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Questions tagged [chainlink]

Chainlink is a decentralized oracle technology connecting smart contracts on any blockchain to data providers, web APIs, enterprise systems, cloud services, IoT devices, payment systems, other blockchains, and more. This tag should be applied to any question about building or debugging decentralized oracles with Chainlink.

Chainlink is a technology for connecting smart contracts on any blockchain to data providers, web APIs, enterprise systems, cloud services, IoT devices, payment systems, other blockchains, and much more. The technology was envisioned by Sergey Nazarov, Ari Juels, and Steve Ellis. The Chainlink whitepaper was published in 2017 and the mainnet went live on Ethereum on May 2019. Chainlink is being built with .

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Error HH12: Trying to use a non-local installation of Hardhat, which is not supported. Please install Hardhat locally using npm or Yarn, and try again

I've been working on a Hardhat project for sometime. After a while, when I run npx hardhat node to start the HH server, I get the error below: I tried researching the error and found this on the hardhat site HH12: Hardhat is not installed or…
KelvinIOT
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How to locally unit-test Chainlink's Verifiable Random Function?

Context While trying to set up a basic self-hosted unit testing environment (and CI) that tests this Chainlink VRF random number contract, I am experiencing slight difficulties in how to simulate any relevant blockchains/testnets locally. For…
a.t.
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ParserError: Source file requires different compiler version (current compiler is 0.8.7+commit.e28d00a7.Emscripten.clang)

I was eventually trying to run this code in remix IDE, where I was running this using 0.6.6 version of Solidity and ran into this error. I've tried using some other versions like 0.8 and 0.6 as well. // SPDX-License-Identifier: MIT pragma solidity…
Gourav Singh Rawat
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Anybody knows why Chainlink's PriceFeed return price value with "int" type while price should always >= 0?

The code for get latest price in PriceFeed is: pragma solidity ^0.6.7; import "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol"; contract PriceConsumerV3 { AggregatorV3Interface internal priceFeed; /** * Network:…
Crypto D
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v0.8 AggregatorV3Interface.sol , its available in @chainlink/contracts?

I get a error when i change the version to 0.8 , but works fine with 0.6, how i see the most recent version? , i tried downloaded from npm install @chainlink/contracts --save, but only works with mock mode. This is my…
Irwing Tello
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How do I convert a uint256 variable to an int256 one?

I was trying to print uint timeStamp by typing return timeStamp; right below return price; from this code: pragma solidity ^0.6.7; import "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol"; contract PriceConsumerV3…
NoahVerner
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INFO: Could not find files for the given pattern(s). Error

I have a problem with using brownie compile in Visual Studio Code as I get a INFO: Could not find files for the given pattern(s). This is the error I get:
user16464304
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Smart Contracts - Chainlink VRF / @openzeppelin/truffle-upgrades compatibility

Right now i am transforming a basic smart contract into a upgradeable smart contract using @openzeppelin/truffle-upgrades So i followed all required steps from the docs but one issue remains: Truffle-Upgrades requires me to replace the constructor…
therealbrudi
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What is a gas lane in chainlink and blockchain?

I do understand the concept of gas in the ethereum blockchain and why gas is needed to compensate miners for providing computing power to the network. However, when I was reading up on the chainlink vrf get a random number documentation it says that…
Daniel_Cawley
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Understanding rounds in Chainlink

I want to use Chainlink to get the price of an asset at a given point in time in the past (which I will refer to as "expiry") in order to settle options. To get a historical price, Chainlink requires to pass in a roundId as argument into the…
Walodja1987
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hardhat : Issues while deploying a NFT to rinkeby network

I started my first blockchain tuto which is: https://www.youtube.com/watch?v=9oERTH9Bkw0&t=696s Repo: https://github.com/PatrickAlphaC/all-on-chain-generated-nft#about-svgs I am trying to deploy a NFT in the Rinkeby testnet with hardhat. Here are…
Remzzer
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Chainlink Large Responses

I run this code from the chainlink documentation but didn't get the image. function requestBytes() public returns (bytes32 requestId) { address oracle = "0xc57B33452b4F7BB189bB5AfaE9cc4aBa1f7a4FD8"; bytes32 specId =…
yamna iftikhar
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Setting Chainlink Keystore Password in Docker-Compose

I'm trying to spin up a chainlink node using docker-compose and am running into this error: error authenticating keystore: No password provided I didn't see an environment variable to set this password. The tutorial…
Robert L
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ContractNotFound: No contract deployed at

I have been involved in the chainlink bootcamp and trying to finishing the final 'Exercise 3: Putting it all together'. However, I am stuck running: brownie run scripts/price_exercise_scripts/01_deploy_price_exercise.py --network…
godhar
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How can I make the data provided by some ChainLink aggregator get updated every time I click on my "getLatestPrice" button?

this is my very first time deploying a contract on Remix as well as learning how to code on Solidity. I have already read this guide and deployed successfully the Smart Contract template provided: pragma solidity ^0.6.7; import…
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