@ -0,0 +1,66 @@
+import sqlite3
+from pathlib import Path
+from shutil import copyfile
+
+from bot.seasons.season import get_seasons
+
+DIRECTORY = Path("data")  # directory that has a persistent volume mapped to it
+
+
+def make_persistent(file_path: Path) -> Path:
+    """
+    Copy datafile at the provided file_path to the persistent data directory.
+
+    A persistent data file is needed by some features in order to not lose data
+    after bot rebuilds.
+
+    This function will ensure that a clean data file with default schema,
+    structure or data is copied over to the persistent volume before returning
+    the path to this new persistent version of the file.
+
+    If the persistent file already exists, it won't be overwritten with the
+    clean default file, just returning the Path instead to the existing file.
+
+    Note: Avoid using the same file name as other features in the same seasons
+    as otherwise only one datafile can be persistent and will be returned for
+    both cases.
+
+    Example Usage:
+    >>> import json
+    >>> template_datafile = Path("bot", "resources", "evergreen", "myfile.json")
+    >>> path_to_persistent_file = make_persistent(template_datafile)
+    >>> print(path_to_persistent_file)
+    data/evergreen/myfile.json
+    >>> with path_to_persistent_file.open("w+") as f:
+    >>>     data = json.load(f)
+    """
+    # ensure the persistent data directory exists
+    DIRECTORY.mkdir(exist_ok=True)
+
+    if not file_path.is_file():
+        raise OSError(f"File not found at {file_path}.")
+
+    # detect season in datafile path for assigning to subdirectory
+    season = next((s for s in get_seasons() if s in file_path.parts), None)
+
+    if season:
+        # make sure subdirectory exists first
+        subdirectory = Path(DIRECTORY, season)
+        subdirectory.mkdir(exist_ok=True)
+
+        persistent_path = Path(subdirectory, file_path.name)
+
+    else:
+        persistent_path = Path(DIRECTORY, file_path.name)
+
+    # copy base/template datafile to persistent directory
+    if not persistent_path.exists():
+        copyfile(file_path, persistent_path)
+
+    return persistent_path
+
+
+def sqlite(db_path: Path) -> sqlite3.Connection:
+    """Copy sqlite file to the persistent data directory and return an open connection."""
+    persistent_path = make_persistent(db_path)
+    return sqlite3.connect(persistent_path)