The example programs in the examples/ subdirectory are not built by default. To enable them, use the --with-examples configure option:

./waf configure --with-examples

Once built, the example binaries can be found under build/examples/:

  • Full sync: psync-full-sync

  • Partial sync: psync-producer and psync-consumer

If the library is installed to the system using ./waf install, then the examples will also be installed and can be executed directly.

Partial Sync Example

The partial sync example of PSync has two parts: producer and consumer. These can be run on a machine after starting NFD.


  • Enable logging for the producer.

    export NDN_LOG="examples.PartialSyncProducerApp=INFO"
  • Start the producer that will listen on /sync and publish one update for each of /a-0/a-9.

    psync-producer /sync /a 10 1
  • Sample output:

    1546280442.096296 INFO: [examples.PartialSyncProducerApp] Publish: /a-1/1
    1546280456.053138 INFO: [examples.PartialSyncProducerApp] Publish: /a-6/1
    1546280458.210415 INFO: [examples.PartialSyncProducerApp] Publish: /a-8/1
    1546280469.954134 INFO: [examples.PartialSyncProducerApp] Publish: /a-5/1
    1546280472.487425 INFO: [examples.PartialSyncProducerApp] Publish: /a-2/1
    1546280473.466515 INFO: [examples.PartialSyncProducerApp] Publish: /a-7/1
    1546280481.882258 INFO: [examples.PartialSyncProducerApp] Publish: /a-0/1
    1546280484.201229 INFO: [examples.PartialSyncProducerApp] Publish: /a-4/1
    1546280489.348968 INFO: [examples.PartialSyncProducerApp] Publish: /a-9/1
    1546280491.420391 INFO: [examples.PartialSyncProducerApp] Publish: /a-3/1


  • In a new terminal, enable logging for the consumer.

    export NDN_LOG="examples.PartialSyncConsumerApp=INFO"
  • Run the consumer to subscribe to 5 random prefixes from the publisher on /sync.

    psync-consumer /sync 5
  • Sample output from the consumer shows that it received updates only for the subscribed prefixes:

    1546280436.502769 INFO: [examples.PartialSyncConsumerApp] Subscribing to: /a-7
    1546280436.502888 INFO: [examples.PartialSyncConsumerApp] Subscribing to: /a-9
    1546280436.502911 INFO: [examples.PartialSyncConsumerApp] Subscribing to: /a-8
    1546280436.502934 INFO: [examples.PartialSyncConsumerApp] Subscribing to: /a-4
    1546280436.502956 INFO: [examples.PartialSyncConsumerApp] Subscribing to: /a-5
    1546280458.211188 INFO: [examples.PartialSyncConsumerApp] Update: /a-8/1
    1546280469.954886 INFO: [examples.PartialSyncConsumerApp] Update: /a-5/1
    1546280473.467116 INFO: [examples.PartialSyncConsumerApp] Update: /a-7/1
    1546280484.256181 INFO: [examples.PartialSyncConsumerApp] Update: /a-4/1
    1546280489.349793 INFO: [examples.PartialSyncConsumerApp] Update: /a-9/1

Full Sync Example

To demonstrate the full sync mode of PSync, psync-full-sync can be run on a machine after starting NFD.

  • Enable logging for the full sync demo app.

    export NDN_LOG="examples.FullSyncApp=INFO"
  • Run the full sync example with sync prefix /sync, user prefix /a, and publish three updates for each user prefix: /a-0 and /a-1. This will simulate node a.

    psync-full-sync /sync /a 2 3
  • Repeat for another user prefix, to simulate node b.

    psync-full-sync /sync /b 2 3

    We should see that node a and node b have received each other’s updates.

  • Sample output from node a shows that it received all updates from node b successfully:

    1546282730.759387 INFO: [examples.FullSyncApp] Update /b-1/1
    1546282741.143225 INFO: [examples.FullSyncApp] Publish: /a-1/1
    1546282749.375854 INFO: [examples.FullSyncApp] Publish: /a-0/1
    1546282750.263246 INFO: [examples.FullSyncApp] Update /b-0/1
    1546282765.875118 INFO: [examples.FullSyncApp] Update /b-1/2
    1546282783.777807 INFO: [examples.FullSyncApp] Publish: /a-0/2
    1546282794.565507 INFO: [examples.FullSyncApp] Publish: /a-0/3
    1546282794.896895 INFO: [examples.FullSyncApp] Publish: /a-1/2
    1546282803.839416 INFO: [examples.FullSyncApp] Update /b-0/2
    1546282804.785867 INFO: [examples.FullSyncApp] Update /b-1/3
    1546282845.273772 INFO: [examples.FullSyncApp] Publish: /a-1/3
    1546282855.102790 INFO: [examples.FullSyncApp] Update /b-0/3
  • Sample output from node b:

    1546282730.758296 INFO: [examples.FullSyncApp] Publish: /b-1/1
    1546282741.144027 INFO: [examples.FullSyncApp] Update /a-1/1
    1546282749.376543 INFO: [examples.FullSyncApp] Update /a-0/1
    1546282750.262244 INFO: [examples.FullSyncApp] Publish: /b-0/1
    1546282765.296005 INFO: [examples.FullSyncApp] Publish: /b-1/2
    1546282783.778769 INFO: [examples.FullSyncApp] Update /a-0/2
    1546282794.566485 INFO: [examples.FullSyncApp] Update /a-0/3
    1546282795.374339 INFO: [examples.FullSyncApp] Update /a-1/2
    1546282803.838394 INFO: [examples.FullSyncApp] Publish: /b-0/2
    1546282804.033214 INFO: [examples.FullSyncApp] Publish: /b-1/3
    1546282845.274680 INFO: [examples.FullSyncApp] Update /a-1/3
    1546282855.101780 INFO: [examples.FullSyncApp] Publish: /b-0/3