Improve error reporting when Truffle fails to connect to JSON RPC

[gnidan]

Issue

Currently, the error appears as "Invalid JSON RPC response" with very little representation of underlying problem

Expected Behavior

The error should indicate that Truffle has trouble connecting to Ethereum node software.

Specific Requirements

• Error message should include possible failure cases. Feel free to use an error message that has multiple lines and formatting, i.e.,

  Could not connect to your Ethereum client. Please check that your Ethereum client:
  
  - is running
  - is accepting RPC connections (i.e., "--rpc" option is used in geth)
  - is accessible over the network
  

  And perhaps we can have the error message link to a FAQ or document that describes this (ignore this requirement if you can't find a useful document)

• The error itself should be wrapped in truffle-error. Note that Truffle uses truffle-error as a "flag" to print out error messages nicely instead of showing a full stack trace.

(from trufflesuite/truffle-config#4 (comment))

[dotnetspec]

Thanks. I realized that Truffle was not able to connect to the Ethereum client. However, I don't know why it wouldn't connect.

What steps can I take to make the connection happen?

Thanks,

[gnidan]

@dotnetspec Ensure that your client is running and your truffle.js file is configured correctly. Beyond that, the Truffle gitter is probably the best place to go for troubleshooting. (Underlying issues can vary wildly)

[gnidan]

After wrapping the underlying web3 error, here's what it looks like: