New max_message_size property to limit output datagrams size (#770) (…

…#774) * Refs #20849: Add max_message_size property policy docs Signed-off-by: elianalf <62831776+elianalf@users.noreply.github.com> * Refs 20849: Apply suggestions Signed-off-by: elianalf <62831776+elianalf@users.noreply.github.com> * Refs #20849: Apply suggestions Signed-off-by: elianalf <62831776+elianalf@users.noreply.github.com> --------- Signed-off-by: elianalf <62831776+elianalf@users.noreply.github.com> (cherry picked from commit 91d96b8) # Conflicts: # code/DDSCodeTester.cpp Co-authored-by: elianalf <62831776+elianalf@users.noreply.github.com>
eProsima · May 23, 2024 · e284e8b · e284e8b
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diff --git a/code/DDSCodeTester.cpp b/code/DDSCodeTester.cpp
@@ -883,6 +883,28 @@ void dds_domain_examples()
             "unicast");
         //!--
     }
+
+    {
+        // 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");
+        //!--
+    }
 }
 
 //DOMAINPARTICIPANTLISTENER-DISCOVERY-CALLBACKS

diff --git a/code/XMLTester.xml b/code/XMLTester.xml
@@ -3229,6 +3229,42 @@
 -->
 <!--><-->
 
+<!-->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>

diff --git a/docs/fastdds/property_policies/non_consolidated_qos.rst b/docs/fastdds/property_policies/non_consolidated_qos.rst
@@ -351,3 +351,82 @@ The behavior regarding this can be configured using the property ``fastdds.shm.e
            :language: xml
            :start-after: <!-->XML-SHM-ENFORCE-META-TRAFFIC
            :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