Ownership trasfer to crowdsale contract fails while deploying in truffle

Question

I have created a "Token" and the "Crowdsale" contract as mentioned in the openzeppelin. Below is my deployment code in truffle. I am new to ICO related coding and solidity. The question may be very simple but I am trying hard to find a answer, could you please assist?

Question

1. I understand the Crowd sale contract needs to have ownership of the token contract. Is it correct ?

2. If the ownership has to be transferred, how to do that while deploying itself ?

How to transfer the ownership of the token contract

2_deploy_ico.js

return deployer
.then(() => { 
return deployer.deploy(SampleCrowdsaleToken, "Sample Crowdsale Token","SCT",18);
})
.then(() => { 
console.log("Token Address : ",SampleCrowdsaleToken.address) ;
return deployer.deploy(SampleCrowdsale,openingTime,closingTime,rate,wallet,cap,SampleCrowdsaleToken.address,goal);
}).then(() => { 
console.log("Sale Address : ",SampleCrowdsale.address) ;
// TODO: transfer ownerhship of the token to the crowdsale for minting
// Currently doing that in the UI
SampleCrowdsaleToken.transferOwnership(SampleCrowdsale.address);
console.log("!!! Success !!!") ;

});

Answer 1

Does the Crowdsale contract need to own the token contract?

Not necessarily. It is not a requirement that the Crowdsale contract actually owns the Token contract. You can simply mint/transfer tokens to the Crowdsale contract, which will then be responsible to sell the tokens.

A standard Crowdsale implementation and deployment methodology can be found here: https://www.ethereum.org/crowdsale. It is a very good starting point to get the basics of ICO contracts architecture.

Anyway, how can you transfer contract ownership?

You are probably calling the right method in the deployment script. However you are not calling it on the specific instance of the contract that you deployed. You need to use something like

.then((deployedInstance) => deployedInstance.transferOwnership(...));

Straight after the deployer.deploy(...) call, to call the deployed instance. Hope this helps.