hdds-discovery-dump

Dump live DDS discovery state - see participants, topics, readers, and writers on your network.

Overview

hdds-discovery-dump joins a DDS domain and displays the discovery state after collecting announcements. It shows all discovered participants with their endpoints, and all topics with their associated writers and readers.

Installation

From Source

cd hdds/tools/hdds-discovery-dump
cargo build --release

Binary at target/release/hdds-discovery-dump.

From Cargo

cargo install hdds-discovery-dump

Usage

hdds-discovery-dump [OPTIONS]

Options:
  -d, --domain <DOMAIN>    DDS domain ID [default: 0]
      --timeout <TIMEOUT>  Discovery duration in seconds [default: 5]
  -f, --format <FORMAT>    Output format: pretty, json [default: pretty]
  -w, --watch <WATCH>      Continuous monitoring mode (refresh every N seconds)
  -t, --topic <TOPIC>      Filter by topic name
      --quiet              Compact output
  -h, --help               Print help
  -V, --version            Print version

Examples

Basic Discovery Dump

hdds-discovery-dump

Output:

>>> Discovery dump (domain=0)
    Discovering for 5 seconds...

=== DDS Discovery State ===

Participants: 3 participant(s) discovered

  [1] 01aa0001.c0a80064.00000001.000001c1
      State: Alive
      Endpoints: 7400, 7401
      Lease: 10000ms (expires in 8523ms)

  [2] 010f0001.c0a80065.00000002.000001c1
      State: Alive
      Endpoints: 7400, 7401
      Lease: 15000ms (expires in 12100ms)

Topics: 2 topic(s)

  Topic: temperature
      Writers: 1  Readers: 2
        W 01aa0001.c0a80064.00000001.00000102 (type: Temperature)
        R 010f0001.c0a80065.00000002.00000107 (type: Temperature)
        R 01aa0001.c0a80064.00000003.00000107 (type: Temperature)

  Topic: sensor_data
      Writers: 2  Readers: 1
        W 01aa0001.c0a80064.00000001.00000202 (type: SensorReading)
        W 010f0001.c0a80065.00000002.00000202 (type: SensorReading)
        R 01aa0001.c0a80064.00000003.00000207 (type: SensorReading)

--- Summary ---
  Participants: 3  Topics: 2  Writers: 3  Readers: 3

Different Domain

hdds-discovery-dump -d 42

Longer Discovery Time

For networks with slow discovery or many participants:

hdds-discovery-dump --timeout 15

JSON Output

hdds-discovery-dump --format json

Output:

{"domain":0,"participants":[{"guid":"01aa0001.c0a80064.00000001.000001c1","state":"Alive","endpoints":["7400","7401"],"lease_ms":10000}],"topics":[{"name":"temperature","writers":[{"guid":"01aa0001.c0a80064.00000001.00000102","type":"Temperature"}],"readers":[{"guid":"01aa0001.c0a80064.00000003.00000107","type":"Temperature"}]}]}

Pretty-print with jq:

hdds-discovery-dump -f json | jq .

Watch Mode (Continuous Monitoring)

Refresh every 2 seconds:

hdds-discovery-dump -w 2

The screen clears and updates with fresh discovery state. Press Ctrl+C to stop.

Filter by Topic

Only show topics matching a pattern:

hdds-discovery-dump -t temperature
hdds-discovery-dump -t sensor

Quiet Mode

Compact single-line output per item:

hdds-discovery-dump --quiet

Output:

  [1] 01aa0001.c0a80064.00000001.000001c1 (Alive) 7400, 7401
  [2] 010f0001.c0a80065.00000002.000001c1 (Alive) 7400, 7401
  temperature (1W/2R)
  sensor_data (2W/1R)

Combine Options

Watch a specific topic in quiet mode:

hdds-discovery-dump -w 1 -t chatter --quiet

Output Details

Participant Information

Field	Description
GUID	16-byte globally unique identifier (format: prefix.prefix.prefix.entityId)
State	Alive or Stale (lease expired)
Endpoints	Locator ports (multicast/unicast)
Lease	Remaining time before participant is considered dead

Topic Information

Field	Description
Name	Topic name string
Writers	Count and list of DataWriters
Readers	Count and list of DataReaders
Type	Data type name for each endpoint

Vendor Identification

GUID prefixes identify vendors:

• 01aa.... - HDDS
• 010f.... - FastDDS (eProsima)
• 0101.... - RTI Connext
• 0110.... - CycloneDDS
• 0103.... - OpenDDS

Use Cases

Network Debugging

Check if publishers and subscribers have discovered each other:

hdds-discovery-dump -t my_topic

If writers exist but no readers (or vice versa), there's a discovery or QoS mismatch.

Cross-Vendor Interop Testing

Verify participants from different DDS vendors can see each other:

hdds-discovery-dump --timeout 10 -f json | jq '.participants[].guid'

Continuous Monitoring Dashboard

Run in watch mode to monitor a live system:

hdds-discovery-dump -w 5

Scripted Health Checks

# Check if any participants exist
count=$(hdds-discovery-dump --timeout 3 -f json | jq '.participants | length')
if [ "$count" -eq 0 ]; then
  echo "No DDS participants found!"
  exit 1
fi

Export Discovery State

hdds-discovery-dump -f json > discovery_$(date +%Y%m%d_%H%M%S).json

Comparison with Other Tools

Feature	hdds-discovery-dump	RTI Admin Console	FastDDS Monitor
CLI-based	Yes	No (GUI)	No (GUI)
JSON export	Built-in	XML	JSON
Cross-vendor	Yes	RTI only	FastDDS only
Watch mode	Yes	Yes	Yes
Topic filter	Yes	Yes	Yes
Lightweight	~2MB	~500MB	~100MB

Troubleshooting

No Participants Found

1. Check domain ID matches other participants
2. Verify multicast is enabled on your network
3. Increase timeout: --timeout 15
4. Check firewall allows UDP ports 7400-7500

Discovery Not Available

If you see "Discovery not available (intra-process mode?)":

• The participant was created with IntraProcess transport only
• Switch to UdpMulticast transport to enable network discovery

Stale Participants

Participants showing State: Stale have missed their lease renewal:

• The remote process may have crashed
• Network connectivity issues
• Lease duration too short for network latency

Exit Codes

Code	Meaning
0	Success
1	Error (DDS initialization failed, etc.)