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Applications and Real-Time Area
Applications Area Working GroupRFCRequest for CommentsI-DInternet-DraftBusiness Process ManagerPolicyBusiness RulesBusiness Rule ImplementationBusiness Rule Execution
This memo details the structure for implementing a process of routines or functions
that govern any generic task in order to achieve compliance to predefined
a technical framework.
A challenge facing most complex systems is an inherant inflexibility in the implementation
of dynamic legal and technical policies. When an industry is in constant
flux it can increase workload on developers to maintain the software
standards while still allowing for future extensibility. A formalised
policy document is a requirement in almost every industry however
conversion of the formalised policy document into working machine
code is a time consuming and tedious process, which is furthermore
fraught with hidden complexity and errors. The Policy Engine defined
in this document aims at alleviating the implementation of formalised
policy in a structured and concise format.
The Policy Engine is a structured XML document which contains a scriptable language
as a series of activities and logical branches. Compiled language
or compiled policy engine implementation falls out of the scope
of this document. The intention of the Policy Engine is to operate
on XML based payloads but this could be adapted to work on any
message format.
In order to deal with unknown requirements and future extensibility the Unix philosophy
was adopted. The following Unix philosophy rules (From Wikipedia)
should be assimilated when developing the policy code:
Rule of Modularity - Developers should build a program out of simple parts connected
by well defined interfaces, so problems are local, and parts
of the program can be replaced in future versions to support
new features.
Rule of Clarity - Developers should write programs as if the most important communication
is to the developer, including him- or herself, who will read
and maintain the program rather than the computer.
Rule of Separation - Developers should separate the mechanisms of the programs from
the policies of the programs; one method is to divide a program
into a front-end interface and back-end engine that interface
communicates with.
Rule of Simplicity - Developers should design for simplicity by looking for ways to
break up program systems into small, straightforward cooperating
pieces.
Rule of Parsimony - Developers should avoid writing big programs.
Rule of Economy - Developers should value developer time over machine time, because
machine cycles as of the year 2014 are relatively inexpensive
compared to prices in the 1970s.
The Policy Engine is assembled using parts of the Policy Code in an ordered and controlled
environment. Meta-Functions should be implemented in order to
traverse, invoke, or destroy current tasks.
The business rules are stored in a hierarchical structure as detailed below VARIABLES | LIBRARY DEFINITIONS | XPATH CONSTRAINTS |
| +-----------+---------------------+-------------------+
| +---------+
+----> OBJECTS |
+----+----+
| +--------+
+------> EVENTS |
+----+---+
| +------------+
+-----> ACTIVITIES <-----------------+
+------+-----+ |
| +--------+ |
| | LINE 1 | |
+-------> LINE 2 | |
| | LINE n | |
| +--------+ |
| +------------+ |
+-------> ACTIVITIES +--+
| +------------+ |
| XXXXXX |
| XX XX |
+------>XXX BRANCH XXX+-+
| XX XX
| XXXXXX
| +---------+
+-------> FINALLY |
+---------+
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Variables - Declared global variables which must be instantiated for each policy engine
instance
Library Definitions - A series of library imports with defined prefixes
XPath Constraints - A collection of XPath queries with the required minimum count,
maximum count, minimum length, maximum length, regular expression
match, and description fields.
Objects - A abstract base set of object names for example 'Domain', or 'Contact'
Events - The abstract base object event to be invoked for example 'Create', or 'Update'
Activities - A series of activities to perform in order of appearance
Line 1, Line 2, Line n - Lines of code either by library invocation or direct code
Child Activities - Nested child activities to perform, for semantic value only
Branch - A branch in order to separate logical program flow
Finally - A block of activities to perform even in the event of an exception in the
previous activities, used for cleaning up or handling an error
in a 'clean' mechanism
Conversion and implementation can begin as soon as a formalised policy document has
been released. The document should outline a clear process to adhere
to when performing a routine. Bullet point based procedures are
the easiest to implement on condition each bullet point defines
a single task to perform. Each bullet point should be able to be
converted into usable machine code known as Policy Code. The Policy
Engine can begin construction once the textual elements have been
converted to Policy Code.
(In no particular order)Ed PascoeDavid PeallVlad DinculescuTheo KramerA sample policy XML file built by a specialised user interfacemygtld[][][]5 days5 days5 days5 days5 daysPolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.domain_isAvailable(request)PolicyExec.domain_mandatoryValues(request)PolicyExec.validation(request)PolicyExec.checkBannedList(request.find(fns("{domain}name")).text,
banned_domain_list)PolicyExec.host_inbailiwickCheck(request)PolicyExec.domain_nameserverCheck(request)PolicyExec.contact_adjustState(clID, "Linked")PolicyExec.startTimer(request, "Domain",
"GracePeriod", \GracePeriod)PolicyExec.domain_statusCheck(request, ["Active",
"Ok"])PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.domain_exists(request)PolicyExec.domain_dependencyCheck(request)PolicyExec.startTimer(request, "Domain",
"PendingRelease", PendingReleasePeriod)PolicyExec.startTimer(request, "Domain",
"PendingTermination", PendingTerminationPeriod)PolicyExec.domain_statusCheck(request, ["Active",
"Ok"])PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.domain_exists(request)PolicyExec.domain_mandatoryValues(request)PolicyExec.validation(request)PolicyExec.host_inbailiwickCheck(request)PolicyExec.domain_nameserverCheck(request)PolicyExec.startTimer(request, "Domain",
"PendingUpdate", PendingUpdatePeriod)PolicyExec.domain_statusCheck(request, ["Active",
"Ok"])PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.domain_exists(request)PolicyExec.domain_isInGracePeriod(request)PolicyExec.domain_mandatoryValues(request)PolicyExec.validation(request)PolicyExec.startTimer(request, "Domain",
"PendingTransferUpdate", \PendingTransferUpdatePeriod)PolicyExec.domain_startTransfer(request, clID)PolicyExec.domain_adjustState(request, "Active")PolicyExec.domain_adjustState(request, "Active")PolicyExec.domain_adjustState(request, "Active")PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.contact_isAvailable(request)PolicyExec.contact_mandatoryValues(request)PolicyExec.validation(request)PolicyExec.checkBannedList(request, banned_contact_list)PolicyExec.contact_adjustState(clID, "Ok")PolicyExec.contact_statusCheck(request, ["Ok"])PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.contact_exists(request)PolicyExec.contact_dependencyCheck(request)PolicyExec.contact_adjustState(clID, "Deleted")PolicyExec.contact_statusCheck(request, ["Ok"])PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.contact_exists(request)PolicyExec.contact_mandatoryValues(request)PolicyExec.validation(request)PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.host_isAvailable(request)PolicyExec.host_mandatoryValues(request)PolicyExec.validation(request)PolicyExec.checkBannedList(request, banned_host_list)PolicyExec.host_inbailiwickCheck(request)PolicyExec.domain_nameserverCheck(request)PolicyExec.contact_adjustState(clID, "Linked")PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.host_exists(request)PolicyExec.host_dependencyCheck(request)PolicyExec.checkPermission(request, clID, objectname, eventname)PolicyExec.host_exists(request)PolicyExec.host_mandatoryValues(request)PolicyExec.validation(request)PolicyExec.host_inbailiwickCheck(request)PolicyExec.domain_nameserverCheck(request)
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The above is an example of an EPP Registry Implementation, note the use of the Library
Prefix as defined in the libraries section
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