A Connector is a Java class that supports the standard Open Connector Framework (OCF) APIs.   The Open Metadata Repository Services (OMRS) uses the following types of connectors:

  • OMRS Repository Connectors - providing a common interface to metadata repositories.
  • OMRS Audit Log Store - providing a common interface to an audit log destination.
  • OMRS Cohort Registry Store - providing a common interface to the cohort registry store that saves information about members of a cohort.
  • OMRS Archive Store - providing a common interface to Open Metadata Archives
  • OMRS Topic Connector - providing a common interface to an instance of the OMRS Topic.
  • OMRS Repository Event Mapper - providing a common API for specific implementations of OMRS Event Mappers to implement

 

 

OMRS Repository Connector Implementations

The OMRS Repository Connector API defines a call interface to create, search, query, update and delete metadata stored in a metadata repository.  The implementation of a specific OMRS connector determines which type(s) of metadata repository it is able to access.

Table 1 below lists the OMRS Repository Connectors that form part of the core open metadata capability:

ConnectorDescription
Enterprise OMRS Repository ConnectorThis connector can issue calls to multiple OMRS connectors and aggregate the results as if the metadata was stored in a single repository.  This is how metadata queries are federated across open metadata repositories.   Since all implementations of OMRS connectors have the same API, the Enterprise OMRS Connector is able to work will a heterogeneous collection of OMRS connectors.  It uses its configuration to create the appropriate instances of the OMRS connectors.
Local OMRS Repository ConnectorThis connector wraps a "real" repository connector (see table 2) and manages events and validation for this connector.
OMRS REST Repository ConnectorThis is the connector used by an open metadata repository to make a direct call to another open metadata repository through the OMRS REST API.  It is typically used by the Enterprise OMRS Connector described above.
Table 1: OMRS Repository Connectors providing core open metadata function

 

Table 2 shows the OMRS Repository Connectors that provide open metadata access to specific types of metadata repositories

 

ConnectorDescriptionJIRA
Atlas OMRS Repository ConnectorThis is the connector to a local Apache Atlas metadata repository.  It calls directly to Apache Atlas's internal interface for the metadata repository and as such is always deployed in an Apache Atlas Server. Unable to render Jira issues macro, execution error.
IGC OMRS Repository ConnectorThis is the connector for retrieving metadata from IBM’s Information Governance Catalog.   This connector translates the calls to its OMRS Connector API to IGC's REST API and then translates the results of these calls to appropriate responses on its API. Unable to render Jira issues macro, execution error.
In-memory OMRS Repository ConnectorThis connector provides a simple in-memory repository for testing/demos or small-scale environments where metadata is being managed remotely and cached locally. Unable to render Jira issues macro, execution error.
Table 2: OMRS Repository Connectors for specific metadata repositories

 

Every OMRS connector supports the Open Connector Framework (OCF).  This means that they use connections to define the network address and user credentials necessary to access a specific instance of a metadata repository.  Figure 1 shows some potential patterns for the use of OMRS Connectors to access different types of metadata repositories.  The letters above each pattern (A, ..., D) refer to the notes beside the diagram.

 

Figure 1: OMRS Connector Patterns

A

The Local Atlas OMRS Repository Connector is hosted in the Apache Atlas server and calls the local internal metadata repository API. Every Atlas server will have one of these connectors.
BThe OMRS REST Repository Connector translates calls to its repository interface to calls the OMRS REST API of a remote open metadata repository.  Apache Atlas servers support the OMRS REST API, and other Open Metadata native metadata repositories may also implement this interface too.
CMetadata repositories that have their own API can create a connector to translate OMRS calls to call to their API.  The IGC OMRS Repository Connector is an example of this type OMRS connector written to support a specific metadata repository that is not Apache Atlas.  This OMRS Connector will be included in the Apache Atlas build so it can be called directly from the Enterprise OMRS Connector rather than via a remote REST call.
DThe Enterprise OMRS Connector (see here for more details) converts each call to its repository connector interface to a call to each of the OMRS connectors that it is configured to work with (see OMRS Enterprise Connector Manager).  It then aggregates the results together to form the response to its call.

 

Together the OMRS Connectors provide a flexible way to make calls to many types of metadata repositories.  

 

 

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4 Comments

  1. Yao Li

    do we call all the OMRS Connector now "XXX Repository Connector"?

    1. Mandy Chessell

      yes - because OMRS has 6 different types of connectors so we need to distinguish between the different types.

  2. Yao Li

    In Figure 1, the description for C, it should be "it can be called directly from an OMAS API," instead of "and OMAS API"

    1. Mandy Chessell

      Fixed the text.  The diagrams on this page are out of date since we changed the design to have all OMASs call the Enterprise OMRS Connector.  I will update the diagrams once the OMRS code is complete.