7.2. Resources

Monitoring Library 2.0 collects telemetry data associated with observable resources. In this release, the observable resources are:

Application (one-to-one mapping to an OS process)
DomainParticipant
Topic
Publisher
Subscriber
DataWriter
DataReader

Each observable resource is identified by a GUID and a resource name. The GUID is automatically assigned by Monitoring Library 2.0, and it is globally unique across all the resources in the system (past and present). The resource GUID can be accessed using the guid label associated with each metric. The fully qualified resource name for each observable resource is represented by a Uniform Resource Identifier (URI). The URI strings follow REST best practices for naming. Table 7.1 details of each available resource. See Metrics for detailed information about the metrics available for each observable resource in this release.

Table 7.1 Observable Resource Names
Resource	Uniform Resource Identifier (URI)	Dashboard Resource Name	How to Configure
Application	`/applications/<AppName>`	`<AppName>`	To set <AppName>, configure the `participant_factory_qos.monitoring.application_name` QoS policy field for an application. For more information, see MONITORING QosPolicy (DDS Extension)
DomainParticipant	`/applications/<AppName>/domain_participants/<ParticipantName>`	`<AppName>/<ParticipantName>`	To set <ParticipantName>, configure the `participant_qos.participant_name.name` QoS policy field for a DomainParticipant. For more information, see ENTITY NAME QosPolicy (DDS Extension)
Topic	`/applications/<AppName>/domain_participants/<ParticipantName>/topics/<TopicName>`	`<TopicName>`	<TopicName> is the name of the DDS Topic. This resource cannot be configured in the Monitoring QoS.
Publisher	`/applications/<AppName>/domain_participants/<ParticipantName>/publishers/<PublisherName>`	Dashboards do not show information about Publishers	To set <PublisherName>, configure the `publisher_qos.publisher_name.name` QoS policy field for a Publisher. For more information, see ENTITY NAME QosPolicy (DDS Extension)
Subscriber	`/applications/<AppName>/domain_participants/<ParticipantName>/subscribers/<SubscriberName>`	Dashboards do not show information about Subscribers	To set <SubscriberName>, configure the `publisher_qos.subscriber_name.name` QoS policy field for a Subscriber. For more information, see ENTITY NAME QosPolicy (DDS Extension)
DataWriter	`/applications/<AppName>/domain_participants/<ParticipantName>/publishers/<PublisherName>/data_writers/<DataWriterName>`	`<AppName>/<ParticipantName>/<DataWriterName>`	To set <DataWriterName>, configure the `writer_qos.publication_name.name` QoS policy field for a DataWriter. For more information, see ENTITY NAME QosPolicy (DDS Extension)
DataReader	`/applications/<AppName>/domain_participants/<ParticipantName>/publishers/<PublisherName>/data_readers/<DataReaderName>`	`<AppName>/<ParticipantName>/<DataReaderName>`	To set <DataReaderName>, configure the `reader_qos.subscription_name.name` QoS policy field for a DataReader. For more information, see ENTITY NAME QosPolicy (DDS Extension)

The Dashboard Resource Name column describes how resource names appear in RTI Connext Observability Dashboards. To generate shorter names, Observability Dashboards does not show the resource class name (e.g, domain_participants).

Important

Observability Framework does not enforce unique resource names. You are responsible for assigning unique names. When two observable resources have the same name, the commands targeting the resource name are applied to both resources. For example, if two applications have the same name and you change the logging verbosity from Observability Dashboards, the change will apply to both applications. Otherwise, not having unique names should not affect functionality because each resource has a unique GUID.

7.2.1. Resource Pattern Definitions

There are two ways to configure telemetry data collection and forwarding. These are the initial configuration of the Monitoring Library 2.0 (see Monitoring Library 2.0) and use of the REST API to dynamically configure the collection of telemetry data (see Collector Service REST API Reference) for distribution. In both cases, the Uniform Resource Identifiers (URIs) shown in Table 7.1 are used to identify the observable resources being configured by the XML or REST API. Resource selectors are used in the XML file configuration and in REST API commands to provide a pattern string to match one or more URIs.

A resource selector is an expression made up of components, with each component separated by a forward slash (/). A component is a pattern string that follows the POSIX® fnmatch syntax, or a resource GUID. In addition, you can use XPath-style matching (//) to change the path level by 0 or more components until finding a component matching the pattern following (//).

When specifying resource selectors, POSIX fnmatch pattern matching can be used. The available POSIX® fnmatch special characters are described in Table 7.2.

Table 7.2 POSIX® fnmatch Wild Card Matching
Character	Meaning
`/`	A `/` in the pattern string matches a `/` in the URI. It separates a sequence of mandatory substrings.
`*`	A `*` in the pattern string matches 0 or more non-special characters in the URI.
`?`	A `?` in the pattern string matches any single non-special characters in the URI.
`[charlist]`	Matches any one of the characters in charlist.
`[s-e]`	Matches any character from [s]tart to [e]nd, inclusive.
`\`	Escape character for special characters.

Note: To use special characters in a resource selector string, you must escape them using a back slash (\). For example, the resource selector “myWriter[2]” will match a DataWriter with name “myWriter2” because of the POSIX® fnmatch processing. If the intent is to use the ‘[’ and ‘]’ characters in the resource selector to actually match a name, the ‘[’ and ‘]’ characters must be escaped as shown here “myWriter\[2\]”. This resource selector would match a DataWriter with the name “myWriter[2]”. Some example resource selectors using POSIX® fnmatch are shown below.

Table 7.3 POSIX® fnmatch Resource Selector Examples
Resource Selector	Description
/applications/SensorPublisher_1	refers to an application named “SensorPublisher_1”
/applications/SensorPublisher_?	refers to applications named “SensorPublisher_” with a single additional character (i.e. “SensorPublisher_1”, “SensorPublisher_2”, “SensorPublisher_a”)
/app/SensorPublisher_	refers to applications named “SensorPublisher_” with any number of additional characters, including none (i.e. “SensorPublisher_”, “SensorPublisher_1”, “SensorPublisher_10”, “SensorPublisher_xyz”)
/applications/SensorPublisher_1/domain_participants//publishers//data_writers/Sensor with ID = [12]	refers to data_writers of application “SensorPublisher_1” named “Sensor with ID = 1” or “Sensor with ID = 2”
/applications/SensorPublisher_1/domain_participants//publishers//data_writers/Sensor with ID = [1-3]	refers to data_writers of application “SensorPublisher_1” named “Sensor with ID = 1”, “Sensor with ID = 2”, or “Sensor with ID = 3”

In addition to POSIX® fnmatch pattern matching, resource selectors also support the XPath (//). The (//) is essentially a relative path indicator that looks for the first occurrence of the text following the (//) in the resource selector. Think of the (//) as a global (*) to match any pattern before the specified text. Use of the XPath (//) can significantly shorten resource selectors. Some example resource selectors using XPath (//) and POSIX® fnmatch are shown below.

Table 7.4 XPath ‘//’ and POSIX® fnmatch Resource Selector Examples
Resource Selector	Description
/applications/SensorPublisher_1//data_writers/Sensor with ID = [12]	refers to data_writers of application “SensorPublisher_1” named “Sensor with ID = 1” or “Sensor with ID = 2”
//data_writers/Sensor with ID = [1-3]	refers to any data_writers named “Sensor with ID = 1”, “Sensor with ID = 2”, or “Sensor with ID = 3”
//TemperatureDataReader	refers to any DDS entities with the name “TemperatureDataReader”

As mentioned earlier, each DDS entity is assigned a unique identifier or GUID. When creating resource selectors, an entity GUID and entity name are interchangeable. When using a GUID in a resource selector, the format is GUID(<guid>). Some example resource selectors are shown below.

Table 7.5 GUID Resource Selector Examples
Resource Selector	Description
/applications/GUID(aaaaaaaa.bbbbbbbb.cccccccc.dddddddd)//data_writers/Sensor with ID = [12]	refers to data_writers of application with GUID=aaaaaaaa.bbbbbbbb.cccccccc.dddddddd named “Sensor with ID = 1” or “Sensor with ID = 2”
//data_writers/GUID(bbbbbbbb.aaaaaaaa.cccccccc.dddddddd)	refers to the data_writer with GUID=bbbbbbbb.aaaaaaaa.cccccccc.dddddddd
//GUID(dddddddd.cccccccc.bbbbbbbb.aaaaaaaa)	refers to the DDS resource with GUID=dddddddd.cccccccc.bbbbbbbb.aaaaaaaa regardless of the class

Note that the POSIX® fnmatch syntax may not be applied to the GUID(<guid>) format.