In digital preservation work you sometimes may find yourself accepting a disk or random assortment of files, and want to examine all of them looking for duplicates and copy them to a new location in a uniform way, while preserving the original paths as metadata to help you process the data. Ok, maybe this is a bit of niche use case, but this is what dedoop was created for.
dedoop will recursively read a source directory of files and write them out to a new target directory or bucket in the cloud using the files's SHA256 checksum as the filename. If a given file occurs more than once in the source directory it will only be written once to the target location. File metadata such as the media type and original file name will be persisted in a JSON file that is output at the end of the process. In the case of writing to the cloud, object metadata will be used to store this information.
Install Python 3 and:
% pip3 install dedoop
To add a directory of data to the storage location you can:
% dedoop add path/to/source path/to/target
So for example if the source directory looks like this:
source
├── a.jpg
├── a.png
├── b.jpg
└── c
├── a.jpg
└── b.jpg
The resulting target could look like this (assuming the files of the same name had the same contents that hashed to these values):
target
├── 1e89b90b5973baad2e6c3294ffe648ff53ab0b9d75188e9fbb8b38deb9ba3341.png
├── 45d257c93e59ec35187c6a34c8e62e72c3e9cfbb548984d6f6e8deb84bac41f4.jpg
└── b6df8058fa818acfd91759edffa27e473f2308d5a6fca1e07a79189b95879953.jpg
You can also write files to any cloud storage provider that is supported by libcloud, such as Amazon S3, Google Cloud Storage, etc.
If you like you can limit the types of files that are added by using the --extensions command line option and giving it a comma separated list of file extensions to include. All non-matching files (case insensitive) will be ignored.
% dedoop add --extensions jpg,png path/to/source path/to/target
Its easy to list files on the file system. But its more difficult to see what's in the cloud--especially with the metadata dedoop has attached to each object. The list command will do that for you.
% dedoop ls s3://my-storage-location/
If you use --verbose you will see log messages on the console about what is happening. You can optionally send these messages to a log file of your choosing using the --log option.