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B2SAFE metadata component

After the initial design and protoytpe, we have keep improving the component.

The current version is a proof of concept (PoC), which offers the following features:

• automatic generation of the manifest, using as starting point a description of the data-metadata relations expressed in json-ld format.
• validation of the manifest
• upload of the metadata to the graphDB
• versioning of the manifest
• comparison of the multiple versions of a manifest and update of the graph according to the differences between them

The current component works as an extension of the b2safe core package (https://github.com/EUDAT-B2SAFE/B2SAFE-core). So it cannot be deployed independently.

Configuration

The specific rule set for the metadata needs to be added to the iRODS configuration in /etc/irods/server_config.json.
The specific python scripts need to be linked under the iRODS path: /var/lib/irods/msiExecCmd_bin.
Assuming the component is deployed in the following path: /opt/eudat/b2safe-metadata, then a set of configuration files is placed under /opt/eudat/b2safe-metadata/conf. In particular:

• mets_factory.conf
• b2safe_neo4j.conf
• EudatControlledVocabulary.jsonld
• metadata.json

they must be modified according to the documentation.
Moreover the path to b2safe_neo4j.conf must be added in file the rulebase/metadata.re:
getMetadataConfParameters(*mdConfPath) { *mdConfPath="/opt/eudat/b2safe-metadata/conf/b2safe_neo4j.conf"; }

Quick start

Once configured the component can be used to publish the metadata to the local metadata store.
There are a couple of test scripts, which can be used to verify that the configuration is fine.
A typical workflow could be the following one:

• the user uploads a collection with the manifest,
• the B2SAFE administrator defines a cron job to execute periodically the rule to extract the system metadata (EUDATPushMetadata(*path, *queue) in the b2safe core component) and push them to a messaging system
• the B2SAFE administrator defines a cron job to execute periodically the rule (EUDATStoreMetadata(*collPath, *user)) to parse the manifest and create/update the graph in the graphDB (local metadata store)

The manifest can be written by the user or generated automatically, starting from the metadata.json, using the script cmd/mets_factory.py (see executable)

Future developments