Claranet PHP

Provides an opinionated, extensible PHP docker image build & run concept, which unifies common scenarios to build and run PHP applications / jobs in a container world. It ships with default configurations for nginx and php-fpm, supports the most important configurations to be set via environment variables and makes it easy to check external services (like a DBMS, cache, object-store) before proceeding with the container startup.

• Claranet PHP
  • TL;DR
  • Build & Run Concept
    • Main Sections
    • Subsections
    • Steps
    • Configure Sections
    • Docker Image Builds
  • Environment Variables
    • Docker Build Arguments
    • General
    • GCP
    • OS
    • Nginx
    • NodeJS
    • PHP
    • Mailing
  • Configuration
    • Nginx
    • PHP
      • Pre-compiled Modules
  • Cronjobs
  • Sending A Mail

TL;DR

• extends official docker php images
• provides generic build and life cycle infrastructure for containerized PHP applications (well prepared for kubernetes)
• shipped as PHP 7.1.x, 7.2.x and 7.3.x flavor
• there is a (build>base already run / build>base only prepared) flavor for each PHP version
• general run concept: docker run --rm -t claranet/php:1.1.58-php7.3.13 <main-section> [subsection] [subsection-args, ...]
• overview: docker run --rm -t claranet/php:1.1.58-php7.3.13 help
• supplied services
  • nginx
  • phpfpm
  • crond

Build image locally:

# generates local/claranet/php:1.1.58-php7.3.13
./bin/image.sh build

Build & Run Concept

System requirements: To be able to build this docker image, you need docker, gettext (envsubst) and the bash.

The concept is based on the good old .d directory concept from debian. There are 3 levels we need to discuss

1. main section
2. subsection
3. steps

A quick visual overview gives (see more details below)

Main Sections

A main section is collection of subsections which share an abstract topic. For example on default we provide the following main sections by default:

• build
• start
• stop
• test

Main sections are identified by looking for a .d directory within docker/. The entrypoint is designed to look up available main sections automatically. So you are able to introduce new main sections in your custom derivate of this image by adding an additional .d directory.

To execute all subsections of a main section, you need to call the main section from /entrypoint.sh. So running all build subsections is done by calling /entrypoint.sh build.

Note: not all main sections are able to run all subsections! (e.g. start). See configure sections for more details regarding this topic.

Subsections

Each main section must have at least one subsection. Subsections exist in order to organize related, self-contained steps (scripts). Subsections can be executed directly by specifying the subsection after the main section. So calling only the subsection base from the main section build, you need to execute /entrypoint.sh build base.

Subsections are directories within a main section - naming doesn't matter!

Calling a subsection results in a execution of all steps contained in the subsection. Steps are executed in alphanumeric order.

Note: you can describe subsections in the /entrypoint.sh help by configuring them

Steps

Context

A step lives inside a subsection, so the hierarchy looks like main section > subsection > step. A step is represented in form of a script. This script can be referenced by a symlink or live directly inside the subsection. Only bash scripts are currently supported. A step will be sourced by the caller, which makes all functions / vars from previous steps and docker/*.inc.sh files available to the script itself.

Each step current dir is set to $WORKDIR before executing the step.

Shared steps

Some steps are required in multiple subsections. To overcome the need of reimplementing / having duplicated steps steps can be references via symlinks. The Claranet PHP image already makes use of this and provides a directory called docker/shared_steps/. You can find scripts there, which will be referenced by multiple subsections.

If you need a step in multiple subsections, please make use of this mechanism!

Configure Sections

Main sections and subsections share the same way how they can be configured. A section may contain a file named META. If available, this file will be included by /entrypoint.sh help and in the run to iterate of all subsections (e.g. /entrypoint.sh build).

The help method uses the SECTION_DESCRIPTION to print more details about the available sections. In case of a main section it will be able to print a multi line string - standing by it's own. In case of a subsection the content should be kept short and one-line only - as it gets print after the subsection name.

META file schema:

# a one line description text which will be printed inside the help message
# Default: no description specified (see Configure Sections in documentation)
SECTION_DESCRIPTION="...your description..."

# AFFECT MAIN SECTIONS ONLY
# if false => requires the user to call a subsection directly
# and prohibits running all subsections by calling the main section only
# Default: true
CATCH_ALL_EXECUTION="<true|false>"

Docker Image Builds

The docker image build is, despite the recommendation, outsourced in multiple shell scripts, living within the section build. The build process is split in at least 2 subsections (parts): base and deps. The user is able and encouraged to add custom subsections and overwrite or enhance current subsections.

base:

The subsection base prepares the image OS by...

• configure APT sources
• install APT packages (listed in SYSTEM_PACKAGES env var)
• install / compile PHP modules
• install / configure PHP composer
• install nodejs and npm
• install git and configure it to use HTTPS instead of SSH for cloning
• install the newrelic daemon / php module if ENABLE_NEWRELIC is set to true

If you are lucky, you shouldn't be required to run this subsection in your customized image.

In order to speed up the build process for images based on this one, we already run the base subsection while building this image. If you need a lot of customization, you might need to run the base subsection by your own - this is why we also provide a -nobase flavoured image! The -nobase flavour comes with all the prepared scripts from build > base, but those script haven't been executed yet.

However, you should run the base subsection before running any other subsection!

deps:

Deps is a prepared-only subsection. It is meant to install application specific dependencies like npm or composer packages; apply code patches or do any other task to make the application code runnable.

This subsection should be called by the depending custom docker image!

Environment Variables

Checkout default values in the Dockerfile.

Docker Build Arguments

To easy docker builds, we provide a few handy options here

General

GCP

OS

Nginx

Nginx does not support environment variables by itself (except if you enable the lua script support...). So we are using envsubst before enabling configs from /etc/nginx/sites-available/*.conf.

NodeJS

PHP

We are exposing most of the important php.ini settings via environment variables and use the ini-env-var substitution feature from PHP for that.

PHP-FPM (Default Pool)

Mailing

Configuration

Nginx

• uses filesystem meta information cache
• configurable via DOCUMENT_ROOT, PHPFPM_HOST and PHPFPM_PORT environment variables

PHP

php-fpm

The php-fpm configuration is designed to match a generic pattern - optimized to leverage the usual load per container. Normally you shouldn't be required to change the fpm configuration at all - if your container needs to handle more requests, launch another one and balance the traffic.substitute

If you still need to extend the php-fpm config there are 2 options:

1. Adjust the environment variables for the default pool e.g. FPM_PM_MAX_CHILDREN.

2. The start > phpfpm subsection is prepared to launch different fpm pools. To launch e.g. a pool named wordpress, after you added the pools config to the container: /entrypoint.sh start phpfpm wordpress

It will start the default phpfpm pool if no other pool name is given.

NOTE: On default, OPCACHE is enabled and won't revalidate filesystem changes.

php.ini

In order to allow PHP config customization, this image uses the PHP ini parsers ability to substitute ENV vars for ini values. See available PHP env vars for more details.

Pre-compiled Modules

A list of module, coming with this docker image:

Cronjobs

To overcome the vixie-cron (debian default) environment variables issue (they are not propagated to launched cron-jobs), this image uses busybox' crond.

Cronjobs can be configured in the docker/etc/cron.d directory. You can put there a file per username (e.g. named root) with cronjob entries based on the normal cron config syntax and COPY those files via your Dockerfile to /etc/cron.d/ within the image.

# Cron config syntax
# m h   dom mon dow  command
  * *   *   *   *    mytask

Those files will be linked to /var/spool/cron/crontabs/ when start > crond gets executed.

Sending A Mail

Mailing via CLI is an easy topic with this image. Set ENABLE_SMTP to true and ssmtp will be pre-configured on the start subsections crond, pre-deployment and post-deployment. After that, you can use the ssmtp tool to send your mails synchronously.

For example:

ssmtp to@local <<EOF
To: to@local
From: from@local
Subject: [claranet] This is a nice mail

Helo,

from CLI

Regards,
Me - the CLI
EOF