updateOracle

The updateOracle method serves to refresh an existing oracle with the latest data fetched from the linked API. This ensures that the oracle maintains up-to-date information, enhancing its reliability and usefulness for downstream applications.

Usage

As an example, we will utilize the CoinGecko public API oracle, which provides the Ethereum price in USD: CoinGecko Ethereum API.

// create an observable
const updateOracleObservable = factory.updateOracle(
  {
    JSONPath: "$['ethereum']['usd']",
    body: '',
    dataType: 'number',
    dataset: '0x0000000000000000000000000000000000000000',
    headers: {},
    method: 'GET',
    url: 'https://api.coingecko.com/api/v3/simple/price?ids=ethereum&vs_currencies=usd',
  },
  {
    workerpool: '0xa5de76...',
    targetBlockchains: [137],
  }
);

// subscribe to the observable and start the workflow
updateOracleObservable.subscribe({
  next: (data) => {
    console.log('next', data);
  },
  error: (error) => {
    console.log('error', error);
  },
  complete: () => {
    console.log('Oracle update Completed');
  },
});

Parameters

paramSet or paramSetCid Required *

TIP

• The oracle ParamSet describes the parameters used to feed the oracle.

• Any different ParamSet has a unique ParamSetCid which is the Content ID of the document on IPFS. With a ParamSetCid anyone can retrieve the ParamSet from IPFS.

• ParamSet of the Oracle to update.

const paramSet: ParamSet = { 
  JSONPath: "$['ethereum']['usd']",
  body: '',
  dataType: 'number',
  dataset: '0x0000000000000000000000000000000000000000',
  headers: {},
  method: 'GET',
  url: 'https://api.coingecko.com/api/v3/simple/price?ids=ethereum&vs_currencies=usd',
};

const updateOracleObservable = factory.updateOracle(
  paramSet
);

• ParamSet CID of the Oracle to update.

const paramSetCid: ParamSetCID =
  'QmbeY27w6dKxNQnGXih4AaotgNY3XuZ2yzbi2ZWQfRApqs';

const updateOracleObservable = factory.updateOracle(
  paramSetCid
);

workerpool

Address of the workerpool that should perform the update.

const updateOracleObservable = factory.updateOracle(
  'QmbXhtjAJysMMA69KkB8KohsEDTZA2PXuhYdAQcHjjQFit',
  {
    workerpool: '0xa5de76...',
    targetBlockchains: [137],
  }
);

TIP

iExec currently offers a production workerpool located at the Ethereum Name Service (ENS) address prod-v8-bellecour.main.pools.iexec.eth. This is the default workerpool for running confidential computations on the iExec platform.

targetBlockchains

Array of target blockchain chainId where the oracle is deployed. 1 for Ethereum mainnet, 137 for Polygon mainnet.

const updateOracleObservable = factory.updateOracle(
  'QmbXhtjAJysMMA69KkB8KohsEDTZA2PXuhYdAQcHjjQFit',
  {
    workerpool: '0xa5de76...',
    targetBlockchains: [1, 137],
  }
);

Return value

Observable<UpdateOracleMessage>

import type {
  UpdateOracleMessage, // any `data` the `next(data)` handler can receive

  // all `data` types
  EnsureParamsMessage, // check ParamSet can be found on IPFS
  EnsureParamsUploadMessage, // the ParamSet will be uploaded on IPFS
  EnsureParamsSuccessMessage, // ParamSet exists on IPFS
  FetchAppOrderMessage, // fetching app order
  FetchAppOrderSuccessMessage, // app order found
  FetchDatasetOrderMessage, // fetching dataset order (only for oracles using API key dataset)
  FetchDatasetOrderSuccessMessage, // app order found (only for oracles using API key dataset)
  FetchWorkerpoolOrderMessage, // fetching workerpool order
  FetchWorkerpoolOrderSuccessMessage, // app workerpool found
  RequestOrderSignatureSignRequestMessage, // asking the user to sign the request order
  RequestOrderSignatureSuccessMessage, //
  MatchOrdersSignTxRequestMessage, // asking the user to sign the transaction to match the orders and make a deal
  MatchOrdersSuccessMessage, // orders matched
  TaskUpdatedMessage, // notifies a task status change
  UpdateTaskCompletedMessage, // the oracle update task is completed
} from '@iexec/iexec-oracle-factory-wrapper';

TIP

Nothing happens before subscribe() is called on the returned observable.

You can provide custom next, complete and error callback methods to subscribe

// method to call when the workflow goes to a new step
const nextCallback: ObservableNext<UpdateOracleMessage> = (data) => {
  // your logic
};

// method to call when the workflow completes successfully
const completeCallback: ObservableComplete = () => {
  // your logic
};

// method to call when the workflow fails
const errorCallback: ObservableError = (error: Error) => {
  // your logic
};

updateOracleObservable.subscribe({
  next: nextCallback,
  complete: completeCallback,
  error: errorCallback,
});