Marc to Argot transformer

Converts MARC input to Argot, TRLN Discovery's shared ingest format.

The Argot format is documented at https://github.com/trln/data-documentation/tree/master/argot

1. Clone repo
2. bundle install
3. (optional) rake install - create and install the gem
4. (alternate) prepend all commands below with bundle exec

(3) installs the gem globally, e.g. puts the mta executable on your path, and may be appropriate for many circumstances; if you are developing this gem, and may want to compare different versions, etc. the bundle exec approach in (4) will probably serve your needs.

$ mta help create

List of options for the create command

$ mta create <collection> <input> <output>

1. <collection> = the name of the collection to use (e.g., asp | unc | duke | ncsu)
2. <input> = the input marc file
3. <output> = the output file

Spec files define the map between MARC fields and the Argot model. Each institution will manage their own spec file, located in lib/data/<inst>/marc_specs.yml. NOTE: Each attribute in the yaml file should either be an array of Marc specs OR a hash of nested attributes

• Array of marc values:

imprint:
  - 260abcefg
  - 262abcde
  - 264abc

• Nested values:

isbn:
  primary:
    - 020a
  other: 
    - 020z
    - 776z

• INCORRECT!!!

isbn: 020a

These spec files are uniquely configured to work with the argot/traject_config.rb file.

Each collection has a traject_config.rb file at lib/data/<collection name>/. This represents the processing of the marc fields to argot attributes.

argot/traject_config.rb is the centralized, agreed upon conventions for each institution, but can be overridden by a collection-specific configuration.

Basic overrides can be created in the form of an overrides.yml file in the collection folder (alongside the relevant traject_config.rb file). Keys appearing in the override file are ignored by the shared argot/traject_config.rb and left to be filled in by <collection name>/traject_config.rb

For example:

to_field "institution" do |rec, acc|
  inst = %w(unc duke nccu ncsu)
  acc.concat(inst)
end

to_field "institution", literal("duke")

- id
- institution
- items

In this example, any records processed in the duke collection will have their institution key in the output argot set to "duke".

Tests that involve checking that the results of transforming your institutional MARC to Argot are correct involve:

• Selecting a file containing representative record(s) in MARC format.
• copying that file with a meaningful name to spec/[collection]/[name].[extension]
• in your test (in spec/<collection name>/spec_(thing you are testing)rb) you can call TrajectRunTest.run_traject([collection], [name], [extension]) to get the result of running your collection's transformations on the relevant file as a string; use run_traject_json (with the same arguments) to parse the resulting string as JSON -- this is usually easier to work with.

Run tests with rspec, e.g.

$ bundle exec rspec

The Dockerfile in the directory specifies a container based on the official ruby images, defaulting to version 2.7. A simple build is thus:

$ docker build . -t mta:current

And run via

$ docker run -it --rm -v $(pwd):/app mta:current

All gems should be installed already by the build process, but note that the presence of a Gemfile.lock in the directory may interfere with that.

If you want to try your changes in a different version of Ruby, provide the RUBY_VERSION build arg:

$ docker build . --build-arg RUBY_VERSION=3.1 -t mta:current

See the Dockerfile for more details.