Brownie / Rinkeby: Unable to expand environment variable in host setting

user_14209166 0
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I was following the tutorial from this video and now I'm stuck during deploying a contract to rinkeby testnet.

If I run brownie run scripts/deploy.py --network rinkeby I get an error:

BrownieProject is an active project.
  File "brownie/_cli/__main__.py", line 64, in main
    importlib.import_module(f"brownie._cli.{cmd}").main()
  File "brownie/_cli/run.py", line 44, in main
    network.connect(CONFIG.argv["network"])
  File "brownie/network/main.py", line 40, in connect
    web3.connect(host, active.get("timeout", 30))
  File "brownie/network/web3.py", line 52, in connect
    uri = _expand_environment_vars(uri)
  File "brownie/network/web3.py", line 183, in _expand_environment_vars
    raise ValueError(f"Unable to expand environment variable in host setting: '{uri}'")
ValueError: Unable to expand environment variable in host setting: 'https://rinkeby.infura.io/v3/$WEB3_INFURA_PROJECT_ID'

I checked the brownie-config.yaml file and .env for typing errors but haven't found anything.

brownie-config.yaml

dotenv: .env
wallets:
  from_key: ${PRIVATE_KEY}

I already created an infura api and add it in the .env file as export WEB3_INFURA_PROJECT_ID=abc12345656789.

If I run the command brownie run scripts/deploy.py everything works fine so I can exclude any typo. Does someone have an idea what's the problem?

I use Brownie v1.17.2

brownie blockchain solidity ethereum python
3 Answers

I believe you are not loading environment variable in your file. install python-dotenv

  pip install python-dotenv

In your deploy.py if .env is in the same directory:

import os
from dotenv import load_dotenv 

#default directory for .env file is the current directory
#if you set .env in different directory, put the directory address load_dotenv("directory_of_.env)
load_dotenv()

then use it like this:

 private_key=os.getenv("PRIVATE_KEY")
user_102628050

Typically, this means your environment variables are not set correctly, and it looks like in this case it's your WEB3_INFURA_PROJECT_ID.

You can fix it by setting the variable in your .env file and adding dotenv: .env to your brownie-config.yaml.

brownie-config.yaml:

dotenv: .env

.env:

export WEB3_INFURA_PROJECT_ID=YOUR_PROJECT_ID_HERE

Remember to save these files.

Additionally, you should be on at least brownie version v1.14.6. You can find out what version you're on with:

brownie --version

If you know how to set environment variables you might want to check if you're setting them correctly.

user_119695920

if you are sure you set the .env correctly you can try sourcing your .env file in the terminal:

source .env

and then try running your script again.

user_193668290
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