Using ConnId Connectors in MidPoint

Last modified 22 May 2024 15:31 +02:00
Table of Contents

ConnId

ConnId is a framework that does most of the provisioning operations in midPoint.

Please see ConnId Connector Framework page for introduction to ConnId framework, basic concepts and framework history.

This page is targeted at connector developers, or engineers that are using custom connectors. For general advice on using stock connectors in midPoint, please see Connector Setup.

Connector Identification

ConnId connector is identified by a triple consisting of:

  • Bundle name which is usually in a form of maven group or java package name, such as com.evolveum.polygon.connector-ldap.

  • Bundle version which is usually a "dotted decimal" notation. ConnId is using four version numbers (e.g. 1.4.2.0). First three numbers are usual version numbers following semantic versioning conventions. The last number in version number indicates a "build" of a connector. This is derived from the source code control system. Official releases have the last number set to zero.

  • Connector type which is usually in a form of fully qualified Java class name, e.g. com.evolveum.polygon.connector.ldap.LdapConnector.

Connector Configuration Schema

Each connector has its configuration. The configuration can be discovered by the ConnId framework. When midPoint detects the connector, it reads the connector configuration schema, transforms it to Prism schema format and stores it in midPoint ConnectorType object. The schema is used by midPoint to configure connector instances.

Please see Resource and Connector Schema Explanation for the details.

Connector configuration properties are different for each connector. However, there are also configuration items that are common for all ConnId connectors. These are configuration of connector pool and operation timeouts.

ConnId framework provides connector pooling functionality. Connector pool parameters can be configured for each connector using connectorPoolConfiguration container:

    <connectorConfiguration xmlns:icfc="http://midpoint.evolveum.com/xml/ns/public/connector/icf-1/connector-schema-3">
        <icfc:connectorPoolConfiguration>
            <icfc:maxObjects>100</icfc:maxObjects>
        </icfc:connectorPoolConfiguration>
          ...
    </connectorConfiguration>

Similarly, operation timeouts can be configured using timeouts container.

Connectors and Resource Schema

The schema operation of the connector produces connector schema, in a ConnId-specific language. MidPoint transforms the result into Prism schema, and stores it in the resource object. Such resource schema describes object classes and attributes that can be handled by the connector.

Please see Resource and Connector Schema Explanation for the details.

ConnId __NAME__ and __UID__

There are some peculiarities when it comes original Identity Connector Framework (ICF) developed by Sun Microsystems back in 2000s. As ConnId framework is built on Sun ICF, we have to live with it. ICF mandates that all resource objects must have two special attributes: __NAME__ and __UID__. We do not like the underscores, and therefore we usually refer to them as ICF NAME and ICF UID. Their meaning is as follows:

Description Required for Typical usage ICF representation XML representation

ICF NAME

Represents user-friendly identifier of an object on a target resource. It should be human-readable, and it is used to create a resource object (e.g. account username). It is the name of the object that humans usually care about.

create

username,
LDAP DN

__NAME__

icfs:name

ICF UID

Represents the unique identifier of an object within the name-space of the target resource. Should be immutable if possible. It is returned from the create operation and must be used for other operations to identify the object. This may not be human-readable and is often (pseudo-randomly) generated. This is the identifier of an object that machines usually care about.

get, modify, delete

Entry UUID,
auto-generated ID column,
record number

__UID__

icfs:uid

For some simple resources the __UID__ and __NAME__ may be the same. Also do not confuse the ICF __UID__ with other attributes that may be named "uid" such as LDAP uid which is a part of inetOrgPerson schema. ICF __UID__ is a separate and quite powerful concept which needs some time to get used to. In the early phases of the learning curve it helps to think about it simply as an identifier of a resource object.

Confusingly enough, ICF __NAME__ and __UID__ usually take place of another account attributes. E.g. in "smart" LDAP deployment, the ICF __NAME__ usually contains distinguished name (dn) and ICF __UID__ usually contains the data from entryUuid LDAP attribute. This is an excellent setup to support object renames and moves which are surprisingly common in IDM deployments. It also means that there will be no dn and entryUuid attributes seen in the legacy resource schema. There will be icfs:name and icfs:uid instead. This "hiding" of such very important attributes is very difficult to get used to.

XML representation of the objects is using URIs instead of arbitrary prefixes (such as underscores) to denote namespaces. Therefore the XML representation of ICF NAME and UID is icfs:name and icfs:uid (icfs is a namespace prefix that refers to actual URL). Please take care not to confuse this with an actual attribute named "uid" such as LDAP uid. The attribute is using a different namespace and is usually denoted ri:uid.

Luckily, Evolveum team has improved the ConnId framework to support "native" attribute names. Due to the Sun’s legacy, the connector must still use the __NAME__ and __UID__ monstrosities. However, the connector can indicate that the real name of the __NAME__ name attribute is different. E.g. LDAP connector can indicate that the __NAME__ in fact means dn. MidPoint will take the hint, and it will use dn instead of the __NAME__. Therefore, the __NAME__ and __UID__ ugliness can be hidden from the end users. Unfortunately, connector developer still needs to be aware of it, and live with it.

This is still not used by all the connectors. Therefore, there still can be icfs:name and icfs:uid in the schema for some connectors. However, there is at least a mechanism that can hide the old mistakes.

ICF NAME and ICF UID attributes may be "renamed" to a more user-friendly names using displayName clause in Resource Schema Handling. This does not change the true nature of the attributes nor does it change the XML representation. It may improve user experience.

ConnId Issues

Although there are several known and painful issues in Identity Connector Framework design, they are not critical. There are many exiting ICF-comaptible connectors developed by several independent companies in the scope of several projects. The benefits of ICF compatibility greatly outweighs the drawbacks. Therefore we have chosen to stick with ConnId as the primary provisioning framework in midPoint, and keeping ConnId 1.x strictly compatible with the original Sun Identity Connector Framework.

Evolveum is actively contributing to ConnId development, being one of the most prominent contributors. Our goal is to evolve the framework and resolve most of the original ICF issues. There is already a plan for ConnId version 2.

ConnId Framework Logging

Useful information may also be provided by the logging the operations of the ConnId connector framework. This is very useful in cases that a suspected problem is in the interpretation of the values (e.g. data type conversions). This logs all the communication between connector, connector framework and midPoint. It can be enabled by setting the logging to:

org.identityconnectors.framework.api: TRACE

See Also

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