api: Add snowmix reconnects, make it shutdown gracefully

api/Dockerfile

@@ -20,4 +20,6 @@ ENV LC_ALL C.UTF-8
 ENV FLASK_APP apiserver.py
 ENV FLASK_ENV production
 
-CMD python3 -u apiserver.py
+STOPSIGNAL SIGKILL
+
+CMD [ "/usr/bin/python3", "-u", "apiserver.py" ]

api/snowmix.py

@@ -28,11 +28,16 @@ def cast(l, t, kl, default=None):
     return l
 
 class SnowmixClient(object):
+    reconnect = True
+
     def __init__(self, host='127.0.0.1', port=9999):
         self.connect(host, port)
         self.sem = threading.Semaphore()
 
     def connect(self, host, port):
+        self.host = host
+        self.port = port
+
         self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self.sock.settimeout(1.0)
         self.sock.connect((host, port))
@@ -52,13 +57,23 @@ class SnowmixClient(object):
 
     def call(self, command, expect='MSG:'):
         with self.sem:
-            self.flush_input()
+            try:
+                self.flush_input()
+
+                self.fd.write(command + '\r\n')
+                self.fd.flush()
+            except socket.error:
+                if self.reconnect:
+                    self.connect(self.host, self.port)
+
+                raise
 
-            self.fd.write(command + '\r\n')
-            self.fd.flush()
             while True:
                 line = self.fd.readline()
 
+                if not line:
+                    raise Exception('Remote host closed socket')
+
                 if expect and line.startswith(expect):
                     line = line[len(expect):].strip()
                     if not line: