path: root/docs/Filter/Filter.rst

=======
Filter
=======

A filter examine an event and decides if it matches or doesn't.  Filters
are mainly used in rules to decide if the processing entries should be
executed on the given event. They're also used for settings, and systems
like the Graph Correlator re-use Highland Park's filter mechanism to
specify which alarms fit in a correlation.  Some publishers may produce
topics with a lot of volume and a subscriber may want only a portion of
those messages. The subscriber can certainly filter messages after
receiving them, but it may be substantially more efficient to ask the
API server to filter the messages before sending them to the
subscriber.The standard library includes a number of simple filters. The
Equals filter, for example, compares a field's value with some other
value and returns true if the values match.  The standard library also
includes filter classes called And, Or, and Not, so you can compose more
complex filters. For example, written in the standard JSON config
format:

+-----------------------------------------+
| "filter":{                              |
| "class":"And",                          |
| "filters":                              |
| [                                       |
| { "class":"Equals", "foo":"abc" },      |
| { "class":"Assigned", "field":"bar" }   |
| ]                                       |
| }                                       |
+-----------------------------------------+

- This filter matches events in which the field "foo" has value "abc"
  and the field "bar" is assigned to some value (as opposed to not being
  present on the event). Filters are used by the consumers to filter out
  data and consume only specific set of data which matches the
  conditions mentioned in filter. Filters can be passed as a query
  parameter by the consumer in consume request as mentioned below:
  **http://localhost:8080/DMaaP/dmaaprest/events/DMaaP/consumergroup/mHOeNFY4XiWx4CBa?filter=\\{"class":"Equals",
  "field":"email", "value":"test@abc.com" }**
- Filters can be applied only on data in JSON format i.e. if applied,
  filters will automatically ignore any non-json data.  While consuming,
  request CONTENT\_TYPE is not relevant to filter.

All the supported filter can be found below.

Types of Filters
----------------

- DMaaP Message Router supports all the filters which were supported by
  DMaaP Message Router and are mentioned below:-
- **All Alarms:**
  - Match all alarms.
- **And:**
  - Create a set of filters. This filter matches when all of them matches.

+-------------+--------------------+------------+---------------------+
| **Field**   | **Description**    | **Type**   | **Notes**           |
+=============+====================+============+=====================+
| filters     | Combined Filters   | LIST       | A list of filters   |
+-------------+--------------------+------------+---------------------+
|             |                    |            |                     |
+-------------+--------------------+------------+---------------------+

- **Assigned:**
  - Choose a field from the event to check for assignment. This filter
  matches when the field is assigned.

+-------------------+--------------------------------------------------------+------------+-----------------+
| **Field**         | **Description**                                        | **Type**   | **Notes**       |
+===================+========================================================+============+=================+
| field             | The field to check for on the event.                   | STRING     | A field name    |
+-------------------+--------------------------------------------------------+------------+-----------------+
| emptyIsAssigned   | If true, an empty value is considered an assignment.   | BOOLEAN    | True or False   |
+-------------------+--------------------------------------------------------+------------+-----------------+

- **Contains:**
   - Check if a search string contains another string.

+-------------+---------------------------------------------------+------------+--------------+
| **Field**   | **Description**                                   | **Type**   | **Notes**    |
+=============+===================================================+============+==============+
| String      | The value to search. Supports ${} notation.       | STRING     | Any string   |
+-------------+---------------------------------------------------+------------+--------------+
| Value       | The value to search for. Supports ${} notation.   | STRING     | Any string   |
+-------------+---------------------------------------------------+------------+--------------+
|             |                                                   |            |              |
+-------------+---------------------------------------------------+------------+--------------+

-  **EndsWith**:
   -  Check if a search string ends with another string.

+-------------+---------------------------------------------------+------------+--------------+
| **Field**   | **Description**                                   | **Type**   | **Notes**    |
+=============+===================================================+============+==============+
| string      | The value to search. Supports ${} notation.       | STRING     | Any string   |
+-------------+---------------------------------------------------+------------+--------------+
| value       | The value to search for. Supports ${} notation.   | STRING     | Any string   |
+-------------+---------------------------------------------------+------------+--------------+

-  **Equals:**

  - Choose a field from the event and a value to check for equality.

+-------------+----------------------------------------------+------------+--------------+
| **Field**   | **Description**                              | **Type**   | **Notes**    |
+=============+==============================================+============+==============+
| field       | The field to check. Supports ${} notation.   | STRING     | Any string   |
+-------------+----------------------------------------------+------------+--------------+
| value       | The value to match. Supports ${} notation.   | STRING     | Any string   |
+-------------+----------------------------------------------+------------+--------------+

-  **FlatironObjectExists**

  -  Matches when the given object exists in the given Flatiron instance.

+-------------+---------------------------------------------+------------+--------------+
| **Field**   | **Description**                             | **Type**   | **Notes**    |
+=============+=============================================+============+==============+
| oid         | The OID of the object to look for.          | STRING     | Any string   |
+-------------+---------------------------------------------+------------+--------------+
| flatiron    | The name of the Flatiron client instance.   | STRING     | Any string   |
+-------------+---------------------------------------------+------------+--------------+

- **IsAging**
  -  Choose a field to test. This filter matches if the expression is
  numeric.

+-------------+---------------------------------------------+------------+--------------+
| **Field**   | **Description**                             | **Type**   | **Notes**    |
+=============+=============================================+============+==============+
| field       | The field to test. Supports ${} notation.   | STRING     | Any string   |
+-------------+---------------------------------------------+------------+--------------+

- **IsNumeric**
  - Choose a field to test. This filter matches if the expression is
  numeric.

+-------------+---------------------------------------------+------------+--------------+
| **Field**   | **Description**                             | **Type**   | **Notes**    |
+=============+=============================================+============+==============+
| field       | The field to test. Supports ${} notation.   | STRING     | Any string   |
+-------------+---------------------------------------------+------------+--------------+

- **MathCondition**
  - Choose a field from the event and a value for logical math conditions.

+-------------+-------------------------------------------------+------------+-----------------------------------+
| **Field**   | **Description**                                 | **Type**   | **Notes**                         |
+=============+=================================================+============+===================================+
| Field       | The field to check. Supports ${} notation.      | STRING     | Any string                        |
+-------------+-------------------------------------------------+------------+-----------------------------------+
| Value       | The value to consider. Supports ${} notation.   | STRING     | Any string                        |
+-------------+-------------------------------------------------+------------+-----------------------------------+
| operator    | The operation.                                  | STRING     | One of { "<=", ">=", ">", "<" }   |
+-------------+-------------------------------------------------+------------+-----------------------------------+
|             |                                                 |            |                                   |
+-------------+-------------------------------------------------+------------+-----------------------------------+

- **NoAlarms**
  -  Don't match any alarms.
- **Not**
  -  Negate the configured filter.

+-------------+-------------------------+------------+-------------+
| **Field**   | **Description**         | **Type**   | **Notes**   |
+=============+=========================+============+=============+
| filter      | The filter to negate.   | FILTER     | A filter    |
+-------------+-------------------------+------------+-------------+

- **NotEqual**
  -  Choose a field from the event and a value to check for inequality.

+-------------+----------------------------------------------+------------+--------------+
| **Field**   | **Description**                              | **Type**   | **Notes**    |
+=============+==============================================+============+==============+
| field       | The field to check. Supports ${} notation.   | STRING     | Any string   |
+-------------+----------------------------------------------+------------+--------------+
| value       | The value to match. Supports ${} notation.   | STRING     | Any string   |
+-------------+----------------------------------------------+------------+--------------+

- **NotOneOf**
  -  Match when the specified field does not have a value from the given list.

+-------------+---------------------------------------------+------------+---------------------+
| **Field**   | **Description**                             | **Type**   | **Notes**           |
+=============+=============================================+============+=====================+
| field       | The field to test. Supports ${} notation.   | STRING     | Any string          |
+-------------+---------------------------------------------+------------+---------------------+
| values      | The matching values.                        | LIST       | A list of strings   |
+-------------+---------------------------------------------+------------+---------------------+

- **OneOf**
  -  Match when the specified field has a value from the given list.

+-------------+---------------------------------------------+------------+---------------------+
| **Field**   | **Description**                             | **Type**   | **Notes**           |
+=============+=============================================+============+=====================+
| field       | The field to test. Supports ${} notation.   | STRING     | Any string          |
+-------------+---------------------------------------------+------------+---------------------+
| values      | The matching values.                        | LIST       | A list of strings   |
+-------------+---------------------------------------------+------------+---------------------+

- **Or**
   - Create a set of filters. This filter matches when any one of them
     matches.

+-------------+--------------------+------------+---------------------+
| **Field**   | **Description**    | **Type**   | **Notes**           |
+=============+====================+============+=====================+
| filters     | Combined Filters   | LIST       | A list of filters   |
+-------------+--------------------+------------+---------------------+

- **RegEx**
   - Choose a field from the event to match against the regular expression
     you provide.

+-------------+---------------------------------------------------------+------------+--------------+
| **Field**   | **Description**                                         | **Type**   | **Notes**    |
+=============+=========================================================+============+==============+
| field       | The text to check for a match. Supports ${} notation.   | STRING     | Any string   |
+-------------+---------------------------------------------------------+------------+--------------+
| value       | The regular expression (pattern) to match.              | STRING     | Any string   |
+-------------+---------------------------------------------------------+------------+--------------+

- **StartsWith**
  - Check if a search string starts with another string.

+-------------+---------------------------------------------------+------------+--------------+
| **Field**   | **Description**                                   | **Type**   | **Notes**    |
+=============+===================================================+============+==============+
| string      | The value to search. Supports ${} notation.       | STRING     | Any string   |
+-------------+---------------------------------------------------+------------+--------------+
| Value       | The value to search for. Supports ${} notation.   | STRING     | Any string   |
+-------------+---------------------------------------------------+------------+--------------+

- **Unassigned**
   - Choose a field from the event to check for assignment. This filter
     matches when the field is not assigned.

+-------------------+--------------------------------------------------------+------------+-----------------+
| **Field**         | **Description**                                        | **Type**   | **Notes**       |
+===================+========================================================+============+=================+
| field             | The field to check for on the event.                   | STRING     | A field name    |
+-------------------+--------------------------------------------------------+------------+-----------------+
| emptyIsAssigned   | If true, an empty value is considered an assignment.   | BOOLEAN    | True or False   |
+-------------------+--------------------------------------------------------+------------+-----------------+

- **WithinSecondsFrom**
  - This filter matches when the specified epoch time value is within the
  given number of seconds from the baseline time value. Both time values
  are assumed to be in seconds. If a value is in milliseconds, set
  baselineTimeInMillis and/or eventTimeInMillis to true.

+------------------------+------------------------------------------------------------+------------+-----------------+
| **Field**              | **Description**                                            | **Type**   | **Notes**       |
+========================+============================================================+============+=================+
| field                  | The time value to test. Supports ${}                       | STRING     | A field name    |
+------------------------+------------------------------------------------------------+------------+-----------------+
| eventTimeInMillis      | Whether to convert the event value from milliseconds.      | BOOLEAN    | True or False   |
+------------------------+------------------------------------------------------------+------------+-----------------+
| seconds                | The number of seconds.                                     | NUMBER     | A number        |
+------------------------+------------------------------------------------------------+------------+-----------------+
| baselineTimeInMillis   | Whether to convert the baseline value from milliseconds.   | BOOLEAN    | True or False   |
+------------------------+------------------------------------------------------------+------------+-----------------+
| baseline               | The baseline time value. Supports ${}.                     | STRING     | Any string      |
+------------------------+------------------------------------------------------------+------------+-----------------+

- **WithinTimeFromNow**
  - This filter matches when the named field has an epoch time value
  within the given number of seconds from the current time. The event's
  time value is assumed to be in seconds. If it's in milliseconds, set
  eventTimeInMillis to true.

+---------------------+---------------------------------------------------------+------------+-----------------+
| **Field**           | **Description**                                         | **Type**   | **Notes**       |
+=====================+=========================================================+============+=================+
| field               | The field to check on the event.                        | STRING     | A field name    |
+---------------------+---------------------------------------------------------+------------+-----------------+
| eventTimeInMillis   | Whether to convert the event value from milliseconds.   | BOOLEAN    | True or False   |
+---------------------+---------------------------------------------------------+------------+-----------------+
| seconds             | The number of seconds.                                  | NUMBER     | A number        |
+---------------------+---------------------------------------------------------+------------+-----------------+

- **Limit:**

  -  Limit is the integer value and DMaaP Message Router will consumes
     only that set of message which are specified in limit.

  .. code:: bash

        Suppose if we set limit=2, then only 2 sets of data will be consumed.
        *Get \ **<<topicName>>/group/2?limit=4***
        Let us suppose if
        **No of data available** = 4
        **Set limit** = 6
        i.e. limit>no of data
        In this scenario all 4 sets of data will be consumed.

-  If limit is not passed with the url then by default limit is set to
   4096.

   .. code:: bash

        i.e. 4096 sets of data will be consumed.
        **Timeout and Long Poll:**

-  Timeout is the integer value which will be treated by DMaaP Message
   Router as time in millisecond.



-  Get

+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| `***http://localhost/DMaaP/dmaaprest/events/<<topicName>>/group/2?timeout=20000*** <http://localhost/DMaaP/dmaaprest/events/%3c%3ctopicName%3e%3e/group/2?timeout=20000>`__   |
+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

-  If there is no data available to be consumed, then DMaaP Message
   Router will poll for the particular period of time specified in
   timeout this mechanism is known as Long Poll.

-  If timeout is not passed with url then DMaaP Message Router will set
   the value of timeout =10000

-  i.e. if no set of data are available then DMaaP Message Router will
   poll for 10000 ms.

***Meta:***

-  Meta is a Boolean value.

-  DMaaP Message Router reads the value of meta from
   MRConfiguration.properties file at the time of startup.

-  If the value of meta is not null and if value of meta is one of these
   values true, yes, on, 1, y, checked then DMaaP Message Router will
   take meta flag as true, else it will be false.

-  If meta is set to true then consumer will get the value of message
   offset along with message.

   |image1|

   .. |image1| image:: images/image1.png

- **Pretty**:

-  Pretty is a Boolean value.

-  DMaaP Message Router reads the value of pretty from
   MRConfiguration.properties file at the time of startup.

-  If the value of pretty is not null and if value of pretty is one of
   these values true, yes, on, 1, y, checked then DMaaP Message Router
   will take pretty flag as true, else it will be false.

-  If pretty is set to true then different sets of messages will be
   printed in next line separated by comma (,).

   |image2|

   .. |image2| image:: images/image2.png

- **Filter**

   - A filter examine an event and decides if it matches or doesn't.
   - Filters are mainly used in rules to decide if the processing entries
     should be executed on the given event. They're also used for settings,
     and systems like the Graph Correlator re-use Highland Park's filter
     mechanism to specify which alarms fit in a correlation.
   - The standard library includes a number of simple filters. The Equals
     filter, for example, compares a field's value with some other value
     and returns true if the values match.
   - The standard library also includes filter classes called And, Or, and
     Not, so you can compose more complex filters. For example, written in
     the standard JSON config format:

    +-----------------------------------------+
    | "filter":{                              |
    | "class":"And",                          |
    | "filters":                              |
    | [                                       |
    | { "class":"Equals", "foo":"abc" },      |
    | { "class":"Assigned", "field":"bar" }   |
    | ]                                       |
    | }                                       |
    +-----------------------------------------+

   - This filter matches events in which the field "foo" has value "abc" and
     the field "bar" is assigned to some value (as opposed to not being
     present on the event).
   - Filters are used by the consumers to filter out data and consume only
     specific set of data which matches the conditions mentioned in filter.
   - Filters can be passed as a query parameter by the consumer in consume
     request as mentioned below:
     - **http://localhost:8080/DMaaP/dmaaprest/events/DMaaP/consumergroup/mHOeNFY4XiWx4CBa?filter=\\{"class":"Equals","field":"email", "value":"`test@abc.com <mailto:test@att.com>`__" }**
     - Filters can be applied only on data in JSON format i.e. if applied, filters will automatically ignore any non-json data.
     - While consuming, request CONTENT\_TYPE is not relevant to filter.

   The MR API allows a subscriber pass a Highland Park filter as part of
   the GET request. This will filter the stream of messages sent back to
   the subscriber, but for this to work, there are some requirements:

   -  The message payload must be JSON

   -  Only a filter built from Highland Park's Standard Library  may be
      used. (The Cambria API server doesn't have access to plugged in
      filters.)

   -  The filter must be encoded properly in the URL path.

Server-side filtering can also be setup in the Java client as illustrated below

**Filtering Consumer**

You can also provide a Highland Park filter to your consumer instance,
and this filter is passed on to the server in the GET request. One way
to create the filter is programmatically. In your code, instantiate a
filter from the Highland Park Standard Library Then create a String
representation of the filter using the FilterIo.write utility. This
String can then be passed to the Cambria client instance for use on the
server.

Remember, only Highland Park standard library filter components can be
used -- no plug-ins are available in the Cambria server context.

  .. code:: bash

  package org.onap.sa.highlandPark.integration;

  import java.io.IOException;

  import java.util.UUID;

  import org.onap.nsa.cambria.client.CambriaClientFactory;

  import org.onap.nsa.cambria.client.CambriaConsumer;

  import org.onap.sa.highlandPark.processor.HpEvent;

  import org.onap.sa.highlandPark.stdlib.filters.FilterIo;

  import org.onap.sa.highlandPark.stdlib.filters.OneOf;

  public class ExampleFilteringConsumer

  {

  public static void main ( String[] args ) throws IOException,
  InterruptedException

  {

  // Cambria clients take a set of 1 or more servers to use in round-robin
  fashion.

  // If a server becomes unreachable, another in the group is used.

  final String
  serverGroup="ueb01hydc.it.att.com,ueb02hydc.it.att.com,ueb03hydc.it.att.com";

  // choose a topic

  final String topic = "TEST-TOPIC";

  // Cambria clients can run in a cooperative group to handle high-volume
  topics.

  // Here, we create a random group name, which means this client is not
  re-startable.

  final String consumerGroup = UUID.randomUUID ().toString ();

  final String consumerId = "0";

  // Cambria clients can sit in a tight loop on the client side, using a
  long-poll

  // to wait for messages, and a limit to tell the server the most to send
  at a time.

  final int longPollMs = 30\*1000;

  final int limit = -1;

  // The Cambria server can filter the returned message stream using
  filters from the

  // Highland Park system. Here, we create a simple filter to test for the
  AlarmID

  // value being one of the Mobility power alarms.

  final OneOf oneOf = new OneOf ( "AlarmId", kPowerAlarms );

  // create the consumer

  final CambriaConsumer cc = CambriaClientFactory.createConsumer (
  serverGroup, topic,

  consumerGroup, consumerId, longPollMs, limit, FilterIo.write ( oneOf )
  );

  // now loop reading messages. Note that cc.fetch() will wait in its HTTP
  receive

  // method for up to 30 seconds (longPollMs) when nothing's available at
  the server.

  long count = 0;

  while ( true )

  {

  for ( String msg : cc.fetch () )

  {

  System.out.println ( "" + (++count) + ": " + msg );

  }

  }

  }

  private static final String[] kPowerAlarms =

  {

  "HUB COMMERCIAL POWER FAIL\_FWD",

  "HUB COMMERCIAL POWER FAIL",

  "RBS COMMERCIAL POWER FAIL - Fixed\_FWD",

  "RBS COMMERCIAL POWER FAIL\_FWD",

  "RBS COMMERCIAL POWER FAIL - No Generator\_FWD",

  "RBS COMMERCIAL POWER FAIL - Portable\_FWD",

  "RBS COMMERCIAL POWER FAIL - Shared\_FWD",

  "RBS COMMERCIAL POWER FAIL - Yes\_FWD",

  "RBS COMMERCIAL POWER FAIL - YES\_FWD",

  "RBS COMMERCIAL POWER FAIL - Fixed",

  "RBS COMMERCIAL POWER FAIL - No Generator",

  "RBS COMMERCIAL POWER FAIL - Portable",

  "RBS COMMERCIAL POWER FAIL - Shared",

  "RBS COMMERCIAL POWER FAIL - YES",

  "RBS COMMERCIAL POWER FAIL - Yes",

  "RBS COMMERCIAL POWER FAIL",

  "HUB COMMERCIAL POWER FAIL - Fixed",

  "HUB COMMERCIAL POWER FAIL - No Generator",

  "HUB COMMERCIAL POWER FAIL - Portable",

  "HUB COMMERCIAL POWER FAIL - Shared",

  "HUB COMMERCIAL POWER FAIL - Fixed\_FWD",

  "HUB COMMERCIAL POWER FAIL - No Generator\_FWD",

  "HUB COMMERCIAL POWER FAIL - Portable\_FWD",

  "HUB COMMERCIAL POWER FAIL - Shared\_FWD",

  };

  }



**Filter Builder**

 MR server-side filtering allows a consumer to filter the stream of
 messages returned from the GET call.  The following link provide details
 of building some of the filter to illustrate Filter Builder.  It is not
 meant to cover and provide examples of every filter