Adding artifacts for tutorials.

Author: triggan

database-caching/.DS_Store

@@ -0,0 +1,30 @@
+This code is part of an Amazon ElastiCache Tutorial
+
+
+1. Install dependencies:
+
+    $ pip3 install -r requirements.txt
+
+
+2. Populate the database:
+
+    $ mysql -h endpoint -P 3306 -u admin -p < seed.sql
+
+
+3.  Configure environment
+
+    $ export REDIS_URL=redis://redis_endpoint:6379/
+    $ export DB_HOST=mysql_endpoint
+    $ export DB_USER=admin
+    $ export DB_PASS=password
+    $ export DB_NAME=tutorial
+
+
+    Note that you have to supply the real values for `redis_endpoint`,
+    `mysql_endpoint`, and `password`.
+
+
+4.  Run the example:
+
+    $ python example.py
+

database-caching/INSTALL

@@ -29,8 +29,8 @@ $ sudo yum install git -y
 $ sudo yum install mysql -y
 $ sudo yum install python3 -y
 $ pip3 install --user virtualenv
-$ git clone <repository-url>/elc-cache-aside
-$ cd elc-cache-aside
+$ git clone https://github.com/aws-samples/amazon-elasticache-samples/
+$ cd amazon-elasticache-samples/database-caching
 $ virtualenv venv
 $ source ./venv/bin/activate
 $ pip3 install -r requirements.txt
@@ -246,7 +246,7 @@ While the instances are being created, you will see a banner explaining how to o
 
 # Step 3: Populate your MySQL database
 
-You can populate the database with the seed.sql file provided in the tutorial repository. Log into your EC2 instance and run this command:
+You can populate the database with the [seed.sql](./seed.sql) file provided in the [tutorial repository](./). Log into your EC2 instance and run this command:
 
 **syntax: shell**
 
@@ -260,7 +260,7 @@ If the command hangs, chances are you are being blocked by the Security Group se
 
 In Source, you can start typing the name of the security group and you'll be able to click on the Security Group ID. If you need to learn more about Security Groups, you can check [the documentation](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_SecurityGroups.html) or the [Security Group Rules Reference](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/security-group-rules-reference.html).
 
-Below is a breakdown of the commands contained in the seed.sql file. If you succeeded in populating the database, you can skip the steps below and go directly to step 4.
+Below is a breakdown of the commands contained in the [seed.sql](./seed.sql) file. If you succeeded in populating the database, you can skip the steps below and go directly to step 4.
 
 ### 3.1 — Connect to your database:
 
@@ -282,7 +282,7 @@ mysql> CREATE database tutorial;
 Query OK, 1 row affected (0.01 sec)
 ```
 
-At this point you can use the tutorial database,  create tables and add some records.
+At this point you can use the tutorial database, create tables and add some records.
 
 **syntax: SQL**
 
@@ -387,7 +387,7 @@ In Source, you can start typing the name of the security group and you'll be abl
 
 ## Configure the environment
 
-In the repository you will find some Python code that you can run in your EC2 instance. But first you need to configure some environment variables:
+In the [repository](./) you will find some [Python code](./example.py) that you can run in your EC2 instance. But first you need to configure some environment variables:
 
 **syntax: shell**
 

database-caching/README.md

@@ -0,0 +1,79 @@
+import os
+import json
+
+import redis
+import pymysql
+
+
+class DB:
+    def __init__(self, **params):
+        params.setdefault("charset", "utf8mb4")
+        params.setdefault("cursorclass", pymysql.cursors.DictCursor)
+
+        self.mysql = pymysql.connect(**params)
+
+    def query(self, sql):
+        with self.mysql.cursor() as cursor:
+            cursor.execute(sql)
+            return cursor.fetchall()
+
+    def record(self, sql, values):
+        with self.mysql.cursor() as cursor:
+            cursor.execute(sql, values)
+            return cursor.fetchone()
+
+
+# Time to live for cached data
+TTL = 10
+
+# Read the Redis credentials from the REDIS_URL environment variable.
+REDIS_URL = os.environ.get('REDIS_URL')
+
+# Read the DB credentials from the DB_* environment variables.
+DB_HOST = os.environ.get('DB_HOST')
+DB_USER = os.environ.get('DB_USER')
+DB_PASS = os.environ.get('DB_PASS')
+DB_NAME = os.environ.get('DB_NAME')
+
+# Initialize the database
+Database = DB(host=DB_HOST, user=DB_USER, password=DB_PASS, db=DB_NAME)
+
+# Initialize the cache
+Cache = redis.Redis.from_url(REDIS_URL)
+
+
+def fetch(sql):
+    """Retrieve records from the cache, or else from the database."""
+    res = Cache.get(sql)
+
+    if res:
+        return json.loads(res)
+
+    res = Database.query(sql)
+    Cache.setex(sql, TTL, json.dumps(res))
+    return res
+
+
+def planet(id):
+    """Retrieve a record from the cache, or else from the database."""
+    key = f"planet:{id}"
+    res = Cache.hgetall(key)
+
+    if res:
+        return res
+
+    sql = "SELECT `id`, `name` FROM `planet` WHERE `id`=%s"
+    res = Database.record(sql, (id,))
+
+    if res:
+        Cache.hmset(key, res)
+        Cache.expire(key, TTL)
+
+    return res
+
+
+# Display the result of some queries
+print(fetch("SELECT * FROM planet"))
+print(planet(1))
+print(planet(2))
+print(planet(3))

database-caching/example.py

@@ -0,0 +1,2 @@
+PyMySQL==0.9.3
+redis==3.2.1

database-caching/requirements.txt

@@ -0,0 +1,14 @@
+CREATE database tutorial;
+USE tutorial;
+CREATE TABLE planet (
+  id INT UNSIGNED AUTO_INCREMENT,
+  name VARCHAR(30),
+  PRIMARY KEY(id));
+INSERT INTO planet (name) VALUES ("Mercury");
+INSERT INTO planet (name) VALUES ("Venus");
+INSERT INTO planet (name) VALUES ("Earth");
+INSERT INTO planet (name) VALUES ("Mars");
+INSERT INTO planet (name) VALUES ("Jupiter");
+INSERT INTO planet (name) VALUES ("Saturn");
+INSERT INTO planet (name) VALUES ("Uranus");
+INSERT INTO planet (name) VALUES ("Neptune");

database-caching/seed.sql

@@ -0,0 +1,23 @@
+This code is part of an Amazon ElastiCache Tutorial
+
+
+1. Install dependencies:
+
+    $ pip3 install -r requirements.txt
+
+
+2. Configure environment variables:
+
+    # Use the name of the example you want to run.
+    $ export FLASK_APP=example-1.py
+
+    # Replace the value with a random string.
+    $ export SECRET_KEY=some_secret_string
+
+    # Replace the hostname with the endpoint of your ElastiCache instance.
+    $ export REDIS_URL=redis://hostname:6379/
+
+
+3.  Start the server on port 5000:
+
+    $ flask run -h 0.0.0.0 -p 5000

session-store/.DS_Store

@@ -26,8 +26,8 @@ Once you have access to your EC2 instance, run the following commands:
 $ sudo yum install git
 $ sudo yum install python3
 $ sudo pip3 install virtualenv
-$ git clone https://github.com/aws-samples/amazon-elasticache-samples/session-store/
-$ cd session-store
+$ git clone https://github.com/aws-samples/amazon-elasticache-samples/
+$ cd amazon-elasticache-samples/session-store
 $ virtualenv venv
 $ source ./venv/bin/activate
 $ pip3 install -r requirements.txt

session-store/INSTALL

@@ -0,0 +1,37 @@
+import os
+
+from flask import Flask, session, redirect, escape, request
+
+
+# Configure the application name with the FLASK_APP environment variable.
+app = Flask(__name__)
+
+
+# Configure the secret_key with the SECRET_KEY environment variable.
+app.secret_key = os.environ.get('SECRET_KEY', default=None)
+
+
+@app.route('/')
+def index():
+    if 'username' in session:
+        return 'Logged in as %s' % escape(session['username'])
+    return 'You are not logged in'
+
+
+@app.route('/login', methods=['GET', 'POST'])
+def login():
+    if request.method == 'POST':
+        session['username'] = request.form['username']
+        return redirect('/')
+    return '''
+        <form method="post">
+        <p><input type=text name=username>
+        <p><input type=submit value=Login>
+        </form>
+    '''
+
+
+@app.route('/logout')
+def logout():
+    session.pop('username', None)
+    return redirect('/')