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Quickstart

This quickstart takes you from a running ledger to a traced transaction: set up the example ledger, submit a command, trace it, and read it as another party. Before you start:

  • dpm trace is registered, as described in Register with DPM.
  • You have a clone of the repository, because the example ledger lives in examples/: git clone https://github.com/walnuthq/dpm-trace.git && cd dpm-trace.
  • Java 17 or newer, curl, and python3 are on your PATH.
  • The Canton JAR is in the DPM cache. If it is missing, run dpm install <sdk-version>, or set CANTON_JAR=<path-to-canton.jar>.

Set up the example ledger​

The example used in these docs comes from examples/asset. Its Asset template has an issuer, an owner, a name, and a quantity. The owner can Split it into two assets, Transfer it, Withdraw part of its quantity, or Burn it.

To set everything up, run up.sh. It builds the DAR, starts a local Canton, uploads the DAR, creates the Issuer, Alice, and Bob parties, and exports their IDs. The network is defined in examples/devnet-trace.conf: two participants on one synchronizer, with Issuer and Alice on participant1 and Bob on participant2.

starting Canton (pid 28225, log <path-to-dpm-trace>/examples/.up/canton.log) ...
export LEDGER='http://127.0.0.1:6113'
export LEDGER2='http://127.0.0.1:6123'
export ISSUER='Issuer::12206747c65243c1f7fc92787d5c7d0af50006b160c6231ef19a9125054453278dc7'
export ALICE='Alice::12206747c65243c1f7fc92787d5c7d0af50006b160c6231ef19a9125054453278dc7'
export BOB='Bob::12206f5e34dacf518ca87d87e1fddc5eee2be0f9f879e1694620b51e44a4a976d831'
Canton is ready: participant1 http://127.0.0.1:6113, participant2 http://127.0.0.1:6123
To use in another shell run: source examples/.env
Stop Canton with: ./up.sh down

The variables LEDGER, ISSUER, ALICE, and BOB are used in every example below. In a new shell, run source examples/.env to set them. When you are done, stop Canton with up.sh down.

If you prefer to set this up yourself, start a local ledger with dpm sandbox (or LocalNet for several validators), upload the DAR, and create the parties by following the Canton documentation.

Submit a command​

To create an Asset as the issuer, we use dpm trace submit:

dpm trace submit \
  --submitter "$LEDGER" \
  --act-as "$ISSUER" \
  --template '#asset:Asset:Asset' \
  --arg issuer="$ISSUER" --arg owner="$ALICE" \
  --arg name=GOLD --arg quantity=100

Output is the update ID:

12208cc4c75617b64417ef7d2b3a5a4352156b1082e6ca2d0569686eecd1e9f82cab
  • --submitter: URL of the participant's JSON Ledger API.
  • --act-as: the party that submits the command.
  • --template: the template to create, as #package:Module:Template.
  • --arg: input field of the contract; in our example issuer is Issuer, owner is Alice, name is the name of the asset (GOLD), and quantity is how much of it there is (100).

Trace the update ID​

Pass the update ID and the party to read as.

dpm trace 12208cc4c75617b64417ef7d2b3a5a4352156b1082e6ca2d0569686eecd1e9f82cab \
  --submitter "$LEDGER" --read-as "$ISSUER"

Both flags are required:

  • --submitter: the participant's JSON Ledger API URL, the ledger to read the update from. Without it, dpm trace has no source and fails with choose a source.
  • --read-as: the party whose view of the update you want. Events and data that this party is not allowed to see are left out.
Canton trace
  update:       12208cc4c75617b64417ef7d2b3a5a4352156b1082e6ca2d0569686eecd1e9f82cab
  source:       ledger-json-api (http://127.0.0.1:6113/v2/updates/update-by-id)
  offset:       25
  record time:  2026-10-21T12:58:13.729004Z
  synchronizer: local::1220e1a34ed2ad1cdc3fd97d63216fe68977ca385f9d0694b39f6f8221063fd183af
  read-as:      Issuer (Issuer::12206747...278dc7)
  visibility:   Authorized participant projection. Private data outside these party rights is not available.
  events:       +1 create, >0 exercise, x0 archive
  parties:
    Alice = Alice::12206747c65243c1f7fc92787d5c7d0af50006b160c6231ef19a9125054453278dc7
    Issuer = Issuer::12206747c65243c1f7fc92787d5c7d0af50006b160c6231ef19a9125054453278dc7

Trace
└── [0] CREATE Asset:Asset
    ├── contract: 0049e39faff71061552be32eb5b47bd49a014a08072f48416c6acd0a7afe49d...
    ├── signatories: Issuer
    ├── observers: Alice
    ├── witnesses: Issuer
    └── payload: { issuer: Issuer, owner: Alice, name: GOLD, quantity: 100 }

The output has a header and a tree of events, where each event is one line, like [ID] KIND Template.Choice. See Reading trace output for the details of every field.

In this trace there is one CREATE event: Issuer signs it, and Alice sees it as an observer.

Read the update as another party​

Read the same update as Alice.

dpm trace 12208cc4c75617b64417ef7d2b3a5a4352156b1082e6ca2d0569686eecd1e9f82cab \
  --submitter "$LEDGER" --read-as "$ALICE"

Output:

Canton trace
  update:       12208cc4c75617b64417ef7d2b3a5a4352156b1082e6ca2d0569686eecd1e9f82cab
  source:       ledger-json-api (http://127.0.0.1:6113/v2/updates/update-by-id)
  offset:       25
  record time:  2026-10-21T12:58:13.729004Z
  synchronizer: local::1220e1a34ed2ad1cdc3fd97d63216fe68977ca385f9d0694b39f6f8221063fd183af
  read-as:      Alice (Alice::12206747...278dc7)
  visibility:   Authorized participant projection. Private data outside these party rights is not available.
  events:       +1 create, >0 exercise, x0 archive
  parties:
    Alice = Alice::12206747c65243c1f7fc92787d5c7d0af50006b160c6231ef19a9125054453278dc7
    Issuer = Issuer::12206747c65243c1f7fc92787d5c7d0af50006b160c6231ef19a9125054453278dc7

Trace
└── [0] CREATE Asset:Asset
    ├── contract: 0049e39faff71061552be32eb5b47bd49a014a08072f48416c6acd0a7afe49d...
    ├── signatories: Issuer
    ├── observers: Alice
    ├── witnesses: Alice
    └── payload: { issuer: Issuer, owner: Alice, name: GOLD, quantity: 100 }

Alice is the owner of the asset, so she sees the same tree.

Now read the same update as Bob.

dpm trace 12208cc4c75617b64417ef7d2b3a5a4352156b1082e6ca2d0569686eecd1e9f82cab \
  --submitter "$LEDGER" --read-as "$BOB"

Output:

error: POST http://127.0.0.1:6113/v2/updates/update-by-id failed with HTTP 404: {"code":"UPDATE_NOT_FOUND","cause":"Update not found, or not visible.","correlationId":null,"traceId":"48ceb25a4d9490adf9c59cfe0329dd18","context":{"participant":"participant1","definite_answer":"false","tid":"48ceb25a4d9490adf9c59cfe0329dd18","category":"11"},"resources":[["ErrorResource(UPDATE_ID)","12208cc4c75617b64417ef7d2b3a5a4352156b1082e6ca2d0569686eecd1e9f82cab"]],"errorCategory":11,"grpcCodeValue":5,"retryInfo":null,"definiteAnswer":null}

Bob is not a stakeholder of the asset, so the ledger returns UPDATE_NOT_FOUND: the update is not visible to him. Bob is hosted on participant2, not on the participant behind LEDGER. To ask Bob's own participant, use LEDGER2:

dpm trace 12208cc4c75617b64417ef7d2b3a5a4352156b1082e6ca2d0569686eecd1e9f82cab \
  --submitter "$LEDGER2" --read-as "$BOB"

The answer is the same UPDATE_NOT_FOUND, now with "participant":"participant2" in its context, because even on his own participant Bob is not a stakeholder of this asset.