Collections

<collections>
  <file>$HOME/dph_example_archive_VG2PLS/browse/Collection_browse.xml</file>
  <file>$HOME/dph_example_archive_VG2PLS/context/Collection_context.xml</file>
  <file>$HOME/dph_example_archive_VG2PLS/data/Collection_data.xml</file>
  <file>$HOME/dph_example_archive_VG2PLS/document/Collection_document.xml</file>
  <file>$HOME/dph_example_archive_VG2PLS/xml_schema/Collection_xml_schema.xml</file>
</collections>
        

Specify collection products here. This allows Harvest to be able to distinguish between primary members and secondary members of a collection while traversing a target directory.

Directories

<directories>
  <path>$HOME/dph_example_archive_VG2PLS</path>
  <fileFilter>
    <include>*.xml</include>
  </fileFilter>
</directories>
        

Specify the top level directory for Harvest to crawl for products to register.

Access URLs

<accessUrls harvest:registerFileUrls="false">
  <accessUrl>
    <baseUrl>http://starbase.jpl.nasa.gov</baseUrl>
    <offset>$HOME</offset>
  </accessUrl>
</accessUrls>
        

Specify the base URL of where the physical data products are located. This allows Harvest to provide links to the physical data products in the slots of each registered product in the Registry.

For the example above, if a bundle is online at http://starbase.jpl.nasa.gov/dph_example_archive_VG2PLS/

And on the machine you are running Harvest, the path to that bundle is $HOME/dph_example_archive_VG2PLS/

In order for Harvest to registry this product with this URL, we need to specify what path offset should be replaced with the baseUrl. In this case, the offset = $HOME, and the baseUrl is http://starbase.jpl.nasa.gov .

Checksums

<checksums harvest:generate="true">
  <manifest harvest:basePath="$HOME/dph_example_archive_VG2PLS">
    $HOME/dph_example_archive_VG2PLS/bundle_checksums.txt
  </manifest>
</checksums>
        

Specify a Checksum Manifest file. The basePath attribute is used to resolve relative file references, if found, within a Manifest file. If this attribute is not specified in the policy configuration file, the default behavior is to use the target directory as the base path. If there are multiple target directories specified, then it is required to explicitly specify a base path value in the policy.

With this configuration, Harvest will generate checksums for each file object to be registered and compare against the supplied checksums in the data product label as well as the manifest file.

Candidate Products

<candidates>

...

  <productMetadata harvest:objectType="Product_Browse">
    <xPath harvest:slotName="information_model_version">
      //Identification_Area/information_model_version
    </xPath>

...

<candidates>
        

Specify any additional product types for Harvest to register here. Note that Harvest reads in an internal global policy config which already includes the following product types:

• Product_Attribute_Definition
• Product_Bundle
• Product_Class_Definition
• Product_Collection
• Product_Context
• Product_Data_Set_PDS3
• Product_Instrument_Host_PDS3
• Product_Instrument_PDS3
• Product_Mission_PDS3
• Product_Subscription_PDS3
• Product_Target_PDS3
• Product_Volume_PDS3
• Product_Volume_Set_PDS3

Additionally, the candidates section in this policy config example already specifies the following product types:

• Product_Browse
• Product_Document
• Product_File_Text
• Product_Observational
• Product_XML_Schema

For the Product_Observational area:

<productMetadata harvest:objectType="Product_Observational">
  <!-- Identification_Area -->
  <xPath harvest:slotName="information_model_version">
    //Identification_Area/information_model_version
  </xPath>
  <xPath harvest:slotName="product_class">
    //Identification_Area/product_class
  </xPath>
  <xPath harvest:slotName="alternate_id">
    //Identification_Area/Alias_List/Alias/alternate_id
  </xPath>
  <xPath harvest:slotName="alternate_title">
    //Identification_Area/Alias_List/Alias/alternate_title
  </xPath>
  <xPath harvest:slotName="citation_author_list">
    //Identification_Area/Citation_Information/author_list
  </xPath>
...
</productMetadata>
        

add XPaths, as well as a meaningful slot name, for the <Discipline_Area> and <Mission_Area> metadata of interest to be included for every Product_Observational registration.

Note that the XPaths already defined in the example policy should not be modified as it allows the Registry to be populated with a consistent set of metadata for every product that is registered.

Namespaces

It is highly encouraged to define this in the policy when specifying XPaths to metadata that reside in a namespace other than the default PDS namespace. Doing so will make the policy more readable.

As an example, check out this PDS4 data product label here, which contains metadata within the <Discipline_Area> and <Mission_Area> sections that reside in namespaces other than the default PDS namespace. To extract metadata from these sections, do the following:

Set the namespaces in the candidates section of the policy config file:

<candidates>
  <namespace harvest:prefix="disp" harvest:uri="http://pds.nasa.gov/pds4/disp/v1"/>
  <namespace harvest:prefix="sp" harvest:uri="http://pds.nasa.gov/pds4/sp/v1"/>
  <namespace harvest:prefix="geom" harvest:uri="http://pds.nasa.gov/pds4/geom/v0"/>
  <namespace harvest:prefix="sbn" harvest:uri="http://pds.nasa.gov/pds4/sbn/v0"/>
  <namespace harvest:prefix="epoxi" harvest:uri="http://pds.nasa.gov/pds4/mission/epoxi/v0"/>

...

</candidates>
        

Then add the additional XPaths to extract metadata within the <Discipline_Area> and <Mission_Area> sections from Product_Observational products:

  <productMetadata harvest:objectType="Product_Observational">

...

    <!-- Mission_Area metadata -->
    <xPath harvest:slotName="spacecraft_clock_start_count">
      //Mission_Area/epoxi:EPOXI_Attributes/epoxi:Observation_Parameters/epoxi:spacecraft_clock_start_count
    </xPath>
    <xPath harvest:slotName="spacecraft_clock_stop_count">
      //Mission_Area/epoxi:EPOXI_Attributes/epoxi:Observation_Parameters/epoxi:spacecraft_clock_stop_count
    </xPath>
    <xPath harvest:slotName="total_integration_time">
      //Mission_Area/epoxi:EPOXI_Attributes/epoxi:Observation_Parameters/epoxi:total_integration_time
    </xPath>

    <!-- Discipline_Area metadata -->
    <xPath harvest:slotName="start_julian_date">
      //Discipline_Area/sbn:Times/sbn:start_Julian_date
    </xPath>
    <xPath harvest:slotName="display_settings_local_reference_type">
      //Discipline_Area/disp:Display_Settings/disp:Local_Internal_Reference/disp:local_reference_type
    </xPath>
    <xPath harvest:slotName="special_characteristics_local_identifier_reference">
      //Discipline_Area/sp:Spectral_Characteristics/sp:local_identifier_reference
    </xPath>
    <xPath harvest:slotName="geometry_vertical_display_direction">
      //Discipline_Area/geom:Geometry/geom:Image_Display_Geometry/geom:Display_Direction/disp:vertical_display_direction
    </xPath>
  </productMetadata>

</candidates>
        

Note that the XPaths are utilizing the prefix values from the namespaces defined in the policy.

Indexing more metadata

What gets indexed into the Registry and Search indexes is determined by a set of document generation configuration files. In the majority of use-case scenarios, the default set of configuration files provided in the conf/search/defaults directory is sufficient and is included by default, however you can also specify other config to pass into the tool using the -C, --doc-config flag option like so:

% harvest $HOME/directory -e "*.xml" -c ../conf/harvest/harvest-policy-master.xml -l harvest.log
        

The Harvest Tool package provides examples of how other document generation configuration files were set up to ingest bundles from various missions. They can be found in the conf/search directory. The following command demonstrates registering and indexing the MAVEN NGIMS bundle and post to the data collection:

% ./harvest -c ../conf/harvest/harvest-policy-maven-ngims.xml -C ../conf/search/maven-ngims \
-o $REGISTRY_HOME/../registry-data -l ../harvest-maven-ngims.log

% registry-mgr $REGISTRY_HOME/../registry-data
        

For more details on document generation configuration files, see the Search API Config Files Section.

Registering Products From Targets Specified In The Policy File

Targets can either be specified on the command-line or in in the policy file. Any targets specified on the command-line will overwrite any targets specified in the policy file. The following command demonstrates registering products based on targets specified in the policy file, policy.xml:

% ./harvest -c policy.xml
        

Registering Products From a Single Target

The following command demonstrates how to register products to a non-secured registry instance from a target directory, $HOME/directory, where only files that end with a .xml file extension, will be processed:

% ./harvest $HOME/directory -e "*.xml" -c policy.xml
        

Registering Products From Multiple Targets

The following command demonstrates how to register products to a non-secured registry instance from two target directories, $HOME/directory1 and $HOME/directory2, using the policy file, policy.xml. Only files that end with a .xml file extension will be processed. The output will go to a log file, log-file.txt:

% ./harvest $HOME/directory1, $HOME/directory2 -e "*.xml" -c policy.xml -l log-file.txt
        

Excluding Sub-Directories To Traverse From a Target

The following command demonstrates registering products from a target directory, $HOME/directory, where the tool will not traverse the sub-directory CONTEXT:

% ./harvest $HOME/directory -c policy.xml -D "CONTEXT"
        

Determine the Status of the Daemon Service

The following command is used to find out if the daemon service is still running:

% harvest-ctrl --url http://localhost:9001/xmlrpc --operation --isRunning
        

Shutdown the Daemon Service

The following command demonstrates shutting down the daemon service:

% harvest-ctrl --url http://localhost:9001/xmlrpc --operation --stop
        

registryPackage

Each time the Harvest Tool runs, it creates a package in the registry to group the product registrations together. Specify this element to give a registry package a name and/or description. The following table describes the elements that are allowed:

collections

Specify this element to tell the Harvest Tool to register the collections first before crawling a target directory. This is required if the target directory contains collections that are co-located with its members and in order to distinguish primary versus secondary members.

The following table describes the elements that are allowed:

In the example above, the Harvest Tool will register the following collections before crawling the target directory:

• $HOME/VG2PLS_archive/data/Collection_Data.xml
• $HOME/VG2PLS_archive/document/Collection_document.xml

Once these collections are registered, the primary and secondary members are cached in memory and as the Harvest Tool crawls through a target directory, any secondary members will be identified and will not be registered. In addition, a SKIP message will be issued in the log report to indicate that the tool has identified a non-primary member.

In the case where the target directory consists of a hierarchy structure where the collection product is located one-level above its members, much like the PDS context bundle, then there is no need to specify the collections in the Harvest policy config file. Under this scenario, the collections will be registered first before the Harvest Tool traverses down the sub-directory containing the members.

directories

Specify this element to tell the Harvest Tool where to crawl for data products. The following table describes the elements that are allowed:

In the example above, the Harvest tool will crawl the directory location, $HOME/VG2PLS_archive, looking for files that have a .xml file extension. The default is to touch all files in the directory if the filePattern element is omitted from the policy file. In addition, the CONTEXT directory will be ignored while traversing the target directory.

accessUrls

Specify this element to provide links to the physical data products. The links will be placed in the registry as slots under the slot name accessUrl. An optional attribute can be specified named registerFileUrls, which if set to true, will create file url links.

The accessUrls element can contain multiple accessUrl element tags. The following table describes the elements that are allowed within the accessUrl tag:

In the policy example above, the Harvest Tool will nix any absolute path of a product starting with $HOME before appending it to the starting base url of http://pds.nasa.gov/pds4. The following example demonstrates what the resulting access url will be for a registered product located at $HOME/VG2PLS_archive/browse/Collection_Browse.xml:

http://pds.nasa.gov/pds4/VG2PLS_archive/browse/Collection_Browse.xml
       

checksums

Checksum generation is turned off by default in the Harvest Tool. In order to turn this on, set the generate attribute to true. The following table describes the elements that are allowed within the checksum tag:

The following describes the tool behavior based on the different checksum settings:

Checksum Manifest File Provided and Generate Flag Set To true

Harvest will generate a checksum for each file encountered and verify it against the supplied checksum file. If the data file checksum was supplied in the label, Harvest will verify it as well. A warning message will be issued in the log report if a mismatch occurs. In any case, the generated checksum value is included in the associated Product_File_Repository product.

Checksum Manifest File Provided and Generate Flag Set To False (or not set at all)

Harvest will not generate checksums, but will use the value from the checksum manifest file to populate the associated Product_File_Repository product. If a data file checksum was supplied in the label, compare the value from the manifest against the value supplied in the label and issue a warning if there is a mismatch.

Checksum Manifest File Not Provided and Generate Flag Set To True

Harvest will generate a checksum for each file encountered and verify it against an optional checksum supplied in the label. If there is a mismatch, a warning message will be issued in the log report. The generated value is included in the associated Product_File_Repository product.

Checksum Manifest File Not Provided and Generate Flag Set To False

Harvest will not generate checksums. If the data file checksum was supplied in the label, populate the associated Product_File_Repository product with that value.

storageIngestion

Specify this element to tell the Harvest Tool to ingest data products to the PDS Storage Service. The following table describes the elements that are allowed:

In the example above, the Harvest Tool will ingest data products to the PDS Storage Service at http://localhost:9000. When a data product is ingested to the PDS Storage, it returns a product id which is a reference to the ingested product. This id is placed as a slot in the registry under the slot name storageServiceProductId.

candidates

Specify this element to tell the Harvest Tool what product types to register and what metadata to extract from a data product. This is a required element in the policy file. The following table describes the elements that are allowed:

By default, the Harvest Tool defines the default namespace to be the PDS namespace. To override this default, specify the default attribute in the namespace element and give it a value of true. The following sets the dph namespace to be the default namespace in Harvest:

<candidates>
  <namespace harvest:prefix="dph" harvest:uri="http://pds.nasa.gov/schema/pds4/dph/v01" harvest:default="true"/>
          ...
       

Namespaces need to be defined in the Harvest policy file only if the metadata to be extracted exists in a namespace other than the PDS namespace. In the example above, a namespace with the prefix dph and uri http://pds.nasa.gov/schema/pds4/dph/v01 has been defined. This means that any xPath expressions defined in the policy file will be able to use the dph prefix to be able to extract metadata that are within the dph namespace. xPaths will be explained in greater detail in the productMetadata section.

productMetadata

Specify this element to tell the Harvest Tool what metadata to register. It requires an attribute called objectType that tells the Harvest Tool what product types to register. The following table describes the elements that are allowed:

In the example above, the policy file tells the Harvest Tool to look for and register the Product_Document and Product_Observational object types.

Also in the example is a set of xPath elements found under each productMetadata element. This defines what metadata to extract from the different products. XPath is a query language that uses path expressions to select nodes in an XML document. These path expressions look very much like expressions in a traditional computer file system. In its simplest form, prepending a // before a name will find the element no matter where it is in the XML file.

The following XPath expression will find the start_date_time element within the default namespace, no matter where this element is located in the file:

//start_date_time
       

The following XPath expression will find the spacecraft_clock_start_count element within the dph namespace, no matter where this element is located in the file:

//dph:spacecraft_clock_start_count
       

The following XPath expression will find all information_model_version elements that are children of Identification_Area within the default namespace:

//Identification_Area/information_model_version
       

The following XPath expression will find all name elements that are children of Target_Identification and that have a value of MARS:

//Target_Identification/name[text()="MARS"]
       

For a more detailed explanation on XPath, go to your favorite search engine and type XPath tutorial.

The slotName attribute within the xPath element allows the renaming of metadata element names when they are registered as slots in the registry. By default, the slot name is set to the element name that results from an xpath expression. For example, for the xpath expression, //Target_Identification/name, the slot name will be set to name.

The following demonstrates setting the policy file to find any name elements that are children of Target_Identification and setting the slot name to target_identification_name:

<xPath harvest:slotName="target_identification_name">//Target_Identification/name</xPath>