Add message of the day feature

5 files changed, 145 insertions, 30 deletions

diff --git a/README.md b/README.md
index 7d3ee28..52ea73e 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 MCSERVER-WRAPPER
 ================
 Minecraft server wrapper written in Python3 that extracts server status and list
-of online players.
+of online players and more.
 
 Requires:
 -----------------
@@ -34,11 +34,16 @@ positional arguments:
   command             Command to be executed to start Minecraft server.
 
 optional arguments:
-  -h, --help          show this help message and exit
-  --verbose, -v       Increase verbose level of output
-  --quiet, -q         Decrease verbose level of output
-  --status-file, -s   Outputs server status to file "status"
-  --players-file, -p  Outputs list of online players to file "players"
+  -h, --help            show this help message and exit
+  --verbose, -v         Increase verbose level of output
+  --quiet, -q           Decrease verbose level of output
+  --status-file, -s     Outputs server status to file "status"
+  --players-file, -p    Outputs list of online players to file "players"
+  --mod-file MOD_FILE, -m MOD_FILE
+                        Prints periodically random line from given file as
+                        message of the day.
+  --mod-time MOD_TIME   Period used for message of the day in seconds. In
+                        default 900 (15 minutes).
 ```
 
 ### How it works
@@ -74,8 +79,11 @@ This file in in status directory and is named as `players`. If server is running
 it contains online players. Player name per line.  If server isn't running, it
 content don't have to be valid.
 
-MCWRAPPER-TERMINAL
-------------------
-This application is going to be used for interactive terminal access to minecraft
-server console. It should use latest minecraft server log as input and output will
-be pushed to input pipe of mcwrapper.  This app is currently in development.
+### Message of the day
+This prints to players various short messages in given interval. Message is from
+file passed as --mod-file and it's randomly selected line. This file is read on
+wrapper start, so if you edit it while it's running, no change will happen unless
+you send USR1 signal to mcwrapper server. You can use this simple script:
+```
+[ -f server.pid ] && kill -USR1 $(cat server.pid)
+```
diff --git a/mcwrapper/__init__.py b/mcwrapper/__init__.py
index 2ae3c2a..dec7194 100755
--- a/mcwrapper/__init__.py
+++ b/mcwrapper/__init__.py
@@ -1,28 +1,27 @@
 # vim: expandtab ft=python ts=4 sw=4 sts=4:
-import os
-import sys
-import subprocess
 import signal
-import time
 import atexit
 import argparse
-from threading import Thread
 
 from . import prints
-from . import wrapper
+from . import alarm
 from .wrapper import MCWrapper
+from .mod import MoD
 
 mcserver_wrapper = None
+mcserver_mod = None
 
 
 def __wrapper_atexit__():
     "This is called when wrapper is exiting"
-    mcserver_wrapper.clean()
+    if mcserver_wrapper is not None:
+        mcserver_wrapper.clean()
 
 
 def __wrapper_toexit__():
     "This function is called when system signalizes that mcwrapper should exit"
-    mcserver_wrapper.stop()
+    if mcserver_wrapper is not None:
+        mcserver_wrapper.stop()
 
 
 def __signal_term__(_signo, _stack_frame):
@@ -36,6 +35,12 @@ __HELP_DESC__ = """
     """
 
 
+def reload():
+    "Reloads input files. Currently applicable only on mod."
+    if mcserver_mod is not None:
+        mcserver_mod.load_mods()
+
+
 def main():
     "Main function"
     global verbose_level
@@ -49,6 +54,12 @@ def main():
     parser.add_argument('--players-file', '-p', action='store_true',
                         help="""Outputs list of online players to file
                         \"players\" """)
+    parser.add_argument('--mod-file', '-m', type=str,
+                        help="""Prints periodically random line from
+                        given file as message of the day.""")
+    parser.add_argument('--mod-time', type=int,
+                        help="""Period used for message of the day in
+                        seconds. In default 900 (15 minutes).""")
     parser.add_argument('command', nargs=argparse.REMAINDER,
                         help="""Command to be executed to start Minecraft
                         server.""")
@@ -58,20 +69,31 @@ def main():
     command = args.command
     sfile = args.status_file
     pfile = args.players_file
+    mod_file = args.mod_file
+    mod_time = args.mod_time
 
     if not command:
         parser.print_help()
         return
+    # Just small hack to not open minecraft server gui
     if 'nogui' not in command:
         command.append('nogui')
 
+    alarm.init()
+    signal.signal(signal.SIGUSR1, reload)
+    signal.signal(signal.SIGUSR2, reload)  # probably can be used for something else in future
+
     global mcserver_wrapper
     mcserver_wrapper = MCWrapper(command, pfile, sfile)
     signal.signal(signal.SIGTERM, __signal_term__)
     signal.signal(signal.SIGINT, __signal_term__)
     atexit.register(__wrapper_atexit__)
 
-    mcserver_wrapper.execstart()
+    mcserver_wrapper.start()
+    if mod_file is not None:
+        global mcserver_mod
+        mcserver_mod = MoD(mcserver_wrapper, mod_file, mod_time or 900)
+    mcserver_wrapper.process.wait()
 
 if __name__ == '__main__':
     main()
diff --git a/mcwrapper/alarm.py b/mcwrapper/alarm.py
new file mode 100644
index 0000000..de61741
--- /dev/null
+++ b/mcwrapper/alarm.py
@@ -0,0 +1,66 @@
+# vim: expandtab ft=python ts=4 sw=4 sts=4:
+import signal
+import time
+
+# Dict with alarms. Alarm is dictionary with initial time, alarm time and
+# handler
+__alarms__ = dict()
+__alarm_wait__ = None
+
+
+def __handler__(signum, frame):
+    if __alarm_wait__["arg"] is not None:
+        __alarm_wait__["handler"](__alarm_wait__["arg"])
+    else:
+        __alarm_wait__["handler"]()
+    if not __alarm_wait__["repeat"]:
+        __alarms__.pop(__alarm_wait__["name"])
+    else:
+        __alarm_wait__["time"] = __alarm_wait__["time"] + \
+            __alarm_wait__["timeout"]
+    __update__()
+
+
+def __update__():
+    lowest = None
+    lowest_time = None
+    now = time.time()
+    for name, al in __alarms__.items():
+        t = al["time"] + al["timeout"] - now
+        if lowest_time is None or lowest_time > t:
+            lowest_time = t
+            lowest = al
+    global __alarm_wait__
+    if lowest is not None:
+        if lowest_time < 1:
+            # Less then second is missed alarm. Fire handler.
+            __alarm_wait__ = lowest
+            __handler__(None, None)
+            return
+        __alarm_wait__ = lowest
+        signal.alarm(int(lowest_time))
+    elif __alarm_wait__ is not None:
+        signal.alarm(0)  # close any alarm
+        __alarm_wait__ = None
+
+
+def init():
+    signal.signal(signal.SIGALRM, __handler__)  # prepare alarm
+
+
+def set(name, t, handler, repeat=False, arg=None):
+    al = dict()
+    al["time"] = time.time()
+    al["handler"] = handler
+    al["timeout"] = t
+    al["repeat"] = repeat
+    al["arg"] = arg
+    al["name"] = name
+    __alarms__[name] = al
+    __update__()
+
+
+def unset(name):
+    if name in __update__:
+        __alarms__.pop(name)
+        __update__()
diff --git a/mcwrapper/mod.py b/mcwrapper/mod.py
new file mode 100644
index 0000000..78ffb8e
--- /dev/null
+++ b/mcwrapper/mod.py
@@ -0,0 +1,24 @@
+# vim: expandtab ft=python ts=4 sw=4 sts=4:
+import random
+
+from . import alarm
+
+
+class MoD:
+    "Message of the day handler"
+    def __init__(self, mcwrapper, file, period=900):
+        self.mcwrapper = mcwrapper
+        self.file = file
+        self.load_mods()
+        alarm.set("mod-time", period, self.__handler__, repeat=True)
+
+    def load_mods(self):
+        "Loads messages from self.file"
+        with open(self.file, "r") as f:
+            self.lines = f.readlines()
+
+    def __handler__(self):
+        if len(self.lines) > 0:
+            i = random.randint(0, len(self.lines) - 1)
+            self.mcwrapper.write_to_terminal("/say " + self.lines[i].rstrip()
+                                             + "\n")
diff --git a/mcwrapper/wrapper.py b/mcwrapper/wrapper.py
index 1896266..3e9a0d7 100644
--- a/mcwrapper/wrapper.py
+++ b/mcwrapper/wrapper.py
@@ -36,11 +36,11 @@ class MCWrapper:
             try:
                 os.kill(lpid, 0)
             except OSError:
-                prints.warning("Detected forced termination of previous server "
-                        "wrapper instance.")
+                prints.warning("Detected forced termination of previous server"
+                               " wrapper instance.")
             else:
-                prints.error("Another wrapper is running with given identifier.",
-                      -1, 1)
+                prints.error("Another wrapper is running with given "
+                             "identifier.", -1, 1)
         try:
             os.mkfifo(__INPUTPIPE__, 0o640)
         except FileExistsError:
@@ -75,11 +75,6 @@ class MCWrapper:
         except FileNotFoundError:
             pass
 
-    def execstart(self):
-        "Start execution of Minecraft server and hold until its exits"
-        self.start()
-        self.process.wait()
-
     def start(self):
         "Start Minecraft server"
         self.process = subprocess.Popen(
@@ -111,7 +106,7 @@ class MCWrapper:
     def write_to_terminal(self, text):
         "Write to server terminal. If server not running it does nothing"
         if self.status == 2:
-            prints.info("Input: " + text, 1)
+            prints.info("Input: " + text.rstrip(), 1)
             self.process.stdin.write(bytes(text, sys.getdefaultencoding()))
             self.process.stdin.flush()
             return True