https://bugzilla.redhat.com/show_bug.cgi?id=1871452
Bug ID: 1871452 Summary: Review Request: ghc-atomic-write - Atomically write to a file Product: Fedora Version: rawhide Status: NEW Component: Package Review Assignee: nobody@fedoraproject.org Reporter: petersen@redhat.com QA Contact: extras-qa@fedoraproject.org CC: package-review@lists.fedoraproject.org Target Milestone: --- Classification: Fedora
Spec URL: https://petersen.fedorapeople.org/reviews/ghc-atomic-write/ghc-atomic-write.... SRPM URL: https://petersen.fedorapeople.org/reviews/ghc-atomic-write/ghc-atomic-write-...
Description: Atomically write to a file on POSIX-compliant systems while preserving permissions.
On most Unix systems, `mv` is an atomic operation. This makes it simple to write to a file atomically just by using the mv operation. However, this will destroy the permissions on the original file. This library does the following to preserve permissions while atomically writing to a file:
* If an original file exists, take those permissions and apply them to the temp file before `mv`ing the file into place.
* If the original file does not exist, create a following with default permissions (based on the currently-active umask).
This way, when the file is `mv`'ed into place, the permissions will be the ones held by the original file.
This library is based on similar implementations found in common libraries in Ruby and Python:
* <http://apidock.com/rails/File/atomic_write/class Ruby on Rails includes a similar method called atomic_write>
* <https://github.com/chef/chef/blob/c4631816132fcfefaba3d123a1d0dfe8bc2866bb/l... Chef includes atomic update functionality>
* <https://github.com/sashka/atomicfile There is a python library for atomically updating a file>
To use `atomic-write`, import the module corresponding to the type you wish to write atomically, e.g., to write a (strict) ByteString atomically:
import System.AtomicWrite.Writer.ByteString
Then you can use the atomicWriteFile function that accepts a `FilePath` and a `ByteString`, e.g.:
atomicWriteFile myFilePath myByteString.
Koji scratch build: https://koji.fedoraproject.org/koji/taskinfo?taskID=49980469