Add a new example

examples/sanic_aiomysql_with_global_pool.py

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+# encoding: utf-8
+"""
+You need the aiomysql
+"""
+import asyncio
+import os
+
+import aiomysql
+import uvloop
+from sanic import Sanic
+from sanic.response import json
+
+database_name = os.environ['DATABASE_NAME']
+database_host = os.environ['DATABASE_HOST']
+database_user = os.environ['DATABASE_USER']
+database_password = os.environ['DATABASE_PASSWORD']
+app = Sanic()
+asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())
+
+
+async def get_pool(*args, **kwargs):
+    """
+    the first param in *args is the global instance ,
+    so we can store our connection pool in it .
+    and it can be used by different request
+    :param args:
+    :param kwargs:
+    :return:
+    """
+    args[0].pool = {
+        "aiomysql": await aiomysql.create_pool(host=database_host, user=database_user, password=database_password,
+                                               db=database_name,
+                                               maxsize=5)}
+    async with args[0].pool['aiomysql'].acquire() as conn:
+        async with conn.cursor() as cur:
+            await cur.execute('DROP TABLE IF EXISTS sanic_polls')
+            await cur.execute("""CREATE TABLE sanic_polls (
+                                    id serial primary key,
+                                    question varchar(50),
+                                    pub_date timestamp
+                                );""")
+            for i in range(0, 100):
+                await cur.execute("""INSERT INTO sanic_polls
+                                (id, question, pub_date) VALUES ({}, {}, now())
+                """.format(i, i))
+
+
+@app.route("/")
+async def test():
+    result = []
+    data = {}
+    async with app.pool['aiomysql'].acquire() as conn:
+        async with conn.cursor() as cur:
+            await cur.execute("SELECT question, pub_date FROM sanic_polls")
+            async for row in cur:
+                result.append({"question": row[0], "pub_date": row[1]})
+    if result or len(result) > 0:
+        data['data'] = res
+    return json(data)
+
+
+if __name__ == '__main__':
+    app.run(host="127.0.0.1", workers=4, port=12000, before_start=get_pool)