Hyrax Management Guide

cjcolvar edited this page Mar 2, 2018 · 32 revisions

The Hyrax Management Guide provides tips for how to manage, customize, and enhance your Hyrax application.

Feature matrix

Feature matrix (moved to its own page)

Production concerns

In production or production-like (e.g., staging) environments, you may want to make changes to the following areas.

Identifier state

Hyrax uses the ActiveFedora::Noid gem to mint Noid-style identifiers -- short, opaque identifiers -- for all user-created content (including GenericWorks, FileSets, and Collections). The identifier minter is stateful, meaning that it keeps track of where it is in the sequence of minting identifiers so that the minter can be "replayed," for example in a disaster recovery scenario. (Read more about the technical details.) The state also means that the minter, once it has minted an identifier, will never mint it again so there's no risk of identifier collisions.

Identifier state is tracked by default in a file that is located in a well-known directory in UNIX-like environments, /tmp/, but this may be insufficient in production-like environments where /tmp/ may be aggressively cleaned out. To prevent the chance of identifier collisions, it is recommended that you go one of two routes: specifying a less transient shared filesystem location or using a relational database to store minter state.

Filesystem-backed minter state

You can continue using the filesystem for minter state if you have a system location that your application can write to that is under its control (read: not /tmp/). If you are deploying via Capistrano, that location should not be in your application directory, which will change on each deployment. If you run multiple instances of your Hyrax application, for instance in load-balanced scenarios, you will want to choose a filesystem location that all instances can access. You may change this by uncommenting and changing the value in this line from config/initializers/hyrax.rb to a filesystem location other than /tmp/:

# config.minter_statefile = '/tmp/minter-state'

Database-backed minter state

Alternatively, to get around situations where you have multiple application instances attempting to obtain locks on a single, shared filesystem location, you may use the database-backed minter (new to ActiveFedora::Noid 2.x), which stores minter state information in your application's relational database.

To use it, you'll first need to run the install generator:

$ rails generate active_fedora:noid:install

This will create the necessary database tables and seed the database minter. To start minting identifiers with the new minter, override the AF::Noid configuration in e.g config/initializers/active_fedora-noid.rb:

require 'active_fedora/noid'

ActiveFedora::Noid.configure do |config|
  config.minter_class = ActiveFedora::Noid::Minter::Db
end

Using the database-backed minter can cause problems with your test suite, where it is often sensible to wipe out database rows between tests (which destroys the database-backed minter's state, which renders it unusable). To deal with this and still get the benefits of using the database-backed minter in development and production environments, you'll also want to add the following helper to your spec/spec_helper.rb:

require 'active_fedora/noid/rspec'

RSpec.configure do |config|
  include ActiveFedora::Noid::RSpec

  config.before(:suite) { disable_production_minter! }
  config.after(:suite)  { enable_production_minter! }
end

If you switch to the new database-backed minter and want to include in that minter the state of your current file-backed minter, AF::Noid 2.x provides a new rake task that will copy your minter's state from the filesystem to the database:

$ rails active_fedora:noid:migrate:file_to_database

Derivatives

In Hyrax, derivatives are served from a directory on the filesystem rather than directly from the Fedora repository. If your production environment includes multiple Rails servers, you will want to make sure that they are using a shared filesystem for derivatives. To set this directory, change the value of config.derivatives_path in config/initializers/hyrax.rb. The default value is tmp/derivatives/ within your application directory, which will cause unexpected behavior in a multi-server configuration, or if you deploy with capistrano.

Web server

The web server provided by Rails (whether that's WEBrick, Unicorn, or another) is not built to scale out very far, so you should consider alternatives such as Passenger with Apache httpd or nginx.

Slashes in Default Admin Set

If you encounter problems with the Default Admin Set and run Passenger or Apache, you may need to set the follow options in your configuration:

# Apache
AllowEncodedSlashes NoDecode
# Passenger
PassengerAllowEncodedSlashes on

Database

The database provided by default is SQLite, and you may wish to swap in something built more for scale like PostgreSQL or MySQL, both of which have been used in other production Hyrax applications.

Notifications

As mentioned in the README, Hyrax (as of version 2.0.0) uses a WebSocket-based user notification system, which uses Rails' ActionCable framework. There are known issues (upstream bug) with the WebSocket implementation in Passenger's Apache integration, so notifications will not work with that configuration. Note that Hyrax is smart enough to detect when it's been deployed via Passenger + Apache, and it will automatically disable realtime notifications for you so that it does not start up in a disabled state.

If user notifications are important to your application, consider serving the application via other methods, whether that be Puma, Passenger + Nginx, or Passenger Standalone via Apache reverse proxy. In the meantime, you may wish to disable realtime notifications at deploy time -- to do so, set config.realtime_notifications = false in config/initializers/hyrax.rb.

ActionCable can work with the Redis and PostgreSQL adapters (though notifications will not work with the async adapter, which is the default). See more about how to configure these adapters in the ActionCable documentation. To enable user notifications, make sure that you have configured ActionCable to use one of the above adapters in your application's config/cable.yml. E.g., to use the Redis adapter in the production Rails environment:

production:
  adapter: redis
  url: redis://yourhost.yourdomain.edu:6379

Mailers

Hyrax uses ActionMailer to send email to users. Some environments may need special configuration to enable your application to send messages. These changes are best made in one of your application's environment files. The configuration options are documented in the ActionMailer Rails Guide.

Background workers

Background Workers (moved to its own page)

Fixity checking

Hyrax provides a service that iterates over all file sets in your repository and verifies fixities in the background. Hyrax will not run this service for you, so you should use a cronjob (or similar, e.g., the whenever gem) to run this on a schedule that fits your needs and your content. The code that'll need to run is:

Hyrax::RepositoryFixityCheckService.fixity_check_everything

Virus checking

To turn on virus detection, install clamav on your system and add the clamav gem to your application's Gemfile:

gem 'clamav'

Image server

By default, as of version 2.1.0, Hyrax generates a working ruby IIIF ('RIIIF') configuration into your application but will not turn on the image server or use the UniversalViewer-enabled work show page. To enable both, you have two options. You can either use the built-in RIIIF server or you can use your own IIIF image server.

Note that in order to use the UniversalViewer in Hyrax, you will need to enable the public file server (which is very likely turned off in RAILS_ENV=production). This is a requirement of the pul_uv_rails dependency that we rely upon for the UniversalViewer: see https://github.com/pulibrary/pul_uv_rails/issues/8.

Option 1: Built-in RIIIF image server

To use the embedded image server, RIIIF, set config.iiif_image_server to true in config/initializers/hyrax.rb and restart your application. This assumes you have the RIIIF files Hyrax generates into your application. If you skipped this step earlier or missed it, run rails g hyrax:riiif. (Not sure if this has been done? Check to see that config/initializers/riiif.rb exists. If not, run the generator. If so, you should be good to go.)

Note about RIIIF In Production

In production environments using Apache and/or Passenger, you may need to add configuration so that RIIIF can resolve URLs. See the RIIIF README for guidance on this.

If you have explicitly URI-decoded the RIIIF url in config/initializers/riiif.rb per the RIIIF README, you may encounter authorization errors. In that case, you will also need to decode the object.id string in the Hyrax::IIIFAuthorizationService by overriding the #file_set_id_for method, like so:

  def file_set_id_for(object)
    if object.id.include? '/'
      object.id.split('/').first
    else
      URI.decode(object.id).split('/').first
    end
  end

Option 2: Custom image server

To use your own image server and avoid using RIIIF altogether, you should install Hyrax by passing the --skip-riiif flag to opt out of RIIIF. This applies to new Hyrax applications. If upgrading an existing Hyrax application, a manual, optional step is required to generate RIIIF into existing applications -- so, do not run this step if you prefer to use a custom image server instead of RIIIF. (If you change your mind later, you can always run rails g hyrax:riiif to pull in RIIIF as an image server.)

To make Hyrax use your custom image server, you should tweak the following configuration variables in config/initializers/hyrax.rb:

  • config.iiif_image_server must be set to true
  • config.iiif_image_url_builder must be set to a lambda/proc that takes three arguments and returns a valid link to an image request from your image server:
    • file_id, which looks like rv042t299%2Ffiles%2F6d71677a-4f80-42f1-ae58-ed1063fd79c7 (a path to a Hydra::PCDM::File within a Hydra::Works::FileSet)
    • base_url, which looks like http://your.site.edu/
    • size, which is a valid IIIF Image API size parameter
  • config.iiif_info_url_builder must be set to a lambda/proc that takes two arguments and returns a valid link to an IIIF image information request from your image server:
    • file_id, which looks like rv042t299%2Ffiles%2F6d71677a-4f80-42f1-ae58-ed1063fd79c7 (a path to a Hydra::PCDM::File within a Hydra::Works::FileSet)
    • base_url, which looks like http://your.site.edu/
  • config.iiif_image_compliance_level_uri must be set to a URI corresponding to a IIIF Image API compliance level
  • config.iiif_image_size_default must be set to a valid IIIF Image API size parameter

Disabling the image server

To switch off the image server, whether you're using RIIIF or a custom server, make the following change to config/initializers/hyrax.rb in your application:

config.iiif_image_server = false

You should also comment out all remaining config.iiif_* lines to return the application to its default status.

IIIF manifests

Hyrax provides IIIF manifests for all works by default, even when config.iiif_image_server is set to false. Note that these may not be very useful until backed by an image server.

Temp Directories

Cleaning up Temporary Directories and Files Due to the asynchronous nature of the ingest pipeline, Hyrax doesn't always clean up its own temp directories and files. It is, therefore, a good idea to do some out-of-band cleanup via a periodic task (such as a cron job). For example, the following shell command will clear out any files in /tmp over 1 megabyte in size that haven't been changed in the past 4 days:

$ find /tmp -ctime +3 -and -size +1M -delete

In a production environment, specifics such as the location of the temp directory, how often to clear it, and the age/size of the files to remove are system-dependent, so a proper cleanup strategy should be implemented in consultation with sysadmins and/or devops.

Translations

Hyrax ships with a user interface that has been translated into a number of languages (seven as of Nov. 2017). If your application uses Devise for authentication and you are seeing English strings even when Hyrax is showing strings in another language, you may use the devise-i18n gem to translate these strings. See the devise-i18n documentation for more information on how to do this.

Workflows

Read more about Defining a Workflow

Audiovisual transcoding

Hyrax includes support for transcoding audio and video files via Hyrax. View Hyrax README for installation/configuration help.

Removing a work type

If you need to remove a work type that you created, e.g., via rails generate hyrax:work MyWorkType, you can do so via:

rails destroy hyrax:work MyWorkType

And then manually remove the line that registers MyWorkType from config/initializers/hyrax.rb.

User interface

If you encounter problems with the in-browser content editor -- e.g., the About page, and the three blocks on the homepage -- you should remove turbolinks support from app/assets/javascripts/application.js if present by deleting the following line:

//= require turbolinks

Integration with Dropbox, Box, etc.

Hyrax provides built-in support for the browse-everything gem, which provides a consolidated file picker experience for selecting files from DropBox, Skydrive, Google Drive, Box, and a server-side directory share.

To activate browse-everything in your hyrax app, run the browse-everything install generator

rails g browse_everything:install --skip-assets

This will generate a file at config/browse_everything_providers.yml. Open that file and enter the API keys for the providers that you want to support in your app. For more info on configuring browse-everything, go to the project page on github.

After running the browse-everything install generator and setting the API keys for the desired providers, an extra tab will appear in your app's Upload page allowing users to pick files from those providers and submit them into your app's repository.

Administrative Set relationship

By default, Administrative Sets and their member objects use the Dublin Core Terms predicate isPartOf to express the membership relationship. Hyrax also allows use of a custom predicate for this relationship. To customize the predicate, point the Hyrax configuration option admin_set_predicate at another RDF term or a URI object.

(Note: allowing customization is the first step towards changing the default predicate for this relation. After the 2.0.0 release, Hyrax will warn users about using isPartOf for this purpose and add migration tooling for production instances using isPartOf. The default will change in Hyrax 3.0.0.)

Geonames

In order for autocomplete to work in the location field, you must have a valid geonames account that can query the service and return possible matches. To setup an account, visit: http://www.geonames.org/login.

After registering and getting an account username, you'll need to enable the free web services by going to http://www.geonames.org/manageaccount and clicking the link to enable. Once that's done, and you've verified you can query the service via their REST Api, add the account username to the config/initializers/hyrax.rb file under config.geonames_username.

Analytics and usage statistics

Hyrax provides support for capturing usage information via Google Analytics and for displaying usage stats in the UI.

Capturing usage and download counts

To enable the Google Analytics javascript snippet, make sure that config.google_analytics_id is set in your app within the config/initializers/hyrax.rb file. A Google Analytics ID typically looks like UA-99999999-1.

Displaying usage in the UI

To display data from Google Analytics in the UI, first head to the Google Developers Console and create a new project:

https://console.developers.google.com/project

Let's assume for now Google assigns it a project ID of foo-bar-123. It may take a few seconds for this to complete (watch the Activities bar near the bottom of the browser). Once it's complete, enable the Google+ and Google Analytics APIs here (note: this is an example URL -- you'll have to change the project ID to match yours):

https://console.developers.google.com/apis/library?project=foo-bar-123

Finally, click the 'credentials' menu item and create a new Service Account Key. This will give you the client ID, a client email address, a private key file, and a private key secret/password, which you will need in the next step.

Edit config/analytics.yml to reflect the information that the Google Developer Console gave you earlier; namely you'll need to provide it:

  • The path to the private key
  • The password/secret for the privatekey
  • The Service Account ID (email)
  • An application name (you can make this up)
  • An application version (you can make this up)

Lastly, you will need to set config.analytics = true and config.analytic_start_date in config/initializers/hyrax.rb and ensure that the client email has the proper access within your Google Analyics account. To do so, go to the Admin tab for your Google Analytics account. Click on User Management, in the Account column, and add "Read & Analyze" permissions for the OAuth client email address.

Populating the Analytics DB

TODO: Add more detail

The API access required in the UI integration step, above, enables more than just per-object stats display. We can harvest GA stats for all of our objects into the local database, and use this data to integrate usage reports into the Admin Statistics dashboard. So far this integration into the dashboard has not been done.

To harvest stats for all your objects, you might use a rake task that runs Sufia::UserStatImporter which in turn is called by a cron job.

Problems with Analytics

Having a problem setting up Analytics. See Analytics-workaround-for-non-production-environments, which documents a workaround for one known issue.

Zotero integration

Integration with Zotero-managed publications is possible using Arkivo. Arkivo is a Node-based Zotero subscription service that monitors Zotero for changes and will feed those changes to your Hyrax-based app. Read more about this work.

To enable Zotero integration, first register an OAuth client with Zotero, then install and start Arkivo-Hyrax and then generate the Arkivo API in your Hyrax-based application:

rails g hyrax:arkivo_api

The generator does the following:

  • Enables the API in the Hyrax initializer
  • Adds a database migration
  • Creates a routing constraint that allows you to control what clients can access the API
  • Copies a config file that allows you to specify the host and port Arkivo is running on
  • Copies a config file for your Zotero OAuth client credentials

Update your database schema with rails db:migrate.

Add unique Arkivo tokens for each of your existing user accounts with rails hyrax:user:tokens. (New users will have tokens created as part of the account creation process.)

Edit the routing constraint in config/initializers/arkivo_constraint.rb so that your Hyrax-based app will allow connections from Arkivo. Make sure this is restrictive as you are allowing access to an API that allows creates, updates and deletes.

Tweak config/arkivo.yml to point at the host and port your instance of Arkivo is running on.

Tweak config/zotero.yml to hold your Zotero OAuth client key and secret. Alternatively, if you'd rather not paste these into a file, you may use the environment variables ZOTERO_CLIENT_KEY and ZOTERO_CLIENT_SECRET.

Restart your app and it should now be able to pull in Zotero-managed publications on behalf of your users. Each user will need to link their Hyrax app account with their Zotero accounts, which can be done in the "Edit Profile" page. After the accounts are linked, Arkivo will create a subscription to that user's Zotero-hosted "My Publications" collection. When users add items to their "My Publications" collection via the Zotero client, they will automatically be pushed into the Hyrax-based repository application. Updates to these items will trigger updates to item metadata in your app, and deletes will delete the files from your app.

Customizing metadata

Chances are you will want to customize the default metadata provided by Hyrax. Here's a guide to help you with that in Hyrax.

Admin users

See making admin users in Hyrax.

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