Add mcstatus library and only re/connect to server if it is online.

Pipfile

@@ -13,6 +13,7 @@ cryptography = "*"
 future = "*"
 "discord.py" = {git = "https://github.com/Rapptz/discord.py.git"}
 sqlalchemy = "*"
+mcstatus = "*"
 
 [requires]
 python_version = "3.6"

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "d86ac26059caa9dc880cea720fdbc3726de055c74589031e68afa03b55a0500c"
+            "sha256": "b74ed57bc94dedc5e0cb39283d2d16b952c17d6db29c6a0c51956b5607f54017"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -74,6 +74,13 @@
             ],
             "version": "==3.0.4"
         },
+        "click": {
+            "hashes": [
+                "sha256:2335065e6395b9e67ca716de5f7526736bfa6ceead690adf616d925bdc622b13",
+                "sha256:5b94b49521f6456670fdb30cd82a4eca9412788a93fa6dd6df72c94d5a8ff2d7"
+            ],
+            "version": "==7.0"
+        },
         "cryptography": {
             "hashes": [
                 "sha256:02602e1672b62e803e08617ec286041cc453e8d43f093a5f4162095506bc0beb",
@@ -102,6 +109,19 @@
         "discord.py": {
             "git": "https://github.com/Rapptz/discord.py.git"
         },
+        "dnspython": {
+            "hashes": [
+                "sha256:40f563e1f7a7b80dc5a4e76ad75c23da53d62f1e15e6e517293b04e1f84ead7c",
+                "sha256:861e6e58faa730f9845aaaa9c6c832851fbf89382ac52915a51f89c71accdd31"
+            ],
+            "version": "==1.15.0"
+        },
+        "dnspython3": {
+            "hashes": [
+                "sha256:6eb9504abafb91cb67ed9dc3d3289a3ccc438533b460eccbf77e36c5323100f4"
+            ],
+            "version": "==1.15.0"
+        },
         "future": {
             "hashes": [
                 "sha256:e39ced1ab767b5936646cedba8bcce582398233d6a627067d4c6a454c90cfedb"
@@ -116,6 +136,13 @@
             ],
             "version": "==2.7"
         },
+        "mcstatus": {
+            "hashes": [
+                "sha256:dc0e9fe79d8e3d4c7f3e218921b82b50ab31c991e88cb86831377bd5d2789c12"
+            ],
+            "index": "pypi",
+            "version": "==2.2"
+        },
         "minecraft": {
             "git": "https://github.com/ammaraskar/pyCraft.git"
         },

webhook-bridge.py

@@ -23,6 +23,8 @@ from minecraft.compat import input
 import discord
 import asyncio
 
+from mcstatus import MinecraftServer
+
 UUID_CACHE = {}
 
 def setup_logging(level):
@@ -47,12 +49,29 @@ def main():
     def handle_disconnect(join_game_packet):
         logging.info('Disconnected.')
         connection.disconnect(immediate=True)
+        while not is_server_online():
+            logging.info('Not reconnecting to server because it appears to be offline.')
             time.sleep(5)
         logging.info('Reconnecting.')
         connection.connect()
 
+    def is_server_online():
+        server = MinecraftServer.lookup("{}:{}".format(config.mc_server, config.mc_port))
+        try:
+            status = server.status()
+            del status
+            return True
+        except:
+            # The server is offline
+            return False
+
+    logging.debug("Checking if the server {} is online before connecting.")
+
     if not config.mc_online:
         logging.info("Connecting in offline mode...")
+        if not is_server_online():
+            logging.info('Not connecting to server because it appears to be offline.')
+            sys.exit(1)
         connection = Connection(
             config.mc_server, config.mc_port, username=config.mc_username,
             handle_exception=handle_disconnect)
@@ -64,6 +83,9 @@ def main():
             logging.info(e)
             sys.exit()
         logging.info("Logged in as %s..." % auth_token.username)
+        if not is_server_online():
+            logging.info('Not connecting to server because it appears to be offline.')
+            sys.exit(1)
         connection = Connection(
             config.mc_server, config.mc_port, auth_token=auth_token,
             handle_exception=handle_disconnect)