This is a quick start document that targets people without prior experience with Redis. Reading this document will help you:
- Download and compile Redis to start hacking.
- Use redis-cli to access the server.
- Use Redis from your application.
- Understand how Redis persistence works.
- Install Redis more properly.
- Find out what to read next to understand more about Redis.
The suggested way of installing Redis is compiling it from sources as Redis has no dependencies other than a working GCC compiler and libc. Installing it using the package manager of your Linux distribution is somewhat discouraged as usually the available version is not the latest.
- Feb 28, 2020 Updated on February 28th, 2020 in #docker, #flask. Dockerize a Flask, Celery, and Redis Application with Docker Compose Learn how to install and use Docker to run a multi-service Flask, Celery and Redis application in development with Docker Compose.
- Cloud native images. Install GitLab with Docker. Docker and container technology have been revolutionizing the software world for the past few years. They combine the performance and efficiency of native execution with the abstraction, security, and immutability of virtualization.
- While designed for web development, the PHP scripting language also provides general-purpose use.
You can either download the latest Redis tar ball from the redis.io web site, or you can alternatively use this special URL that always points to the latest stable Redis version, that is, http://download.redis.io/redis-stable.tar.gz.
.Redis Quick Start. This is a quick start document that targets people without prior experience with Redis. Reading this document will help you: Download and compile Redis to start hacking. Use redis-cli to access the server. Use Redis from your application. Understand how Redis persistence works. Install Redis more properly. This tutorial shows how to install RedisInsight on Docker so you can use RedisInsight in development. We have a separate guide for installing RedisInsight on AWS. The first step is to install docker for your operating system. Run the docker version command in a terminal window to make sure that docker is installed correctly.
In order to compile Redis follow these simple steps:
At this point you can test if your build has worked correctly by typing make test, but this is an optional step. After compilation the src directory inside the Redis distribution is populated with the different executables that are part of Redis:
- redis-server is the Redis Server itself.
- redis-sentinel is the Redis Sentinel executable (monitoring and failover).
- redis-cli is the command line interface utility to talk with Redis.
- redis-benchmark is used to check Redis performances.
- redis-check-aof and redis-check-rdb (redis-check-dump in 3.0 and below) are useful in the rare event of corrupted data files.
It is a good idea to copy both the Redis server and the command line interface into the proper places, either manually using the following commands:
- sudo cp src/redis-server /usr/local/bin/
- sudo cp src/redis-cli /usr/local/bin/
Or just using sudo make install
.
In the following documentation we assume that /usr/local/bin is in your PATH environment variable so that you can execute both the binaries without specifying the full path.
The simplest way to start the Redis server is just executing the redis-server binary without any argument.
In the above example Redis was started without any explicit configuration file, so all the parameters will use the internal default. This is perfectly fine if you are starting Redis just to play a bit with it or for development, but for production environments you should use a configuration file.
In order to start Redis with a configuration file use the full path of the configuration file as first argument, like in the following example: redis-server /etc/redis.conf. You should use the redis.conf
file included in the root directory of the Redis source code distribution as a template to write your configuration file.
External programs talk to Redis using a TCP socket and a Redis specific protocol. This protocol is implemented in the Redis client libraries for the different programming languages. However to make hacking with Redis simpler Redis provides a command line utility that can be used to send commands to Redis. This program is called redis-cli.
The first thing to do in order to check if Redis is working properly is sending a PING command using redis-cli:
Running redis-cli followed by a command name and its arguments will send this command to the Redis instance running on localhost at port 6379. You can change the host and port used by redis-cli, just try the --help option to check the usage information.
Another interesting way to run redis-cli is without arguments: the program will start in interactive mode, you can type different commands and see their replies.
Docker Install Redis
At this point you are able to talk with Redis. It is the right time to pause a bit with this tutorial and start the fifteen minutes introduction to Redis data types in order to learn a few Redis commands. Otherwise if you already know a few basic Redis commands you can keep reading.
By default Redis binds to all the interfaces and has no authentication at all. If you use Redis in a very controlled environment, separated from the external internet and in general from attackers, that's fine. However if Redis without any hardening is exposed to the internet, it is a big security concern. If you are not 100% sure your environment is secured properly, please check the following steps in order to make Redis more secure, which are enlisted in order of increased security.
- Make sure the port Redis uses to listen for connections (by default 6379 and additionally 16379 if you run Redis in cluster mode, plus 26379 for Sentinel) is firewalled, so that it is not possible to contact Redis from the outside world.
- Use a configuration file where the
bind
directive is set in order to guarantee that Redis listens on only the network interfaces you are using. For example only the loopback interface (127.0.0.1) if you are accessing Redis just locally from the same computer, and so forth. - Use the
requirepass
option in order to add an additional layer of security so that clients will require to authenticate using the AUTH command. - Use spiped or another SSL tunneling software in order to encrypt traffic between Redis servers and Redis clients if your environment requires encryption.
Note that a Redis exposed to the internet without any security is very simple to exploit, so make sure you understand the above and apply at least a firewalling layer. After the firewalling is in place, try to connect with redis-cli
from an external host in order to prove yourself the instance is actually not reachable.
Of course using Redis just from the command line interface is not enough as the goal is to use it from your application. In order to do so you need to download and install a Redis client library for your programming language. You'll find a full list of clients for different languages in this page.
For instance if you happen to use the Ruby programming language our best advice is to use the Redis-rb client. You can install it using the command gem install redis.
These instructions are Ruby specific but actually many library clients for popular languages look quite similar: you create a Redis object and execute commands calling methods. A short interactive example using Ruby:
You can learn how Redis persistence works on this page, however what is important to understand for a quick start is that by default, if you start Redis with the default configuration, Redis will spontaneously save the dataset only from time to time (for instance after at least five minutes if you have at least 100 changes in your data), so if you want your database to persist and be reloaded after a restart make sure to call the SAVE command manually every time you want to force a data set snapshot. Otherwise make sure to shutdown the database using the SHUTDOWN command:
This way Redis will make sure to save the data on disk before quitting. Reading the persistence page is strongly suggested in order to better understand how Redis persistence works.
Running Redis from the command line is fine just to hack a bit with it or for development. However at some point you'll have some actual application to run on a real server. For this kind of usage you have two different choices:
- Run Redis using screen.
- Install Redis in your Linux box in a proper way using an init script, so that after a restart everything will start again properly.
A proper install using an init script is strongly suggested. The following instructions can be used to perform a proper installation using the init script shipped with Redis 2.4 in a Debian or Ubuntu based distribution.
We assume you already copied redis-server and redis-cli executables under /usr/local/bin.
Create a directory in which to store your Redis config files and your data:
Copy the init script that you'll find in the Redis distribution under the utils directory into /etc/init.d. We suggest calling it with the name of the port where you are running this instance of Redis. For example:
Edit the init script.
Make sure to modify REDISPORT accordingly to the port you are using. Both the pid file path and the configuration file name depend on the port number.
Copy the template configuration file you'll find in the root directory of the Redis distribution into /etc/redis/ using the port number as name, for instance:
Create a directory inside /var/redis that will work as data and working directory for this Redis instance:
Edit the configuration file, making sure to perform the following changes:
- Set daemonize to yes (by default it is set to no).
- Set the pidfile to
/var/run/redis_6379.pid
(modify the port if needed). - Change the port accordingly. In our example it is not needed as the default port is already 6379.
- Set your preferred loglevel.
- Set the logfile to
/var/log/redis_6379.log
- Set the dir to /var/redis/6379 (very important step!)
Finally add the new Redis init script to all the default runlevels using the following command:
You are done! Now you can try running your instance with:
Make sure that everything is working as expected:
- Try pinging your instance with redis-cli.
- Do a test save with redis-cli save and check that the dump file is correctly stored into /var/redis/6379/ (you should find a file called dump.rdb).
- Check that your Redis instance is correctly logging in the log file.
- If it's a new machine where you can try it without problems make sure that after a reboot everything is still working.
Note: In the above instructions we skipped many Redis configuration parameters that you would like to change, for instance in order to use AOF persistence instead of RDB persistence, or to setup replication, and so forth. Make sure to read the example redis.conf
file (that is heavily commented) and the other documentation you can find in this web site for more information.
Redis and Express are tools that provide a simple and clean approach to their problem domains. What follows is a Docker/Docker Compose v2 setup.
The repo is available at: https://github.com/HugoDF/express-redis-docker.
The docker-compose.yml
is available at: github.com/HugoDF/express-redis-docker/docker-compose.yml
Redis is “an open source, in-memory data structure store, used as a database, cache and message broker”. It’s as simple and unopinionated as a database as it gets, it’s known for its performance and simplicity as a key-value store. It has great flexibility and can also be used as a message queue, circular buffer (and pretty much anything else a developer can come up with short of a relational database).
Express is a “fast, unopinionated, minimalist web framework for Node.js”. In other words, it’s a wrapper around Node’s server, that provides a way to write what’s called “middleware” to share and compose functionality across HTTP endpoints as well as define said endpoints.
Getting Redis and Express to work together is trivial. Getting Redis and Express to work together in a way that’s fool and future-proof, and reproducible across local and deployed environments, is slightly harder. That’s where Docker and Docker Compose come in.
Docker is a containerisation system, Docker Compose is a way to define how multiple Docker containers interact. In the context of Node web application development, Docker tends to be used to define a container that has the required system-level dependencies (eg. Node version, any extra database drivers). Docker Compose would be used to define dependencies outside of the Node application, for example databases.
To start off, we should create a new directory/initialise npm:
We can then install Express:
And create a server.js
file that looks like the following:
That can be run using:
We can check that it’s working as expected
To begin you’ll want to install Docker Community Edition (https://www.docker.com/community-edition).Then we can add a Dockerfile
and a docker-compose.yml
:
Now run the app inside of Docker/Docker Compose:
And check that it still works
Some extra context:
Docker Install Redis Server
- The
Dockerfile
defines what container the application will be running in (here a Node 10 default container) docker-compose.yml
:build
explains which image should be used by theapp
service definition (in this case, it points to what would be created by running theDockerfile
)volumes
defines what should be mounted where (in this case, we’ll mount the whole directory as/var/www/app
ports
maps ports from the host system to ports inside the containerenvironment
sets environment variables for the containercommand
determines what will be run on startup of the container, here it runsnpm install
followed by the server startup command
To add Redis to our Express app we should use the redis
package:
Then we should probably wrap all the callback-based methods we want to use (see the api docs for the redis package, https://github.com/NodeRedis/node_redis#api).Let’s do this using a redis-client.js
module:
To running Redis inside of Docker Compose in such a way that our app can access it:
We can now access the Redis client from the app container:
We can now create a HTTP API that will allow us to store data using query params and retrieve them using a get request (this isn’t RESTful at all but oh well 🙂 ).
If you have any questions about the above code let me know @hugo__df. It is using a couple of more advanced features like async/await and destructuring as well as Express features to get query and path parameters (see https://expressjs.com/en/api.html#req.query, https://expressjs.com/en/api.html#req.params).
Get the app running again: docker-compose up
- Store some data:
- Retrieve that data:
Note to more advanced Express users, and API design gurus.The reason I used an old school query-param based system is to avoid the boilerplate of using body-parser
with POST requests
Full repository available at: https://github.com/HugoDF/express-redis-docker
Cover photo by Ben Koorengevel on Unsplash
Docker Install Redis
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