Making list length fetching support globs

Making each configured instance have its own class to avoid global variables

README.md

@@ -13,6 +13,7 @@ You can capture any kind of Redis metrics like:
  * Uptime
  * Changes since last save
  * Replication delay (per slave)
+ * The length of list values
 
 
 Installation and Configuration

redis_client.py

@@ -0,0 +1,64 @@
+import socket
+
+class RedisClient():
+    def __init__(self, host, port, auth):
+        self.host = host
+        self.port = port
+        self.auth = auth
+
+    def connect(self):
+        self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.socket.connect((self.host, self.port))
+
+        self.file = self.socket.makefile('r')
+
+        if self.auth is not None:
+            self.send('auth %s' % (self.auth))
+
+            self.read_response()
+
+    def __enter__(self):
+        self.connect()
+        return self
+
+    def __exit__(self, *args):
+        if self.socket:
+            self.socket.close()
+
+    def send(self, message):
+        return self.socket.sendall("%s\r\n" % message)
+
+    def read_response(self):
+        first_line = self.file.readline()
+        if first_line.startswith('-'):
+            raise RedisError(first_line)
+
+        if first_line.startswith('*'):
+            return self.read_array(first_line)
+        elif first_line.startswith('$'):
+            return self.read_bulk_string(first_line)
+        elif first_line.startswith(':'):
+            return first_line.lstrip(':').rstrip()
+        elif first_line.startswith('+'):
+            return first_line.lstrip('+').rstrip()
+        else:
+            raise ValueError("Unknown Redis response: %s" % first_line)
+
+    def read_array(self, first_line):
+        size = int(first_line.lstrip("*").rstrip())
+        return [self.read_response() for i in range(0, size)]
+
+    def read_bulk_string(self, first_line):
+        size = int(first_line.lstrip("$").rstrip())
+        if size == -1:
+            return None
+
+        s = self.file.read(size)
+        # Get rid of \r\n at end
+        self.file.read(2)
+
+        return s
+
+
+class RedisError(Exception):
+    pass