Error when running Earlybird in docker. The channel goes into deadlock

[grinish21]

[afham123]

Tech stack

Broadcast and subscribe concepts or the publish-subscribe (pub-sub) pattern is being used in the earlybird scan. This pattern allows one entity (the broadcaster or publisher) to send messages to multiple subscribers. It is implemented using channels.
A broadcaster is responsible for sending messages to multiple subscribers and all subscribers receive the same messages. Where as A subscriber listens for messages from the broadcaster.
There are two scan write being used, one is using the pun-sub and the other is using the simple for loop listening to the channel, Both of them needs to be called differently. As of now both are being called with a same process which is initiating the issue.

RCA

The issue arises due to a deadlock in the program. The ChannelReceiver goroutines are waiting for hits to be sent to the channel (HitChannel) so they can process them. At the same time, the WaitGroup (wg) is waiting for the ChannelReceiver goroutines to finish their execution and call wg.Done(). However, since the channel is not being closed after all hits are sent, the ChannelReceiver goroutines remain blocked, waiting for more data that will never arrive.
This creates a circular dependency:

1. The ChannelReceiver goroutines are waiting for the channel to be closed or for more data to arrive.
2. The WaitGroup is waiting for the ChannelReceiver goroutines to finish and call wg.Done().
   As a result, neither can proceed, leading to a deadlock. This causes the scan process to terminate non-gracefully, leaving resources uncleaned and the program in an inconsistent state.

Fix

Removing the WaitGroup Dependency on the Receivers:
The WaitGroup was previously waiting for the receivers to finish processing before proceeding. This dependency was removed, allowing the receivers to process data independently without blocking the main thread. This change eliminated the circular dependency that caused the deadlock.

Reordering Initialization:
The receivers were set up first, followed by the channel broadcaster, ensuring that the receivers were ready to process data as soon as the broadcaster started sending it. Additionally, proper cleanup was ensured by closing all goroutines gracefully, preventing resource leaks and ensuring a smooth shutdown.