Uploading a Smart Contract

This tutorial covers how to create a circuit on a splinter network between two nodes and upload a smart contract via the circuit.

Prerequisites

  • A splinter network with at least two nodes running. The tutorial will refer to the two nodes as “alpha” and “beta” respectively
  • The scabbard command line tool installed with experimental features enabled
  • The splinter command line tool installed with experimental features enabled
  • A compiled smart contract. Check here for details on how to create and compile a smart contract

Procedure

  1. Create a new circuit.

    a. Propose the circuit on alpha node.

     $ splinter circuit propose \
     --url http://splinterd-alpha:8080 \
     --key <path_to_alpha_private_key> \
     --node alpha-node-000::tcps://splinterd-alpha:8044 \
     --node beta-node-000::tcps://splinterd-beta:8044 \
     --service scabbard-service-alpha::alpha-node-000 \
     --service scabbard-service-beta::beta-node-000 \
     --service-peer-group beta-node-000,alpha-node-000 \
     --service-arg *::admin_keys=<alpha_node_pub_key> \
     --service-arg scabbard-service-beta::peer_services=alpha-node-000 \
     --service-arg scabbard-service-alpha::peer_services=beta-node-000 \
     --service-type *::scabbard \
     --management tutorial \
     --auth-type trust

    The --service-args supplied are specific to the scabbard service and are required in order to use and configure smart contracts. admin_keys identify who is allowed to add permissions to a contract and peer_services is for identifying which parties are needed for consensus.

    b. The circuit ID can be obtained by running the proposals command. The following example sets the CIRCUIT_ID environment variable; this environment variable is for the purposes of this procedure and is not used directly by the splinter CLI commands.

    Set CIRCUIT_ID based on the output of the proposals subcommand; for example:

     $ splinter circuit proposals --url http://splinterd-beta:8080

 ID                                   MANAGEMENT MEMBERS
 01234567-0123-0123-0123-012345678901 tutorial   alpha-node-000;beta-node-000

     $ export CIRCUIT_ID=01234567-0123-0123-0123-012345678901

    c. Vote to accept the circuit on node beta.

     $ splinter circuit vote \
     --key <path_to_beta_private_key> \
     --url http://splinterd-beta:8080 $CIRCUIT_ID --accept

    You have now established a circuit between node alpha and node beta based on the provided circuit definition.

    d. Verify the circuit has been established.

     $ splinter circuit list --url http://splinterd-alpha:8080

 ID                                   MANAGEMENT MEMBERS
 01234567-0123-0123-0123-012345678901 tutorial   alpha-node-000;beta-node-000

  2. Package smart contract.

    a. Create manifest.yaml.

    The manifest contains the inputs, outputs, version, and the contract name. Below is a sample manifest.

     name: my_contract
 version: '1.0'
 inputs:
   - '5b7349'
 outputs:
   - '5b7349'

    b. Bundle the manifest and the compiled wasm for the smart contract into a tarball that has the scar extension.

     $ tar -jcvf my_contract.scar my_contract.wasm manifest.yaml

  3. Create contract registry for smart contract.

    Each contract needs a contract registry to be created that keeps track of versions of the smart contract as well as the contract’s owners.

     $ scabbard cr create my_contract \
     --owner <alpha_node_public_key> \
     --key <path_to_alpha_node_private_key> \
     --url http://splinterd-alpha:8080 \
     --service-id $CIRCUIT_ID::scabbard-service-alpha

  4. Upload the smart contract.

    $ scabbard contract upload ./my_contract.scar \
    --key <path_to_alpha_node_private_key> \
    --url http://splinterd-alpha:8080 \
    --service-id $CIRCUIT_ID::scabbard-service-alpha

  5. Create the namespace registry for the smart contract.

    A namespace will need to be created for each namespace in the contract’s manifest. The namespace registry stores the namespace, the owners of the namespace, and the permissions given to that namespace. A namespace is a state address prefix used to identify a portion of state.

     $ scabbard ns create 5b7349 \
    --owner <alpha_node_public_key> \
    --key <path_to_alpha_node_private_key> \
    --url http://splinterd-alpha:8080 \
    --service-id $CIRCUIT_ID::scabbard-service-alpha

  6. Create contract permissions.

    The perm command creates permissions that allow the smart contract to access state. The below command gives the smart contract both read and write permissions.

    $ scabbard perm 5b7349 my_contract --read --write \
    --key <path_to_alpha_node_private_key> \
    --url http://splinterd-alpha:8080 \
    --service-id $CIRCUIT_ID::scabbard-service-alpha

  7. List uploaded smart contracts.

     $ scabbard contract list -U 'http://splinterd-beta:8080' \
     --service-id $CIRCUIT_ID::scabbard-service-beta

 NAME        VERSIONS OWNERS
 sawtooth_xo  1.0     <owner_public_key>

  8. Display uploaded smart contract.

     $ scabbard contract show my_contract:1.0 \
     -U 'http://splinterd-beta:8080' \
     --service-id $CIRCUIT_ID::scabbard-service-beta

 name: my_contract
 version: '1.0'
 inputs:
   - '5b7349'
 outputs:
   - '5b7349'

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