Windows CI caught the atomic replace failing with UnauthorizedAccessException:
renaming over a file is denied while another handle holds it open, however
generously that handle shares the file. In production the CLI, a second GUI
instance or a virus scanner can each hold Settings.json for a moment, so retry the
replace a few times before letting the caller see the failure. The previous
File.WriteAllText threw on the same holds, so this is strictly more forgiving.
ExternalReaderNeverSeesAPartiallyWrittenFile keeps a handle open almost
continuously, which no retry budget can outlast on Windows, so restrict it to unix
where it actually tests write atomicity. Write_SurvivesATemporarilyUnwritableDirectory
covers the retry instead by revoking write permission on the containing directory.
Co-authored-by: rmcrackan <rmcrackan@gmail.com>
File.WriteAllText truncates the destination before writing, so an interrupted
write leaves a half-written or empty Settings.json, and the in-process lock added
in the previous commit cannot help a reader in another process - the GUI and the
CLI share this file.
Route every write through Dinah.Core.IO.AtomicFileWriter, which writes a sibling
temp file, flushes to disk and renames it over the destination. Validate the temp
file parses as json before the swap, the same way JsonFilePersister<T> already
saves AccountsSettings.json, so a bad payload leaves the existing file untouched.
Co-authored-by: rmcrackan <rmcrackan@gmail.com>
Configuration.Instance is a process-wide singleton read and written from the UI
thread, BackgroundWorker callbacks and download workers at the same time, but
PersistentDictionary guarded only its file writes. Its two Dictionary caches were
touched without synchronization, so concurrent inserts eventually corrupted them
and threw "Operations that change non-concurrent collections must have exclusive
access" (issue #1959, reported from MainVM.UpdateCountsBw_Completed reading
AutoDownloadEpisodes while a second GetCounts pass ran).
Reads on the file were unguarded too: Exists/GetJObject could observe a partially
written Settings.json, and readFile responds to empty contents by rewriting the
file, so a reader racing a writer could scramble the settings on disk.
Take one lock across each operation's cache and file access, and keep logging
outside it by having writeFile report whether it rewrote the file.
Co-authored-by: rmcrackan <rmcrackan@gmail.com>
All processables are now created with an instance of Configuration, and they use that instance's settings.
Added Configuration.CreateEphemeralCopy() to clone Configuration without persistence.
- Add `LIBATION_FILES_DIR` environment variable to specify LibationFiles directory instead of appsettings.json
- OptionsBase supports overriding setting
- Added `EphemeralSettings` which are loaded from Settings.json once and can be modified with the `--override` command parameter
- Added `get-setting` command
- Prints (editable) settings and their values. Prints specified settings, or all settings if none specified
- `--listEnumValues` option will list all names for a speficied enum-type settings. If no setting names are specified, prints all enum values for all enum settings.
- Prints in a text-based table or bare with `-b` switch
- Added `get-license` command which requests a content license and prints it as a json to stdout
- Improved `liberate` command
- Added `-force` option to force liberation without validation.
- Added support to download with a license file supplied to stdin
- Improve startup performance when downloading explicit ASIN(s)
- Fix long-standing bug where cover art was not being downloading
- Added `MockLibraryBook` which contains factories for easily creating mock LibraryBooks and Books
- Added mock Configuration
- New `IPersistentDictionary` interface
- New `MockPersistentDictionary` class which uses a `JObject` as its data store
- Added `public static Configuration CreateMockInstance()`
- This method returns a mock Configuration instance **and also sets the `Configuration.Instance` property**
- Throws an exception if not in debug
- Updated all chardonnay controls to use the mocks in design mode. Previously I was using my actual database and settings file, but that approach is fragile and is unfriendly towards anyone else trying to work on it.
