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Grouper rules are configurable declarative scripts which run at certain times and perform actions on the registry.  They are similar to hooks though you dont have to write Java, and it does not require a change to a config file to enable a rule (i.e. anyone with authority in the folder hierarchy could enable a rule).

Use cases

Composite-ng: If an entity is no longer a member of the employee group, remove them from the group for application X

Disabled-date activation: If a student is no longer a member of the course X group, then change the membership of the course wiki group (if exists) for that user with end date in one week

Composite-org: If an entity falls out of any group in the IT organization groups, and is not a member of another group under the org folder (meaning not a central IT employee anymore), then remove them from group X

Inherited permissions: If a group is created under folder a:b, then apply privileges to the group of READ,UPDATE to group a:security:admins

Rule structure

The rule structure is custom for Grouper since we want it to be performant and secure, however it is inspired from drools.  There are several parts to a rule:

  • actAs: subject that the rule will act as.  If blank, then it will be filled in with the user who created the rule (probably a bad idea since the person might leave at some point, unless it is a service principal).  There can be configurations in the grouper.properties which allow users to act as other users or GrouperSysAdmin.
  • check:  this is when the rule is fired.  This will generally have a checkType, which tells grouper when to fire the check, and some data which narrows down the search.  e.g. checkType could be flattenedMembershipRemove, and the data could be groupName: a:b:c.  the data is stored in the checkOwner attribute
  • ifCondition: this might not be needed if the check contains all the information about when the rule should fire.  Otherwise you could put an EL here about something to check.  e.g. 
    ${!RulesUtils.hasMember(groupName, subjectSourceId, subjectId)}
  • then: this is a scriptlet or maybe some built in actions.  e.g. thenType is removeMember and groupName is a:b, or a scriptlet: 
    ${RulesUtils.removeMember(groupName, subjectSourceId, subjectId}

Rule check

The check component will see if the rule should continue to the "if condition".  The check part is an enum class: edu.internet2.middleware.grouper.rules.RuleCheckType

Look at the javadoc or source for the most recent check types, currently they are:

  • flattenedMembershipRemove
  • groupCreate
  • membershipRemove
  • stemCreate

Here is an example of setting a rule check:

AttributeAssign attributeAssign = groupA.getAttributeDelegate().assignAttribute(
    RuleUtils.ruleAttributeDefName()).getAttributeAssign();

attributeAssign.getAttributeValueDelegate().assignValue(RuleUtils.ruleCheckTypeName(), RuleCheckType.membershipRemove.name());

attributeAssign.getAttributeValueDelegate().assignValue(RuleUtils.ruleCheckOwnerNameName(), "stem:b");

The second part of the check is the owner.  This can either be set by name or id.  If the check is for objects in a folder or subfolder, there is also a stem scope attribute for ONE or SUB

Rule data

The rule will be an attribute of a grouper object (group, stem, etc).  There are attributes on the assignment which configure the params

    //add a rule on stem:a saying if you are out of stem:b, then remove from stem:a
    AttributeAssign attributeAssign = groupA
      .getAttributeDelegate().assignAttribute(RuleUtils.ruleAttributeDefName()).getAttributeAssign();

    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleActAsSubjectSourceIdName(), "g:isa");
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleActAsSubjectIdName(), "GrouperSystem");
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleCheckOwnerNameName(), "stem:b");
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleCheckTypeName(),
        RuleCheckType.membershipRemove.name());
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleIfConditionEnumName(),
        RuleConditionEnum.thisGroupHasImmediateMember.name());
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleThenElName(),
        "${ruleElUtils.removeMemberFromGroupId(ownerGroupId, memberId)}");

sadf

Error handling

If the rule execution fails for some reason, it should be logged (which could include emailing administrators), but it probably should not affect the transaction of the operation that triggered the rule.  Maybe this can be a setting on a per rule basis and where applicable (e.g. if it is a flattened membership rule trigger, then there is no transaction since the rule fires post commit anyways.

Act as

Note that the subject source should be set before the subject id or identifier (if the id or identifier arent unique).  Anyways, you can act as yourself, though I dont know why you would want to do that since if you leave the institution the rule might break.  You can configure in the grouper.properties what the act as rules are, similar to the grouper WS act as.

# Rules users who are in the following group can use the actAs field to act as someone else
# You can put multiple groups separated by commas.  e.g. a:b:c, e:f:g
# You can put a single entry as the group the calling user has to be in, and the grouper the actAs has to be in
# separated by 4 colons
# e.g. if the configured values is:       a:b:c, e:f:d :::: r:e:w, x:e:w
# then if the calling user is in a:b:c or x:e:w, then the actAs can be anyone
# if not, then if the calling user is in e:f:d, then the actAs must be in r:e:w.  If multiple rules, then
# if one passes, then it is a success, if they all fail, then fail.
rules.act.as.group = etc:rulesActAsGroup

Validation

There are certain validation constraints to make a rule valid.  i.e. you need some check, you need some then, you need an act as subject, etc.  So each time you change a rule attribute value, all the attributes are validated, and the attribute "ruleValid" is managed by that hook.  If the rule attributes are not valid, you will get a ruleValid value of something like: "INVALID: Rule check type required", if they are valid, then the value will be "T".  Only rules with a value of T will be processed.  The attribute stores this state so the rules dont have to be validated each time they are read from the DB, and so the user can get some feedback.

Logging

You can turn debug logging on to see information about rules which fire.  log4j.properties

 log4j.logger.edu.internet2.middleware.grouper.rules = DEBUG

If you want to only log certain rules, you can specify them in the grouper.properties.  (and you need to set the RulesEngine to INFO level at least)

# uuids (comma separated) of the attribute assign record which is the rule type to the owner object
# e.g. SELECT gaagv.attribute_assign_id FROM grouper_attr_asn_group_v gaagv WHERE gaagv.attribute_def_name_name LIKE '%:rule' AND gaagv.group_name = 'stem:a'
# make sure log info level is set for RuleEngine
# log4j.logger.edu.internet2.middleware.grouper.rules.RuleEngine = INFO
rules.attributeAssignTypeIdsToLog = 446bb6b3bbd8417b9a3e386b3bc894c1

You will see log messages like this:

2010-08-21 15:24:13,032: [main] INFO  RuleEngine.fireRule(248) - Rules engine processing rulesBean: group: stem:b, membership:
Membership[createTime=1282418648019,creatorUuid=8b10ad84a2ab4e4d912aeca154866bbc,depth=0,listName=members,listType=list,
memberUuid=ddbbbb1615964f109e4b5f85c05098f7,groupId=291dbf3b736e42de9985a70e2ac11177,type=immediate,
uuid=4f249fd2636247a78158fc358aa58a32:bb46e541e12049618c199e162056e715], subject: Subject id: test.subject.0, sourceId: jdbc, ,
found 1 matching rule definitions, ruleDefinition should fire: attributeAssignTypeId: 446bb6b3bbd8417b9a3e386b3bc894c1,
sourceId: g:isa, subjectId: GrouperSystem, checkOwnerName: stem:b, checkType: membershipRemove,
ifConditionEnum: thisGroupHasImmediateEnabledMembership, thenEl: ${ruleElUtils.removeMemberFromGroupId(ownerGroupId, memberId)}, ,
EL variables: membershipId(4f249fd2636247a78158fc358aa58a32:bb46e541e12049618c199e162056e715),groupId(291dbf3b736e42de9985a70e2ac11177),
groupName(stem:b),ruleElUtils,ownerGroupId(b38004ccf99d44f08f5a0971153ad6a9),subjectId(test.subject.0),memberId(ddbbbb1615964f109e4b5f85c05098f7),
checkOwnerName(stem:b),sourceId(jdbc),, elResult: true, shouldFire count: 1

Veto

You can have the "then" clause veto an action (if it is a transactional check), by using the grouper util veto EL method.  Note, if you are writing a custom EL class and want a veto, return the exception, dont throw it.  Also the exception should be a RuleVeto exception (which is runtime) or a subclass.  This example will veto an add to group A if the person is not a member of group B

    //act as GrouperSystem
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleActAsSubjectSourceIdName(), "g:isa");
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleActAsSubjectIdName(), "GrouperSystem");

    //fire the rule when a membership is added to group A
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleCheckOwnerNameName(), "stem:a");
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleCheckTypeName(),
        RuleCheckType.membershipAdd.name());

    //continue with the rule if the member is not a member of B
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleIfConditionEnumName(),
        RuleIfConditionEnum.groupHasNoImmediateEnabledMembership.name());
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleIfOwnerNameName(),
        "stem:b");

    //if we get this far, veto the action with a descriptive reason
    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleThenElName(),
        "${ruleElUtils.veto('rule.entity.must.be.a.member.of.stem.b', 'Entity cannot be a member of stem:a if not a member of stem:b')}");

Daemon

There is a daemon which runs on the loader which validates the rules and marks invalid ones as invalid.  Those need manual fixes to get them valid again (due to actas permissions).  You can configure the quartz cron in the grouper-loader.properties:

###################################
## Rules config
###################################

# when the rules validations and daemons run.  Leave blank to not run
rules.quartz.cron = 0 0 7 * * ?

The daemon will also run rule logic to sync up data inconsistencies (if it slipped by the rule somehow, or existed before the rule did).  The rule must be eligibile for daemon logic, meaning it must have an enum for the CHECK part, or either a blank or enum IF condition.  Also, the CHECK and IF enum must support daemon logic (basically it needs to be implemented), and the "ruleRunDaemon" attribute must be blank or T, and not F.

Extended EL API

There is a special group which has access to more objects in EL:

# any actAs subject in this group has access to more objects when the EL fires on
# the IF or THEN EL clause
rules.accessToApiInEl.group =

This is because the RuleUtils class might be too limiting in some cases, but if everyone had access to the API, it might not be secure.  So if you need this, configure a group here, put in trusted admins/users, then act as those users in your rule.  e.g.in this case the attributeAssignType object is in scope

    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleIfConditionElName(),
        "${ruleElUtils.hasMembershipByGroupId(attributeAssignType.getOwnerGroupId(), memberId, null, 'true')}");

Note, to see which objects are in EL scope, turn debug logging on for rules and check the logs

log4j.logger.edu.internet2.middleware.grouper.rules = DEBUG

Custom EL classes

You can configure custom EL classes to help with logic you need if not in the Grouper API.  Here is an example:

# put in fully qualified classes to add to the EL context.  Note that they need a default constructor
# comma separated.  The alias will be the simple class name without a first cap.
# e.g. if the class is test.Test the alias is "test"
rules.customElClasses = edu.internet2.middleware.grouper.rules.MyRuleUtils

Make a class:

/**
 * @author mchyzer
 * $Id: MyRuleUtils.java 6947 2010-08-23 15:33:36Z mchyzer $
 */
package edu.internet2.middleware.grouper.rules;

import org.apache.commons.logging.Log;

import edu.internet2.middleware.grouper.Group;
import edu.internet2.middleware.grouper.GroupFinder;
import edu.internet2.middleware.grouper.GrouperSession;
import edu.internet2.middleware.grouper.Member;
import edu.internet2.middleware.grouper.MemberFinder;
import edu.internet2.middleware.grouper.util.GrouperUtil;


/**
 *
 */
public class MyRuleUtils {

  /**
   * remove a member of a group
   * @param groupId
   * @param memberId
   * @return true if removed, false if not
   */
  public static boolean removeMemberFromGroupId(String groupId, String memberId) {
    if (LOG.isDebugEnabled()) {
      LOG.debug("Removing member: " + memberId + ", from group: " + groupId);
    }
    Group group = GroupFinder.findByUuid(GrouperSession.staticGrouperSession(), groupId, true);
    Member member = MemberFinder.findByUuid(GrouperSession.startRootSession(), memberId, true);
    boolean result = group.deleteMember(member, false);
    if (LOG.isDebugEnabled()) {
      LOG.debug("Removing subject: " + member.getSubjectId()
          + ", from group: " + group.getName() + ", result: " + result);
    }
    return result;
  }
  /** logger */
  private static final Log LOG = GrouperUtil.getLog(MyRuleUtils.class);


}

Use that in an EL:

    attributeAssign.getAttributeValueDelegate().assignValue(
        RuleUtils.ruleThenElName(),
        "${myRuleUtils.removeMemberFromGroupId(ownerGroupId, memberId)}");

sdf

To do:

  • document examples in GSH / API / shorthand for all use cases
  • add an API for easy rule assignment
  • rules on notification events
  • test the membership update, and other unit tests
  • add daemon for add groups with privs
  • gsh to run daemon part so that when rule is established, the daemon part syncs everything up
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