feat: enable keep alive on configuration by default

[juanpicado]

Add by default the keep alive configuration for the newer installations.

Example: cc5d786

If this goes well, I'd enabled it directly for older installations which upgrade without have to change configuration in the near future if no troubles are reported.

https://github.com/request/request#requestoptions-callback
https://nodejs.org/api/http.html#http_new_agent_options

From docs

keepAlive: true,      // Keep sockets around even when there are no outstanding requests, so they can be used for future requests without having to reestablish a TCP connection. Defaults to false
maxSockets: 40, // Maximum number of sockets to allow per host. Defaults to Infinity.
maxFreeSockets: 10   // Maximum number of sockets to leave open in a free state. Only relevant if keepAlive is set to true. Defaults to 256.

[dnafication]

What would be preferred approach of testing this?

[juanpicado]

What would be preferred approach of testing this?

Actually was tested already, there is some background behind of this, projecs as react-native-windows, create-react-app, verdaccio itself (cc5d786) or recently pnpm pnpm/registry-mock#2 pnpm/pnpm@33ef97c have need it to upgrade their settings to improve performance in CI (those free does not provide too much power). For the other side even locally a registry might not be able to open new connections either for network restrictions, firewalls ect etc, with keepAlive we fix this.

I know this will be a boost in performance, maybe should be enable by default via code if you think is better.

[dnafication]

Sniffed around with wireshark to check the open sockets.