refactor media module, change --env to --root

This commit moves the media scanner out of the db module and into
a new module, media. We also change the --env parameter to --root,
which takes a path to a directory where the default configuration
and the transcoded media cache will live.

README.md

@@ -23,7 +23,8 @@ pip3 install https://github.com/evilchili/grooveondemand/releases/download/beta/
 ### 2. Generate the default configuration
 
 ```
-~/.local/bin/groove setup > ~/.groove
+mkdir ~/.groove
+~/.local/bin/groove setup > ~/.groove/defaults
 ```
 
 ### 3. Set the Media Root

groove/cli.py

@@ -23,8 +23,8 @@ from groove.console import Console
 SETUP_HELP = """
 # Please make sure you set MEDIA_ROOT and SECRET_KEY in your environment.
 # By default, Groove on Demand will attempt to load these variables from
-# ~/.groove, which may contain the following variables as well. See also
-# the --env paramter.
+# ~/.groove/defaults, which may contain the following variables as well. See
+# also the --root paramter.
 
 # Set this one. The path containing your media files
 MEDIA_ROOT=
@@ -32,6 +32,15 @@ MEDIA_ROOT=
 # the kinds of files to import
 MEDIA_GLOB=*.mp3,*.flac,*.m4a
 
+# If defined, transcode media before streaming it, and cache it to disk. The
+# strings INFILE and OUTFILE will be replaced with the media source file and
+# the cached output location, respectively.
+#
+TRANSCODER=/usr/bin/ffmpeg -i INFILE -c:v libvpx-vp9 -crf 30 -b:v 0 -b:a 256k -c:a libopus OUTFILE
+
+# where to cache transcoded media files
+CACHE_ROOT=~/.groove/cache
+
 # where to store the groove_on_demand.db sqlite database.
 DATABASE_PATH=~
 
@@ -56,12 +65,12 @@ app = typer.Typer()
 @app.callback()
 def main(
     context: typer.Context,
-    env: Optional[Path] = typer.Option(
+    root: Optional[Path] = typer.Option(
         Path('~/.groove'),
         help="Path to the Groove on Demand environment",
     )
 ):
-    load_dotenv(env.expanduser())
+    load_dotenv(root.expanduser() / Path('defaults'))
     load_dotenv(stream=io.StringIO(SETUP_HELP))
     debug = os.getenv('DEBUG', None)
     logging.basicConfig(

groove/path.py

@@ -4,7 +4,7 @@ import os
 from pathlib import Path
 from groove.exceptions import ConfigurationError, ThemeMissingException, ThemeConfigurationError
 
-_setup_hint = "You may be able to solve this error by running 'groove setup' or specifying the --env parameter."
+_setup_hint = "You may be able to solve this error by running 'groove setup' or specifying the --root parameter."
 _reinstall_hint = "You might need to reinstall Groove On Demand to fix this error."
 
 
@@ -27,11 +27,29 @@ def media_root():
     return path
 
 
+def cache_root():
+    path = os.environ.get('CACHE_ROOT', None)
+    if not path:
+        raise ConfigurationError(f"CACHE_ROOT is not defined in your environment.\n\n{_setup_hint}")
+    path = Path(path).expanduser()
+    if not path.exists() or not path.is_dir():
+        raise ConfigurationError(
+            "The cache_root directory (CACHE_ROOT) doesn't exist, or isn't a directory.\n\n{_setup_hint}"
+        )
+    logging.debug(f"Media cache root is {path}")
+    return path
+
+
 def media(relpath):
     path = media_root() / Path(relpath)
     return path
 
 
+def transcoded_media(relpath):
+    path = cache_root() / Path(relpath)
+    return path
+
+
 def static_root():
     dirname = os.environ.get('STATIC_PATH', 'static')
     path = root() / Path(dirname)

groove/shell/interactive_shell.py

@@ -1,7 +1,7 @@
 from slugify import slugify
 
 from groove.db.manager import database_manager
-from groove.db.scanner import MediaScanner
+from groove.media.scanner import MediaScanner
 from groove.shell.base import BasePrompt, command
 from groove.exceptions import InvalidPathError
 from groove import db

groove/webserver/requests.py

@@ -9,7 +9,7 @@ def encode(args: List, uri: str) -> str:
     Encode a request and cryptographically sign it. This serves two purposes:
     First, it enables the handler that receives the request to verify that the
     request was meant for it, preventing various routing and relay-induced bugs.
-    Second, it ensures the request wasn't corrutped or tampered with during
+    Second, it ensures the request wasn't corrupted or tampered with during
     transmission.
 
     Args:

test/test_scanner.py

@@ -5,7 +5,8 @@ from unittest.mock import MagicMock
 from sqlalchemy import func
 
 import groove.exceptions
-from groove.db import scanner, track
+from groove.media import scanner
+from groove.db import track
 
 
 def test_scanner(monkeypatch, in_memory_db):