1.7. Get entity meta information

Fast DDS Statistics Backend includes the possibility of retrieving the meta information of any given entity present in the network. The returned tree always includes the basic information about the entity: kind, id, name, alias and if the entity is alive. Depending on the EntityKind, the returned object can contain extra information such as pid, guid, qos, locators or data_type. get_info() returns a Info object.

Info host_info = StatisticsBackend::get_info(host_id);
Info user_info = StatisticsBackend::get_info(user_id);
Info process_info = StatisticsBackend::get_info(process_id);
Info locator_info = StatisticsBackend::get_info(locator_id);
Info domain_info = StatisticsBackend::get_info(domain_id);
Info participant_info = StatisticsBackend::get_info(participant_id);
Info datareader_info = StatisticsBackend::get_info(datareader_id);
Info datawriter_info = StatisticsBackend::get_info(datawriter_id);
Info topic_info = StatisticsBackend::get_info(topic_id);

1.7.1. Host Info example

{
    "id": 1,
    "kind": "host",
    "name": "host_name",
    "alias": "host_alias",
    "alive": true
}

1.7.2. User Info example

{
    "id": 2,
    "kind": "user",
    "name": "user_name",
    "alias": "user_alias",
    "alive": true
}

1.7.3. Process Info example

{
    "id": 3,
    "kind": "process",
    "name": "process_name",
    "alias": "process_alias",
    "alive": true,
    "pid": "9564"
}

1.7.4. Locator Info example

{
    "id": 4,
    "kind": "locator",
    "name": "127.0.0.1:7412",
    "alias": "localhost",
    "alive": true
}

1.7.5. Domain Info example

{
    "id": 0,
    "kind": "domain",
    "name": "0",
    "alias": "domain_alias",
    "alive": true
}

1.7.6. Participant Info example

{
    "id": 5,
    "kind": "participant",
    "name": "participant_name",
    "alias": "participant_alias",
    "alive": true,
    "guid": "01.0f.22.cd.59.64.04.00.05.00.00.00|00.00.01.c1",
    "qos": {
        "available_builtin_endpoints": 3135,
        "lease_duration":
        {
            "nanoseconds": 0,
            "seconds": 3
        },
        "properties":
        [
            {
                "name": "PARTICIPANT_TYPE",
                "value": "CLIENT"
            },
            {
                "name": "DS_VERSION",
                "value": "2.0"
            }
        ],
        "user_data": "656e636c6176653d2f3b00",
        "vendor_id": "010f"
    },
    "locators":
    [
        "127.0.0.1:1234"
    ]
}

1.7.7. DataReader Info example

{
    "id": 6,
    "kind": "datareader",
    "name": "datareader_name",
    "alias": "datareader_alias",
    "alive": false,
    "guid": "01.0f.22.cd.59.64.04.00.05.00.00.00|00.00.01.04",
    "qos":
    {
        "data_sharing":
        {
            "domain_ids":
            [
                0
            ],
            "kind": "AUTO",
            "max_domains": 1,
            "shm_directory": "/dev/shm"
        },
        "deadline":
        {
            "period":
            {
                "nanoseconds": 50,
                "seconds": 10
            }
        },
        "destination_order":
        {
            "kind": "BY_RECEPTION_TIMESTAMP_DESTINATIONORDER_QOS"
        },
        "disable_positive_acks":
        {
            "duration":
            {
                "nanoseconds": 100,
                "seconds": 0
            },
            "enabled": true
        },
        "durability":
        {
            "kind": "VOLATILE_DURABILITY_QOS"
        },
        "durability_service":
        {
            "history_depth": 1,
            "history_kind": "KEEP_LAST_HISTORY_QOS",
            "max_instances": 30,
            "max_samples": 3000,
            "max_samples_per_instance": 100,
            "service_cleanup_delay":
            {
                "nanoseconds": 0,
                "seconds": 5
            }
        },
        "group_data": "9d46781410ff",
        "latency_budget":
        {
            "duration":
            {
                "nanoseconds": 50,
                "seconds": 10
            }
        },
        "lifespan":
        {
            "duration":
            {
                "nanoseconds": 0,
                "seconds": 10000
            }
        },
        "liveliness":
        {
            "announcement_period":
            {
                "nanoseconds": 0,
                "seconds": 3
            },
            "lease_duration":
            {
                "nanoseconds": 0,
                "seconds": 10
            },
            "kind": "AUTOMATIC_LIVELINESS_QOS"
        },
        "ownership":
        {
            "kind": "SHARED_OWNERSHIP_QOS"
        },
        "partition":
        [
            "partition_1",
            "partition_2"
        ],
        "presentation":
        {
            "access_scope": "INSTANCE_PRESENTATION_QOS",
            "coherent_access": false,
            "ordered_access": false
        },
        "reliability":
        {
            "kind": "RELIABLE_RELIABILITY_QOS",
            "max_blocking_time":
            {
                "nanoseconds": 0,
                "seconds": 3
            }
        },
        "representation":
        [
        ],
        "time_based_filter":
        {
            "minimum_separation":
            {
                "seconds": 12,
                "nanoseconds": 0
            }
        },
        "topic_data": "5b33419a",
        "type_consistency":
        {
            "force_type_validation": false,
            "ignore_member_names": false,
            "ignore_sequence_bounds": true,
            "ignore_string_bounds": true,
            "kind": "DISALLOW_TYPE_COERCION",
            "prevent_type_widening": false
        },
        "user_data": "ff00"
    }
}

1.7.8. DataWriter Info example

{
    "id": 7,
    "kind": "datawriter",
    "name": "datawriter_name",
    "alias": "datawriter_alias",
    "alive": true,
    "guid": "01.0f.22.cd.59.64.04.00.02.00.00.00|00.00.01.03",
    "qos":
    {
        "data_sharing":
        {
            "domain_ids":
            [
                0
            ],
            "kind": "AUTO",
            "max_domains": 1,
            "shm_directory": "/dev/shm"
        },
        "deadline":
        {
            "period":
            {
                "nanoseconds": 50,
                "seconds": 10
            }
        },
        "destination_order":
        {
            "kind": "BY_RECEPTION_TIMESTAMP_DESTINATIONORDER_QOS"
        },
        "disable_positive_acks":
        {
            "duration":
            {
                "nanoseconds": 100,
                "seconds": 0
            },
            "enabled": true
        },
        "durability":
        {
            "kind": "VOLATILE_DURABILITY_QOS"
        },
        "durability_service":
        {
            "history_depth": 1,
            "history_kind": "KEEP_LAST_HISTORY_QOS",
            "max_instances": 30,
            "max_samples": 3000,
            "max_samples_per_instance": 100,
            "service_cleanup_delay":
            {
                "nanoseconds": 0,
                "seconds": 5
            }
        },
        "group_data": "9d46781410ff",
        "latency_budget":
        {
            "duration":
            {
                "nanoseconds": 50,
                "seconds": 10
            }
        },
        "lifespan":
        {
            "duration":
            {
                "nanoseconds": 0,
                "seconds": 10000
            }
        },
        "liveliness":
        {
            "announcement_period":
            {
                "nanoseconds": 0,
                "seconds": 3
            },
            "lease_duration":
            {
                "nanoseconds": 0,
                "seconds": 10
            },
            "kind": "AUTOMATIC_LIVELINESS_QOS"
        },
        "ownership":
        {
            "kind": "SHARED_OWNERSHIP_QOS"
        },
        "ownership_strength":
        {
            "value": 5
        },
        "partition":
        [
            "partition_1",
            "partition_2"
        ],
        "presentation":
        {
            "access_scope": "INSTANCE_PRESENTATION_QOS",
            "coherent_access": false,
            "ordered_access": false
        },
        "publish_mode":
        {
            "kind": "ASYNCHRONOUS_PUBLISH_MODE"
        },
        "reliability":
        {
            "kind": "RELIABLE_RELIABILITY_QOS",
            "max_blocking_time":
            {
                "nanoseconds": 0,
                "seconds": 3
            }
        },
        "representation":
        [
        ],
        "time_based_filter":
        {
            "minimum_separation":
            {
                "seconds": 12,
                "nanoseconds": 0
            }
        },
        "topic_data": "5b33419a",
        "user_data": "ff00"
    }
}

1.7.9. Topic Info example

{
    "id": 8,
    "kind": "topic",
    "name": "topic_name",
    "alias": "topic_alias",
    "alive": true,
    "data_type": "example_data_type"
}