dgochenour / dds_pro_labs_c

QuickStart training hands-on exercises (C version)

QuickStart Hands-On Exercises

This repo contains labs used in DDS QuickStart training, C version. Before any given lab can be compiled and run, rtiddsgen should be run on the *.idl file in each directory. When performing this step, be sure to set the following:

• Generation: Example Files = ""
• Generation: Type files = "update"
• Generation: Makefiles = "create"
• Language = "C"

Lab 1. Out Of The Box

• Create IDL, then generate code, build and run
• Decrease the DataWriter wait time from 4s to 2s
• Give the sample members some values, just so we aren't writing empty data
• In the QoS XML, update publication_name and subscription_name with meaningful values (student names, etc.)

Lab 2. Deadline Qos

• Set deadline to 1.0 sec. on DataReader
• Discuss why not working. (QoS mismatch)
• Fix Reader listener to note Qos Error
  • In the C (or C++98) documentation, search for DDS_QosPolicyId_t; here you can match "4" to "DDS_DEADLINE_QOS_POLICY_ID"
• Fix Writer to offer Deadline of 500ms

Lab 3. Time Based Filter

• Speed up writer to 10HZ.
• Note that Reader is getting swamped.
• Set Reader Time Based Filter Minimum separation to 1.0 sec (in Qos XML) and extend deadline to 1.5 Sec.
• Note any possible Syncopation and discuss that.

Lab 4. Keys and defining constants in the IDL.

• Update IDL to add //@key and set unique key value per student
• Also, add a constant string to the IDL for topic name and make changes in pub & sub to use this string.
• Restart pubs and subs and discuss output.

Lab 5. Ownership and fail rollover.

• In QoS XML, set EXCLUSIVE_OWNERSHIP_QOS on both Reader and writer.
• Set Strength to unique value for each student. (assuming unique key values from last lab)
• Note Results.
• Now have students all use the same key value (all writing to the same instance)
• Start running from lowest strength to highest strength.
• Kill apps from Highest to lowest strength.

NOTE 1: (If everyone is not connected to the same network, demonstrate Ownership using Shapes Demo on a single machine)

NOTE 2: subscribe to the data with Admin Console, demonstrating how to override the ownership settings

Lab 6. Loading a user-defined XML QoS profile

• Copy USER_QOS_PROFILES.xml to a new file called MY_QOS_PROFILES.xml
• rename the library to "MyLibrary" and profile to "MyProfile"
• remove is_default_qos="true" from MyProfile
• change DW and DR back to SHARED_OWNERSHIP_QOS
• change publisher and subscriber code to use custom qosProvider

Lab 7. Listeners and Waitsets

• Modify the subscriber code so that the read is done via a waitset instead of the default listener
• Point out the changes made in the declarations, as well as how the main loop is refactored
• Note that the waitset is actually a better approach in terms of not blocking the DDS threads

Lab 8. Reliability.

• remove base_name="BuiltinQosLibExp::Generic.StrictReliable" from QoS
• remove TBF and deadline QoS from DW and DR (just to clean things up)
• Set reliability to RELIABLE_RELIABILITY_QOS in Reader.
• Slow down writer to 1HZ.
• Discuss that the data is now coming in at 1Hz
• Now set writer to wait for reliable acknowledgements.
• Discuss writer write speed.
• Set up writer protocol to correct.

Lab 9. Late Joiner History.

• Set Writer and Reader Durability to TRANSIENT_LOCAL_DURABILITY_QOS.
• Set History to KEEP_LAST_HISTORY_QOS, depth 10. Vary by students.
• Set Reader History to depth 15.
• Add monitoring library support
  • wait for errors from statically linked libs, discuss, then fix that in the makefile
  • NOTE: make sure there isn't any whitespace after the "SHAREDLIB=1" as this will cause problems
• Start Writer then Reader apps one at a time and discuss late joiner results.

Lab 10. Content Filtered topic

• modify publisher to change the value of name on every other send
  • run pub and sub to verify that you are seeing the expected results
• Now modify subscriber code to add a cft
  • add code to create the parameters and Filter
  • set the filter name
  • change the reader instantiation to use ContentFilteredTopic instead of normal topic
• open admin console to show that no new topic is shown, the filtering is logical but does not spawn a new entity

dds_pro_labs_c's Issues

create 5.3.1 release branch

migrate all labs to 6.0.0