Executor¶

Class Name	Executor
Extends	Logger
Source	executor.ts
Examples	executor.spec.ts

The executor is used for

making contract calls
executing contract transactions
creating contracts
send EVEs to another account or contract

The signer requires you to have a contract instance, either by

loading the contract via Description helper (if the contract has an abi at its description)
loading the contract via ContractLoader helper (if the contract has not abi at its description)
directly via web3.js.

constructor¶

new Executor(options);

Creates a new Executor instance.

The Executor allows to pass the defaultOptions property to its constructor. This property contains options for transactions and calls, that will be used if no other properties are provided in calls/transactions. Explicitly passed options always overwrite default options.

Parameters¶

options - ExecutorOptions: options for ServiceContract constructor.
- config - any: configuration object for the executor instance
- defaultOptions - any (optional): default options for web3 transactions/calls
- eventHub - EventHub: EventHub instance
- signer - SignerInterface: SignerInterface instance
- web3 - Web3: Web3 instance
- log - Function (optional): function to use for logging: (message, level) => {...}
- logLevel - LogLevel (optional): messages with this level will be logged with log
- logLog - LogLogInterface (optional): container for collecting log messages
- logLogLevel - LogLevel (optional): messages with this level will be pushed to logLog

Returns¶

Executor instance

Example¶

const executor = new Executor({
    config,
    eventHub,
    signer,
    web3
  });

init¶

executor.init(name);

Initialize executor.

Parameters¶

options - any: object with the property “eventHub” (of the type EventHub)
- eventHub - EventHub: The initialized EventHub Module.

Returns¶

void.

Example¶

runtime.executor.init({eventHub: runtime.eventHub})

executeContractCall¶

executor.executeContractCall(contract, functionName, ...args);

Run the given call from contract.

Parameters¶

contract - any: the target contract
functionName - string: name of the contract function to call
...args - any[]: optional array of arguments for contract call. if last arguments is {Object}, it is used as the options parameter

Returns¶

Promise resolves to any: contract calls result.

Example¶

const greetingMessage = await runtime.executor.executeContractCall(
  contract,                               // web3.js contract instance
  'greet'                                 // function name
);

executeContractTransaction¶

executor.executeContractTransaction(contract, functionName, inputOptions, ...functionArguments);

Execute a transaction against the blockchain, handle gas exceeded and return values from contract function.

Parameters¶

contract - any: contract instance
functionName - string: name of the contract function to call
inputOptions - any: options object
- from - string (mandatory): The address the call “transaction” should be made from.
- gas - number (optional): The amount of gas provided with the transaction.
- event - any (optional): object with two properties target (contract name) and eventName
- getEventResult - function (optional): callback function which will be called when the event is triggered. First argument is the full event info, second argument is an options with the event arguments.
- eventTimeout - number (optional): timeout (in ms) to wait for a event result before the transaction is marked as error
- estimate - boolean (optional): Should the amount of gas be estimated for the transaction (overwrites gas parameter)
- force - string (optional): Forces the transaction to be executed. Ignores estimation errors
- autoGas - number (optional): enables autoGas 1.1 ==> adds 10% to estimated gas costs. value capped to current block.
- value- number (optional): Allows to specify the amount of funds for transfer
...functionArguments - any[]: optional arguments to pass to contract transaction

Returns¶

Promise resolves to: no result (if no event to watch was given), the event (if event but no getEventResult was given), the value returned by getEventResult(eventObject, arguments).

Because an estimation is performed, even if a fixed gas cost has been set, failing transactions are rejected before being executed. This protects users from executing transactions, that consume all provided gas and fail, which is usually not intended, especially if a large amount of gas has been provided. To prevent this behavior for any reason, add a force: true to the options, though it is not advised to do so.

To allow to retrieve the result of a transaction, events can be used to receive values from a transaction. If an event is provided, the transaction will only be fulfilled, if the event is triggered. To use this option, the executor needs to have the eventHub property has to be set. Transactions, that contain event related options and are passed to an executor without an eventHub will be rejected immediately.

Example¶

const accountId = '0x...';
const greetingMessage = await runtime.executor.executeContractTransaction(
  contract,                               // web3.js contract instance
  'setData',                              // function name
  { from: accountId, },                   // perform transaction with this account
  123,                                    // arguments after the options are passed to the contract
);

Provided gas is estimated automatically with a fault tolerance of 10% and then used as gas limit in the transaction. For a different behavior, set autoGas in the transaction options:

const greetingMessage = await runtime.executor.executeContractTransaction(
  contract,                               // web3.js contract instance
  'setData',                              // function name
  { from: accountId, autoGas: 1.05, },    // 5% fault tolerance
  123,                                    // arguments after the options are passed to the contract
);

or set a fixed gas limit:

const greetingMessage = await runtime.executor.executeContractTransaction(
  contract,                               // web3.js contract instance
  'setData',                              // function name
  { from: accountId, gas: 100000, },      // fixed gas limit
  123,                                    // arguments after the options are passed to the contract
);

Using events for getting return values:

const contractId = await runtime.executor.executeContractTransaction(
  factory,
  'createContract', {
    from: accountId,
    autoGas: 1.1,
    event: { target: 'FactoryInterface', eventName: 'ContractCreated', },
    getEventResult: (event, args) => args.newAddress,
  },
);

executeSend¶

executor.executeSend(options);

Send EVEs to target account.

Parameters¶

options - any: the target contract
- from - string: The address the call “transaction” should be made from.
- to - string: The address where the eve’s should be send to.
- value - number: Amount to send in Wei

Returns¶

Promise resolves to void: resolved when done.

Example¶

await runtime.executor.executeSend({
  from: '0x...',                          // send from this account
  to: '0x...',                            // receiving account
  value: web3.utils.toWei('1'),           // amount to send in Wei
});

createContract¶

executor.createContract(contractName, functionArguments, options);

Creates a contract by contstructing creation transaction and signing it with private key of options.from.

Parameters¶

contractName - string: contract name (must be available withing contract loader module)
functionArguments - any[]: arguments for contract creation, pass empty Array if no arguments
options - any: options object
- from - string: The address the call “transaction” should be made from.
- gas - number: Provided gas amout for contract creation.

Returns¶

Promise resolves to any: new contract.

Example¶

const newContractAddress = await runtime.executor.createContract(
  'Greeter',                              // contract name
  ['I am a demo greeter! :3'],            // constructor arguments
  { from: '0x...', gas: 100000, },        // gas has to be provided with a fixed value
);