[20849] New max_message_size property to limit output datagrams size (backport #770)

code/DDSCodeTester.cpp

@@ -890,6 +890,28 @@ void dds_domain_examples()
  "fastdds.tcp_transport.non_blocking_send",
  "true");
  //!--
+ }
+
+ {
+ // MAX_MESSAGE_SIZE_PROPERTY_PARTICIPANT
+ DomainParticipantQos pqos;
+
+ // Set maximum number of bytes of the datagram to be sent
+ pqos.properties().properties().emplace_back(
+ "fastdds.max_message_size",
+ "1200");
+ //!--
+ }
+
+ {
+ // MAX_MESSAGE_SIZE_PROPERTY_WRITER
+ DataWriterQos wqos;
+
+ // Set maximum number of bytes of the datagram to be sent
+ wqos.properties().properties().emplace_back(
+ "fastdds.max_message_size",
+ "1200");
+ //!--
  }
 }
 

code/XMLTester.xml

@@ -3110,6 +3110,42 @@
 -->
 <!--><-->
 
+<!-->MAX_MESSAGE_SIZE_PROPERTY_PARTICIPANT<-->
+<!--
+<?xml version="1.0" encoding="UTF-8" ?>
+-->
+<participant profile_name="max_message_size_participant_xml_profile">
+ <rtps>
+ <propertiesPolicy>
+ <properties>
+ <!-- Set the maximum size in bytes for all RTPS datagrams sent by the participant -->
+ <property>
+ <name>fastdds.max_message_size</name>
+ <value>1200</value>
+ </property>
+ </properties>
+ </propertiesPolicy>
+ </rtps>
+</participant>
+<!--><-->
+
+<!-->MAX_MESSAGE_SIZE_PROPERTY_WRITER<-->
+<!--
+<?xml version="1.0" encoding="UTF-8" ?>
+-->
+<data_writer profile_name="max_msg_size_datawriter_xml_profile">
+ <propertiesPolicy>
+ <properties>
+ <!-- Set the maximum size in bytes for all RTPS datagrams sent by the writer -->
+ <property>
+ <name>fastdds.max_message_size</name>
+ <value>1200</value>
+ </property>
+ </properties>
+ </propertiesPolicy>
+</data_writer>
+<!--><-->
+
 <!-->FASTDDS_STATISTICS_MODULE<-->
 <participant profile_name="statistics_domainparticipant_conf_xml_profile">
  <rtps>

docs/fastdds/property_policies/non_consolidated_qos.rst

@@ -395,3 +395,82 @@ packet.
  :language: xml
  :start-after: <!-->XML-TCP-NON-BLOCKING-SEND
  :end-before: <!--><-->
+
+.. _property_max_message_size:
+
+Maximum Message Size
+^^^^^^^^^^^^^^^^^^^^
+
+One common requirement is the differentiation between the maximum size of received and sent datagrams.
+This capability is especially important in scenarios where a system might need to handle large incoming
+data sizes but should restrict the size of the data it sends to prevent overwhelming network resources
+or complying with network traffic policies.
+The primary attribute for controlling datagram size is `maxMessageSize`, which sets the upper limit
+for both the size of datagrams that can be received and those that can be sent.
+Property ``fastdds.max_message_size`` allows restricting the size of outgoing datagrams without
+changing the size of incoming ones.
+This property allows for the specific configuration of the maximum number of bytes for datagrams that
+are sent.
+By configuring this property to a value lower than the smallest `maxMessageSize` across all transports,
+applications can achieve a lower sending limit while maintaining the ability to receive larger datagrams.
+
+.. list-table::
+ :header-rows: 1
+ :align: left
+
+ * - PropertyPolicyQos name
+ - PropertyPolicyQos value
+ - Default value
+ * - ``"fastdds.max_message_size"``
+ - ``uint32_t``
+ - ``"4294967295"``
+
+.. note::
+ An invalid value of ``fastdds.max_message_size`` would log an error,
+ and the default value will be used.
+
+.. _setting_max_message_size_participant:
+
+Setting ``fastdds.max_message_size`` At Participant Level
+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+.. tabs::
+
+ .. tab:: C++
+
+ .. literalinclude:: /../code/DDSCodeTester.cpp
+ :language: c++
+ :start-after: // MAX_MESSAGE_SIZE_PROPERTY_PARTICIPANT
+ :end-before: //!--
+ :dedent: 6
+
+ .. tab:: XML
+
+ .. literalinclude:: /../code/XMLTester.xml
+ :language: xml
+ :start-after: <!-->MAX_MESSAGE_SIZE_PROPERTY_PARTICIPANT<-->
+ :end-before: <!--><-->
+ :lines: 2,4-16
+
+.. _setting_max_message_size_writer:
+
+Setting ``fastdds.max_message_size`` At Writer Level
+""""""""""""""""""""""""""""""""""""""""""""""""""""
+
+.. tabs::
+
+ .. tab:: C++
+
+ .. literalinclude:: /../code/DDSCodeTester.cpp
+ :language: c++
+ :start-after: // MAX_MESSAGE_SIZE_PROPERTY_WRITER
+ :end-before: //!--
+ :dedent: 6
+
+ .. tab:: XML
+
+ .. literalinclude:: /../code/XMLTester.xml
+ :language: xml
+ :start-after: <!-->MAX_MESSAGE_SIZE_PROPERTY_WRITER<-->
+ :end-before: <!--><-->
+ :lines: 2,4-14