Micro-services

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Archivematica implements a micro-service approach to digital preservation. The Archivematica micro-services are granular system tasks which operate on a conceptual entity that is equivalent to an OAIS information package: Submission Information Package (SIP), Archival Information Package (AIP), Dissemination Information Package (DIP). The physical structure of an information package will include files, checksums, logs, submission documentation, XML metadata, etc..

These information packages are processed using a series of micro-services. Micro-services are provided by a combination of Archivematica Python scripts and one or more of the free, open-source software tools bundled in the Archivematica system. Each micro-service results in a success or error state and the information package is processed accordingly by the next micro-service. There are a variety of mechanisms used to connect the various micro-services together into complex, custom workflows. Resulting in a complete ingest to access system.

Archivematica implements a default ingest to access workflow that is compliant with the ISO-OAIS functional model. Micro-services can be distributed to processing clusters for highly scalable configurations.

Contents

[edit] Current Micro-services in Archivematica

A micro-service may consist of a number of discrete tasks, or jobs. In the Archivematica dashboard, micro-services are always shown, while jobs may be viewed by expanding the micro-service (i.e. by clicking on the grey background behind the micro-service name).


Archivematica dashboard showing a micro-service and its jobs


The table below shows micro-services and jobs in the current release of Archivematica (Updated July 2015 for release 1.4.1).


[edit] Transfer

Micro-service Description
Approve Transfer
This is the approval step that moves the transfer into the Archivematica processing pipeline.
Verify transfer compliance


Set file permissions
Move to processing directory
Set transfer type: (Standard, Zipped bag, Unzipped bag, DSpace, Maildir)
Remove hidden files and directories
Remove unneeded files
Attempt restructure for compliance
Verify transfer compliance
Verify mets_structmap.xml compliance

Moves the transfer to a processing directory based on selected transfer type (standard, zipped bag, unzipped bag, DSPace export or maildir). Verifies that the transfer conforms to the folder structure required for processing in Archivematica and restructures if required. The structure is as follows: /logs/, /metadata/, /metadata/submissionDocumentation/, /objects/.
Rename with transfer UUID


Rename with transfer UUID

Directly associates the transfer with its metadata by appending the transfer UUID to the transfer directory name.
Include default Transfer processingMCP.xml


Include default Transfer processingMCP.xml

Adds a file named processingMCP.xml to the root of the transfer. This is a configurable xml file to pre-configure processing decisions. It can configure workflow options such as creating transfer backups, quarantining the transfer and selecting a SIP creation option.
Assign file UUIDs and checksums


Set file permissions
Assign file UUIDs to objects
Assign checksums and file sizes to objects

Assigns a unique universal identifier and sha-256 checksum to each file in the /objects/ directory and sets file permission to allow for continued processing.
Verify transfer checksums


Verify metadata directory checksums

Checks any checksum files that were placed in the /metadata/ folder of the transfer prior to moving the transfer into Archivematica.
Generate METS.xml document


Generate METS.xml document

Generates a basic METS file with a fileSec and structMap to record the presence of all objects in the /objects/ directory and their locations in any subdirectories. Designed to capture the original order of the transfer in the event the user chooses subsequently to delete, rename or move files or break the transfer into multiple SIPs. A copy of the METS file is automatically added to any SIP generated from the transfer.
Reformat metadata files


Process transfer JSON metadata

Transforms JSON metadata included with transfer to metadata.csv
Quarantine


Workflow decision - send transfer to quarantine
Move to quarantine
Remove from quarantine

Quarantines the transfer for a set duration, to allow virus definitions to update, before virus scan.
Scan for viruses


Scan for viruses

Uses ClamAV to scan for viruses and other malware. If a virus is found, the transfer is automatically placed in /sharedDirectoryStructure/failed/ and all processing on the transfer is stopped.
Generate transfer structure report


Generate transfer structure report
Move to generate transfer tree

Uses Tree to create transfer structure report (original order report) in txt format
Clean up names


Sanitize object's file and directory names
Sanitize Transfer name

Some file systems do not support unicode or other special characters in filenames. This micro-service removes prohibited characters and replaces them with dashes. Original filenames are preserved in the PREMIS metadata.
Identify file format


Move to select file ID tool
Select file format identification command
Determine which files to identify
Identify file format

Identifies formats of the objects in the transfer using either FIDO or file extension based on user choice. Format types are managed in the Format Policy Registry. This micro-service can be skipped and done in Ingest instead.
Extract packages


Move to processing directory
Move to extract packages
Extract packages? (preconfigured choice)
Delete package after extraction? (preconfigured choice)
Extract contents from compressed archives

Extracts objects from any zipped files or other packages. Extracts attachments from maildir transfers. User can preconfigure choices about whether to extract and whether to keep one or both of extracted object contents and/or the package itself.
Update METS.xml document


Add processed structMap to METS.xml document

Creates a structMap in the transfer METS to reflect structure of transfer
Characterize and extract metadata


Characterize and extract metadata
Load labels from metadata/file_labels.csv

Characterizes formats and extracts object metadata using File Information Tool Set (FITS), FFprobe, Exiftool and/or Mediainfo
Validation


Validate formats

Validates formats using JHOVE.
Examine Contents


Examine contents

Runs Bulk Extractor on transfer contents and creates reports
Complete transfer


Index transfer contents
Create transfer metadata XML
Move to SIP creation directory for completed transfers

Indexes transfer contents, creates transfer METS XML, then marks the transfer as complete.
Create SIP from Transfer


Check transfer directory for objects
Updating transfer file index
Create placement in backlog PREMIS events
Move transfer to backlog
Check transfer directory for objects
Load options to create SIP

This is the approval step that moves the transfer to the SIP packaging micro-services (Ingest) if user chooses to Create single SIP and continue processing. User can also choose to Send transfer to backlog at this time, which creates an associated PREMIS event.


[edit] Ingest

Micro-service Description
Approve SIP creation


Approve SIP creation
Create removal from backlog PREMIS events

Applies to SIPs that have been created from backlog. Approves creation of SIP, and creates PREMIS event for removal from backlog.
Verify transfer compliance


Verify mets_structmap.xml compliance

Verifies the METS from the transfer.
Verify SIP compliance


Set file permissions
Move to processing directory
Verify SIP compliance

Verifies that the SIP conforms to the folder structure required for processing in Archivematica. The structure is as follows: /logs/, /metadata/, /metadata/submissionDocumentation/, /objects/.
Rename SIP directory with SIP UUID


Rename SIP directory with SIP UUID
Check if SIP is from Maildir Transfer

Directly associates the SIP with its metadata by appending the SIP UUID to the SIP directory name and checks if SIP is from Maildir transfer type to determine workflow.
Include default SIP processingMCP.xml


Include default SIP processingMCP.xml

Copies the processing configuration file added to the transfer in Include default Transfer processingMCP.xml, above, to the SIP.
Remove cache files


Remove cache files

Removes any thumbs.db files.
Clean up names


Load Dublin Core metadata from disk
Sanitize SIP name
Set file permissions

Some file systems do not support unicode or other special characters in filenames. This micro-service removes prohibited characters and replaces them with dashes. Original filenames are preserved in the PREMIS metadata.
Normalize


Identify manually normalized files
Check for Service directory
Check for Access directory
Set remove preservation and access normalized files to renormalize link.
Grant normalization options for no pre-existing DIP
Move to workFlowDecisions-createDip directory
Find options to normalize as
Set resume link after tool selected
Move to select file ID tool
Select pre-normalize file format identification commant
Identify file format
Resume after normalization file identification tool selected
Normalize
Move to processing directory
Create DIP directory
Create thumbnails directory
Normalize thumbnails
Normalize access
Normalize preservation
Set file permissions
Remove files without linking information (failed normalization artifacts etc.)
Move to approve normalization directory
Approve normalization
Load post approve normalization link
Set resume link after handling any manually normalized files
Move to processing directory
Set file permissions
Load finished with manual normalized link

Determines which normalization options are available for the SIP and presents them to the user as choices. Normalizes (i.e. generates preservation and/or access copies) based on selection. Thumbnail files are also generated during this micro-service.
Process manually normalized files


Check for manual normalized files

Processed files manually normalized during processing
Add final metadata


Move to metadata reminder
Reminder: add metadata if desired
Set file permissions

Provides the operator a reminder to add metadata through the UI if desired.
Transcribe SIP contents


Transcribe SIP contents
Transcribe

Runs Tesseract OCR tool on any JPG or TIFF image files in SIP.
Process submission documentation


Copy transfer submission documentation
Check for submission documentation
Move submission documentation into objects directory
Assign file UUIDs to submission documentation
Assign checksums and file sizes to submissionDocumentation
Sanitize file and directory names in submission documentation
Scan for viruses in submission documentation
Select file format identification command
Identify file format
Characterize and extract metadata on submission documentation
Remove files without linking information (failed normalization artifacts etc.)

Processes any submission documentation included in the SIP and adds it to the /objects/ directory.
Process metadata directory


Copy transfers metadata and logs
Process JSON metadata
Move metadata to objects directory
Assign file UUIDs to metadata
Assign checksums and file sizes to metadata
Sanitize file and directory names in metadata
Scan for viruses in metadata
Identify file format of metadata files
Characterize and extract metadata on metadata files
Remove empty manual normalization directories

Processes metadata.
Verify checksums


Verify checksums generated on ingest

Verifies checksums generated on ingest
Generate AIP METS


Generate METS.xml document

Generates Archivematica AIP METS.xml document
Prepare DIP


Copy thumbnails to DIP directory
Copy METS to DIP directory
Copy preconfigured choice XML to DIP directory
Generate DIP
Copy OCR data to DIP directory
Set file permissions

Creates a DIP containing access copies of the objects, thumbnails and a copy of the METS file.
Prepare AIP


Check if DIP should be generated
Prepare AIP
Move to compressionAIPDecisions directory
Select compression algorithm
Select compression level
Compress AIP
Copy submission documentation
Create AIP pointer file
Set bag file permissions
Check if AIP is a file or directory
Removed bagged files

Creates an AIP in Bagit format. Creates the AIP pointer file. Indexes the AIP, then losslessly compresses it.
Upload DIP


Upload DIP

Allows the user to choose to upload the DIP AtoM, CONTENTdm, Archivist's Toolkit. Also allows user to store DIP or reject DIP.
Upload DIP to AtoM


Upload DIP
Move to the uploadedDIPs directory

The user uploads the DIP to a selected description in AtoM.
Upload DIP to CONTENTdm


Upload DIP
Restructure DIP for CONTENTdm upload
Move to the uploadedDIPs directory

The user creates a DIP suitable for upload to CONTENTdm using Project Client.
Upload DIP to Archivists' Toolkit


The user uploads the DIP metadata to Archivists' Toolkit
Store DIP


Upload DIP
Retrieve DIP Storage Locations
Store DIP location
Store DIP
Move to the uploadedDIPs directory

The user stores the DIP in a location pre-configured in the Storage Service.
Store AIP


Move to the store AIP approval directory
Store AIP
Retrieve AIP Storage Locations
Store AIP location
Move to processing directory
Verify AIP
Store the AIP
Index AIP
Clean up after storing AIP
Remove processing directory

Moves the AIP to /sharedDirectoryStructure/www/AIPsStore/ or another specified directory. Before the AIP has been stored, a copy of it is extracted to a local temp directory, where it is subjected to standard BagIt checks: verifyvalid, checkpayloadoxum, verifycomplete, verifypayloadmanifests, verifytagmanifests.

[edit] Historical Micro-services in Archivematica Releases

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