Screen/tmux is not needed

[lzap]

Hey, stumbled upon your scripts. Nice, however tmux is not needed at all, systemd can create FIFO for STDIN:

# cat /etc/systemd/system/minecraft@.service
[Unit]
Description=Minecraft Bedrock: %i
After=network.target

[Service]
Sockets=minecraft@%i.socket
WorkingDirectory=/opt/minecraft/bedrock/%i
User=minecraft
Group=minecraft
ProtectHome=true
Type=simple
ExecStart=/opt/minecraft/bin/start-mc
ExecStop=/usr/bin/sh -c "echo 'say Server shutdown in 5 seconds' >/run/minecraft@%i/stdin"
ExecStop=/usr/bin/sleep 5
ExecStop=/usr/bin/sh -c "echo stop >/run/minecraft@%i/stdin"
TimeoutStopSec=30
Restart=always
RestartSec=600s
StandardInput=socket
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

# cat /etc/systemd/system/minecraft@.socket
[Unit]
BindsTo=minecraft@%i.service

[Socket]
RuntimeDirectory=%N
ListenFIFO=%t/%N/stdin
FileDescriptorName=control
RemoveOnStop=true
SocketMode=0660
SocketUser=minecraft
SocketGroup=minecraft

# echo "say HELLO WITHOUT TMUX" >/run/minecraft@survival_easy1/stdin

This is much more secure, I am working on implementing SELinux policy on top of that. With tmux that is not possible. FYI if you want to simplify your scripts a bit.

[TapeWerm]

Interesting, I will try that later. That could get rid of server_do(). The jank that is server_read() would live on albeit scraping journalctl instead of tmux. I wonder if journalctl can automatically parse the join/leave messages and push to the IRC bot and any future web hooks I've considered adding (likely just a line of wget). That would make the jank that is MCBElog.sh unneeded with up to 1 minute less delay as it would read on push instead of scraping once a minute. Only possible downside is while tmux confuses people having to use journalctl to see the output of a command echo'd to the pipe is also going to confuse some users.

Edit: I'm definitely putting the instance name in the description later. That was an oversight of mine, thank you.

[TapeWerm]

I addressed the description lacking instance name, I'll play with a separate branch trying systemd sockets later this weekend. Gotta apply for classes, read backup logs, and other stuff first.

[TapeWerm]

Branch werm_socket has some progress on scraping logs the same way I use tmux capture-pane. I'll work on it more tonight probably.
Edit: Most probable result of this is I drop tmux from the server and drop support for tmux sessions entirely. For now the IRC bot will stay in a tmux session.

[TapeWerm]

I'm having a lot of trouble getting input logged the way tmux did. I just want standard in to be logged in the journal but I haven't found anything in systemd or Bash for that.
Edit: I'm gonna have to hold off on this, just spent a few hours and made zero progress. Got other things that need to be done before tomorrow morning, unless someone finds out how to take standard in and put that in the journal or in standard output which does go to the journal.
Edit 2: ExecStart=/bin/bash -c 'tee | LD_LIBRARY_PATH=. ./bedrock_server' does not output the input in journalctl.
Edit 3: Alt plan could be the reason I need stdin in logs is I scrape journalctl and use what I put in stdin as a cutoff point for parsing it. I could use journalctl timestamps and parse those and compare dates to find such. Honestly might be a better system but would need a big rewrite to the backup scripts.
Edit 4: I fixed the backup script with a major refactor, testing and an update should be out soon.

[TapeWerm]

Latest 2 commits fix this issue. My services and scripts now use systemd sockets and journalctl. I may readd tmux compatibility later but that is irrelevant to this issue, the services will continue to use systemd sockets.

[lzap]

Wow that was fast, sorry I had bunch of github notifications to read through. This is cool.

# Thanks for sockets Lukáš Zapletal

This is not really necessary, it only pollutes such a nice and clean (tmux-free) config file now :-)

I am planning an article for opensource.com about SELinux policy and this repo will be totally featured as the recommended way! Kudos.