* fix: write index.yaml file atomically
This refactors the already-existing `AtomicWriteFile` utility
to a central location and uses it to write index files
atomically.
This is done to avoid having half-written index files break
client requests.
Drive-bys:
- Add test for AtomicWriteFile.
- Add test IndexFile.WriteFile.
Signed-off-by: rabadin <rvbadin@gmail.com>
* Review fix: use RenameWithFallback instead of os.Rename
Signed-off-by: rabadin <rvbadin@gmail.com>
Co-authored-by: rabadin <rvbadin@gmail.com>
Raphaël