Fix automatic reconnect

[SijmenHuizenga]

Re-connect is broken because the stream spec is cleared on disconnect. By removing the 'clear' statement, subsequent reconnect attempts will work.

[flipflip8952]

• Change title to something that describes the fix, not the problem. Somethig like "Fix automatic reconnect" perhaps?
• Please replace the PR description with something much more concise. Something like "Don't clear stream spec string on disconnect, so that subsequent (re)connect attempts will work" perhaps?
  (You can keep the huge text (AI generated?) elsewhere, e.g. in a comment to the PR.)

[SijmenHuizenga]

@flipflip8952 Thanks for the comment, I've updated the description and title accordingly. 👍

[flipflip8952]

Cheers!

[flipflip8952]

@SijmenHuizenga original description. Moved here so that it doesn't end up in the commit description.

---

FixpositionDriver::Disconnect() clears params_.stream_ after closing the socket, which makes the worker thread's automatic reconnect path permanently fail.

Disconnect() ends with:

sensor_fd_ = -1;
params_.stream_.clear();

The worker loop (fixposition_driver.cpp Worker()) then loops:

else {
    INFO("Reconnecting in %.1f seconds...", params_.reconnect_delay_);
    if (worker_.Sleep(params_.reconnect_delay_ * 1000) == WaitRes::WOKEN) {
        break;
    }
    Connect();
}

But Connect() decides between TCP and serial purely by inspecting params_.stream_:

if (string::StrStartsWith(params_.stream_, "tcpcli://")) { ... }
else if (string::StrStartsWith(params_.stream_, "serial://")) { ... }
WARNING("Bad stream spec: %s", params_.stream_.c_str());
return false;

With params_.stream_ empty, both prefix checks fail, the driver logs Bad stream spec: (with empty value) and returns false. The loop repeats forever, no way out short of restarting the process.

How to reproduce

Trigger any event that causes Read() to fail and call Disconnect(). Just reboot the fixposition device. The next recv() returns ECONNRESET, the worker calls Disconnect(), and from that point on the log fills with:

[WARN] read/recv fail: Connection reset by peer (104, ECONNRESET)
[INFO] Disconnecting from tcpcli://10.42.0.109:21000
[INFO] Reconnecting in 5.0 seconds...
[WARN] Bad stream spec:
[INFO] Reconnecting in 5.0 seconds...
[WARN] Bad stream spec:
... forever