init

Author: egmkang

.gitignore

@@ -2,6 +2,7 @@
 __pycache__/
 *.py[cod]
 *$py.class
+test.py
 
 # C extensions
 *.so
@@ -99,3 +100,4 @@ ENV/
 
 # mypy
 .mypy_cache/
+.idea/

README.md

@@ -0,0 +1,17 @@
+This `Pool` is very simple, you can use it as usual.
+```
+def create_conn():
+    return pymysql.connect(host=mysql_host, port=mysql_port, 
+                    user=mysql_user, password=mysql_password,
+                    database=mysql_db, charset='utf8',
+                    autocommit=True)
+pool = pymysqlpool.Pool(create_instance=create_conn)
+
+conn = pool.get()
+cur = conn.cursor()
+cur.execute("select 1")
+for x in cur:
+    pass
+cur.close()
+conn.close()
+```

pymysqlpool.py

@@ -0,0 +1,61 @@
+import threading
+import pymysql
+
+
+def new_close(conn):
+    if conn.pooling != None:
+        conn.pooling.put(conn)
+    elif conn.old_close != None:
+        conn.old_close()
+
+class Pool(object):
+    def __init__(self, create_instance, max_count=10, timeout=10):
+        self.lock = threading.Lock()
+        self.condition = threading.Condition(self.lock)
+        self.in_use_list = set()
+        self.free_list = set()
+        self.max_count = max_count or 10
+        self.timeout = timeout or 10
+        self.new_instance = create_instance
+        assert (create_instance != None)
+        self.__change_pymysql_close()
+
+    def __change_pymysql_close(self):
+        old_close = pymysql.connections.Connection.close
+        if old_close == new_close:
+            return
+        pymysql.connections.Connection.close = new_close
+        pymysql.connections.Connection.old_close = old_close
+
+    def get(self):
+        """get one from free list"""
+        with self.lock:
+            if len(self.free_list) > 0:
+                one = self.free_list.pop()
+                self.in_use_list.add(one)
+                return one
+            if len(self.in_use_list) < self.max_count:
+                one = self.new_instance()
+                one.pooling = self
+                self.free_list.add(one)
+            if len(self.free_list) <= 0:
+                self.condition.wait(self.timeout)
+                if len(self.free_list) <= 0:
+                    raise TimeoutError()
+            one = self.free_list.pop()
+            self.in_use_list.add(one)
+            return one
+
+    def put(self, value):
+        """put one into free list"""
+        with self.lock:
+            self.in_use_list.remove(value)
+            self.free_list.add(value)
+            self.condition.notify_all()
+
+    def size(self):
+        with self.lock:
+            return len(self.free_list) + len(self.in_use_list)
+
+    def max_size(self):
+        return self.max_count

test.py

@@ -0,0 +1,32 @@
+import pymysql
+import pymysqlpool
+
+mysql_host = '192.168.16.102'
+mysql_port = 3306
+mysql_user = 'root'
+mysql_password = '111'
+mysql_db = 'db'
+
+def create_conn():
+    return pymysql.connect(host=mysql_host, port=mysql_port, user=mysql_user, password=mysql_password, database=mysql_db,
+                    charset='utf8', autocommit=True)
+
+
+pool = pymysqlpool.Pool(create_instance=create_conn)
+
+conn = pool.get()
+cur = conn.cursor()
+cur.execute("select 1")
+for x in cur:
+    print(x)
+
+for x in range(20):
+    conn = pool.get()
+    print(x)
+    if x % 2 == 0:
+        conn.close()
+
+
+cur.close()
+conn.close()
+pass