Squid Proxy Docker Image

• Introduction
  • Contributing
  • Issues
• Getting started
  • Installation
  • Quickstart
  • Command-line arguments
  • Persistence
  • Configuration
  • Usage
  • Logs
• Maintenance
  • Upgrading
  • Shell Access

Introduction

Dockerfile to create a Docker container image for Squid proxy server.

Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. It reduces bandwidth and improves response times by caching and reusing frequently-requested web pages. Squid has extensive access controls and makes a great server accelerator.

Contributing

If you find this image useful here's how you can help:

• Send a pull request with your awesome features and bug fixes
• Help users resolve their issues.

Issues

Before reporting your issue please try updating Docker to the latest version and check if it resolves the issue. Refer to the Docker installation guide for instructions.

If the above documentation does not help then report your issue along with the following information:

• Output of the docker version and docker info commands
• The docker run command or docker-compose.yml used to start the image. Mask out the sensitive bits.
• Please state if you are using Docker Desktop, VirtualBox, etc.

Getting started

Installation

Automated builds of the image are available on Dockerhub and is the recommended method of installation.

docker pull allir/squid:latest

Alternatively you can build the image yourself.

docker build -t squid github.com/allir/docker-squid

Quickstart

Start Squid using:

docker run --name squid -d --restart=always \
  --publish 3128:3128 \
  --volume /srv/docker/squid/cache:/var/spool/squid \
  allir/squid:latest

Alternatively, you can use the sample docker-compose.yml file to start the container using Docker Compose

Command-line arguments

You can customize the launch command of the Squid server by specifying arguments to squid on the docker run command. For example the following command prints the help menu of squid command:

docker run --name squid -it --rm \
  --publish 3128:3128 \
  --volume /srv/docker/squid/cache:/var/spool/squid \
  allir/squid:latest -h

Persistence

For the cache to preserve its state across container shutdown and startup you should mount a volume at /var/spool/squid.

The Quickstart command already mounts a volume for persistence.

SELinux users should update the security context of the host mountpoint so that it plays nicely with Docker:

mkdir -p /srv/docker/squid
chcon -Rt svirt_sandbox_file_t /srv/docker/squid

Configuration

Squid is a full featured caching proxy server and a large number of configuration parameters. To configure Squid as per your requirements mount your custom configuration at /etc/squid/squid.conf.

docker run --name squid -d --restart=always \
  --publish 3128:3128 \
  --volume /path/to/squid.conf:/etc/squid/squid.conf \
  --volume /srv/docker/squid/cache:/var/spool/squid \
  allir/squid:latest

To reload the Squid configuration on a running instance you can send the HUP signal to the container.

docker kill -s HUP squid

IMPORTANT NOTE: Some required configuration options are stored at /etc/squid/conf.d and need to be included in any custom config. These are needed so that the image can be run as a non root user.

To make sure these options are loaded add the following line to the configuration.

include /etc/squid/conf.d/*

Alternatively you can also add the required configuration options in your own config.

pid_filename /var/run/squid/squid.pid

logfile_rotate 0
cache_log stdio:/dev/null
access_log stdio:/dev/stdout
cache_store_log stdio:/dev/stdout

Usage

Configure your web browser network/connection settings to use the proxy server which is available at 172.17.0.1:3128

If you are using Linux then you can also add the following lines to your .bashrc file allowing command line applications to use the proxy server for outgoing connections.

export ftp_proxy=http://172.17.0.1:3128
export http_proxy=http://172.17.0.1:3128
export https_proxy=http://172.17.0.1:3128

To use Squid in your Docker containers add the following line to your Dockerfile.

ENV http_proxy=http://172.17.0.1:3128 \
    https_proxy=http://172.17.0.1:3128 \
    ftp_proxy=http://172.17.0.1:3128

Logs

The default configuration will log to stdout so the logs can be viewed via docker logs.

docker logs squid

Maintenance

Using the latest tag is discouraged for any production or stable usage so using a specific version is recommended, for example allir/squid:5.7.

Upgrading

Example process for updating between versions. If you are running for example 5.6 and want to update to 5.7:

To upgrade to newer releases:

1. Download the updated Docker image:

   docker pull allir/squid:5.7

2. Stop the currently running image:

   docker stop squid

3. Remove the stopped container

   docker rm -v squid

4. Start the updated image

   docker run -name squid -d \
     [OPTIONS] \
     allir/squid:5.7

Shell Access

For debugging and maintenance purposes you may want access the containers shell. You can access a running containers shell by starting bash using docker exec:

docker exec -it squid bash