Data Transformation Pipeline Code

Architecture

Pipeline Components

Future ITS Owned Components:

• Harvester: ActivityStreams based record harvester that stores to a Cache.
• Cache: Record cache for storing local copies of JSON data. Currently postgres or filesystem.
• IdMap: Identifier Map that mints, manages and retrieves external/internal identifier sets. Currently redis or in-memory.

Pipeline Components:

• Config: Configuration as JSON records in a Cache.
• Collector: Recursively collects identifiers for a given record.
• Merger: Merges two Linked Art records representing the same entity together.
• Reidentifier: Recursively external rewrite URIs in a record to internal identifiers, given an IdMap.
• Sources/*/Fetcher: Fetches identified record from external source to a Cache.
• Sources/*/Mapper: Maps from external source into Linked Art.
• Sources/*/Reconciler: Determine if the entity in the given record is described in the external source.
• Sources/*/Loader: Load a dump of the data into the data cache.
• Sources/*/IndexLoader: Create an inverted index to reconcile records against this dataset.
• MarkLogic: Transformation from Linked Art into MarkLogic internal format.

External Sources: Implementation Status

Source	Fetch	Map	Reconcile	Load	IdxLoad
AAT	✅	✅	N/A	N/A	-
DNB	✅	✅	-	✅	-
FAST	✅	-	-	-	-
Geonames	✅	✅	-	N/A	-
LCNAF	✅	✅	-	-	-
LCSH	✅	✅	-	✅	✅
TGN	✅	✅	-	N/A	-
ULAN	✅	✅	-	N/A	-
VIAF	✅	✅	-	-	-
Who's on First	✅	✅	-	N/A	-
Wikidata	✅	✅	✅	✅	✅
Japan NL	✅	✅	-	N/A	-

✅ = Seems to work ; - = Not started ; N/A = Can't be done

• AAT, TGN, ULAN: Dump files are NTriples based. More effort to reconstruct than it would be worth.
• Geonames: Dump file is CSV without all the information (e.g. no language of names)
• WOF: Dump file is a 33Gb sqlite db... if it was useful, we could just use it as the cache
• LCNAF: Doesn't have the real world object data which we want, useful for reconciliation though
• VIAF: Too much data for not enough value
• FAST: Just not implemented yet (needs to process MARC/XML)

Fetching external source dump files

Process:

1. In the config file, look up dumpFilePath and remoteDumpFile
2. Go to the directory where dumpFilePath exists and rename it with a date (e.g. latest-2022-07)
3. execute wget <url> where <url> is the URL from remoteDumpFile (and probably validate it by hand online)
4. For wikidata, as it's SO HUGE, instead do: nohup wget --quiet <url> & to fetch it in the background so we can get on with our lives in the mean time.
5. Done :)