Handle EADDRINUSE Network Startup Error

[mikeseese]

Several users are experiencing the below error. This issue will serve as the main issue to address this error.

Error: listen EADDRINUSE <IP_ADDRESS>:<PORT>

Potential Causes

• There is a possible bug in Ganache where if it restarts quickly, the port isn't unbound before restart.
• There is more than one instance of Ganache running; which is not supported currently
• There is another program using that port

Mitigations/Work-arounds (aka how to fix the issue until we patch this)

• Stop all instances of Ganache, wait a minute, and then only start one instance of Ganache
• Change the interface and/or port in the Settings file as to prevent collisions from another program (be sure to restart Ganache after saving the Settings file):
  • MacOS: ~/Library/Application\ Support/Ganache/Settings
  • Windows: %APPDATA%\Ganache\Settings
  • Linux: either $XDG_CONFIG_HOME/Ganache/Settings or ~/.config/Ganache/Settings

Description

As part of this issue, the following will be addressed:

• Determine why these errors are happening
• Address all causes for this same symptom (and open new issues if the cause is drastically different)
• Add a message instead of the error screen which will say that the IP/Port combo used is conflicting with another process, providing some generic instructions for trying to solve the problem before submitting an issue on GitHub
• Allow users to change settings rather than being stuck on an error page

Work will likely overlap with #666