support setting raft server init options and raft callback in raft_launcher::init()

[sheepgrass]

support setting raft server init options and raft callback in raft_launcher::init()

[greensky00]

Thanks @sheepgrass , some minor comments.

[greensky00]

Could you please use reference?

const raft_server::init_options& opt = raft_server::init_options()

[sheepgrass]

Agree.

Actually, I was just copied from your unit test case :p

NuRaft/tests/unit/raft_package_fake.hxx

Lines 51 to 54 in 7501788

	void initServer(raft_params* given_params = nullptr,
	const raft_server::init_options opt =
	raft_server::init_options(),
	cb_func::func_type raft_callback = nullptr)

[greensky00]

Oh, good catch, it also needs to be fixed. Thanks :)

[greensky00]

As I mentioned in the previous PR, I'd like to suggest you to move cb_func::func_type raft_callback inside raft_server::init_options like this:

struct init_options {
    // ...

    bool skip_initial_election_timeout_;
    
    cb_func::func_type raft_callback_;
};

and invoke ctx->set_cb_func(...) inside the constructor of raft_server. Then launcher doesn't need to call set_cb_func, thus we can get benefit for both launcher and raft_server. What do you think?

[sheepgrass]

Sorry that I didn't notice you mentioned about moving it to raft_server constructor. I will make the change.

Actually, for this change, I am also taken reference to your unit test case:

NuRaft/tests/unit/raft_package_fake.hxx

Lines 85 to 90 in 7501788

	ctx = new context( sMgr, sm, listener, myLog,
	rpcCliFactory, scheduler, params );
	if (raft_callback) {
	ctx->set_cb_func(raft_callback);
	}
	raftServer = cs_new<raft_server>(ctx, opt);