bag-describe

A simple shell script that generates file format description data for all files in a BagIt bag.

Overview

This script calls upon an instance of the DAITSS Format Description Service to generate PREMIS records characterizing each file in a BagIt data directory. The resulting records are saved in a new tag directory named "premis" inside the bag's root.

This code is fairly trivial, and can be easily adapted to other use cases.

Setting up a local instance of the Format Description Service

The best way to use this script is to have a local instance of the Format Description Service running on your machine, though technically it doesn't matter what machine you run it on since all of the communication happens over HTTP.

These steps should help you to set up and run such an instance with minimal effort.

Requirements:

• Linux or Mac OSX
• RVM
• Java

(Before you begin: Make sure a Java JRE or JDK is installed somewhere and that the JAVA_HOME environment variable is set to the path where it is located.)

1. Open a Linux/Mac command line and cd into the directory where you want the description service to reside. (Inside of this directory is fine if you're not sure.)
2. curl -L https://github.com/daitss/describe/archive/5035ef1a9a4dd0aea1eedc3f4ad5e8a619974b95.tar.gz | tar zx
3. cd describe-5035ef1a9a4dd0aea1eedc3f4ad5e8a619974b95
4. rvm use 1.9.3
5. bundle install (you may run into issues here depending on your platform; refer to the README.md file in the describe-5035... directory for more information on setting up the Format Description Service if needed)
6. export DAITSS_CONFIG=daitss-config.example.yml
7. export VIRTUAL_HOSTNAME=describe.example.org
8. bundle exec thin start

Using the bag-describe shell script

If needed, edit the bag-describe file in this directory using a text editor and change the location specified on the line that reads

DESCRIBE_URL=http://localhost:3000

to the actual URL and port of your Description Service instance.

Then simply run

./bag-describe path/to/your/bag

to start the process. The resulting PREMIS records will be created in a new directory inside your bag's root called premis.

Using the bag-describe.py Python script

The Python script can be invoked as a standalone script with the following arguments:

• The URL to the description service
• The path to the bag

For example:

python bag-describe.py http://localhost:3000 path/to/your/bag

Note: The bag-describe.py module can also be imported into other scripts or applications. For example:

from bag-describe import bag-describe
...
bag_describe(description_url, bag_path)

License

See LICENSE.txt