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Base Images

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ClamAV

ClamAV set up to run in daemon mode over the default port (3310).

FTPS

Very Secure FTP (vsftpd) supporting TLS file transfer.

MariaDB

Latest stable releases of MariaDB with automated backups.

MariaDB: Executables

Nginx

Super lightweight Nginx image with various helper configuration files.

Nginx: Helpers

Nginx: Executables

Nginx PHP

Nginx base image with PHP (7.3, 7.4, and 8.0).

Nginx PHP: Executables

Nginx Proxy

Automated proxy server using Nginx base image and the getssl script.

Nginx Proxy: Executables

Nginx WebDAV

Nginx base image with WebDAV extensions.

PHP

PHP installed by itself to be used in CLI mode.

PostgreSQL

Latest stable releases of PostgreSQL with automated backups.

PostgreSQL: Executables

Redis

Latest redis cache server running in daemon mode over the default port (6379).

Applications

FreeScout

Ready-to-go FreeScout helpdesk with all PHP dependencies.

FreshRSS

Ready-to-go FreshRSS news reader with all PHP dependencies.

WordPress

Ready-to-go WordPress helpdesk with all PHP dependencies.

Home

Welcome to the bfren Docker ecosystem

This started out as a project to learn Docker and have control over the versions of the various pieces of FOSS I use. But I hope you find the ecosystem as useful as I do!

The instructions assume a working knowledge of shell programming, Docker, and Docker Compose. Like most documentation they are also a work in progress...

Licence

(unless otherwise stated). Copyright (c) 2020-2022 bfren (unless otherwise stated).

MIT

Alpine S6: Executables

Various helper executables for interacting with S6 and the container environment.

Output

bf-svc-finish

Outputs service closing down debug message and optionally terminates all running services. Usually used in /etc/services.d/xxx/finish file to show

Arguments

  • -s X outputs a message that service "X" is shutting down

  • -t terminates all other services as well

Usage

$ bf-svc-finish -s cron
[bf] 2021-09-23 10:21:52 | cron/finish: Service closing down.

$ bf-svc-finish -s cron -t
[bf] 2021-09-19 18:00:00 | cron/finish: Service closing down.
[bf] 2021-09-19 18:00:00 | bf-env: BF_TERMINATING=1.
[bf] 2021-09-19 18:00:00 | bf-svc-terminate: Terminating all services.
[bf] 2021-09-19 18:00:00 | cron-log/finish: Service closing down.
[cont-finish.d] executing container finish scripts...
[cont-finish.d] 00-clear: executing...
[bf] 2021-09-19 18:00:00 | 00-clear: Clearing /tmp... (bf-clear)
[bf] 2021-09-19 18:00:00 | 00-clear: done. (bf-clear)
[bf] 2021-09-19 18:00:00 | 00-clear: Clearing caches... (bf-clear)
[bf] 2021-09-19 18:00:00 | 00-clear: done. (bf-clear)
[cont-finish.d] 00-clear: exited 0.
[cont-finish.d] done.
[s6-finish] waiting for services.
[s6-finish] sending all processes the TERM signal.
[s6-finish] sending all processes the KILL signal and exiting.

Helpers

bf-clear-src

Clears contents of /etc/bf/src.

Usage

$ bf-clear-src
[bf] 2021-09-19 18:00:00 | bf-clear-src: Clearing /etc/bf/src...
[bf] 2021-09-19 18:00:00 | bf-clear-src: done.

bf-cron

Run all scripts within a cron directory.

Arguments

  • -h Show usage

  • -q Run quietly (otherwise it will output that the cron is being run to the logs - individual scripts may still send output)

  • DIRECTORY - the directory within /etc/periodic to run

Usage

$ bf-cron 1min
[bf] 2021-09-19 18:00:00 | bf-cron: /etc/periodic/1min.

$ bf-cron -q 1min
// scripts are run with no output

bf-env

Adds a container environment variable called $1 with value $2.

Arguments

  1. Variable name

  2. Variable value

Usage

$ bf-env "DOCS" "Docker Docs"
[bf] 2021-09-19 18:00:00 | bf-env: DOCS=Docker Docs.

bf-fix-attrs

Usage

$ bf-fix-attrs
[bf] 2021-09-19 18:00:00 | bf-fixattrs: Applying ownership & permissions fixes...
[bf] 2021-09-19 18:00:00 | bf-fixattrs: 00-alpine-s6: applying...
[bf] 2021-09-19 18:00:00 | bf-fixattrs: 00-alpine-s6: exited 0.
[bf] 2021-09-19 18:00:00 | bf-fixattrs: done.

bf-forward

Forwards errors logged in $2 to Docker logs; if $2 is not set, disables service $1.

Arguments

  1. Service name.

  2. Absolute path to log file.

Usage

$ bf-forward cron-log /var/log/cron.log
[bf] 2021-09-19 18:00:00 | [bf] 2021-09-23 09:57:59 | cron-log/run: Forwarding cron-log - /var/log/cron.log. (bf-forward)

bf-svc

Uses S6 to control the service named $2.

Arguments

  1. Control action: 'disable', 'restart', 'start', 'stop'

  2. Service name

Usage

$ bf-svc restart cron
[bf] 2021-09-19 18:00:00 | bf-svc: Restarting service 'cron'.
[bf] 2021-09-19 18:00:00 | cron/finish: Service closing down.
[bf] 2021-09-19 18:00:00 | cron/run: Starting cron.
crond: crond (busybox 1.33.1) started, log level 8

bf-svc-terminate

Terminates all running services - usually used in /etc/services.d/xxx/finish file - which also closes down (and potentially restarts) the whole container.

Usage

$ bf-svc-terminate
[bf] 2021-09-19 18:00:00 | bf-env: BF_TERMINATING=1.
[bf] 2021-09-19 18:00:00 | bf-svc-terminate: Terminating all services.
[bf] 2021-09-19 18:00:00 | cron/finish: Service closing down.
[bf] 2021-09-19 18:00:00 | cron-log/finish: Service closing down.
[cont-finish.d] executing container finish scripts...
[cont-finish.d] 00-clear: executing...
[bf] 2021-09-19 18:00:00 | 00-clear: Clearing /tmp... (bf-clear)
[bf] 2021-09-19 18:00:00 | 00-clear: done. (bf-clear)
[bf] 2021-09-19 18:00:00 | 00-clear: Clearing caches... (bf-clear)
[bf] 2021-09-19 18:00:00 | 00-clear: done. (bf-clear)
[cont-finish.d] 00-clear: exited 0.
[cont-finish.d] done.
[s6-finish] waiting for services.
[s6-finish] sending all processes the TERM signal.
[s6-finish] sending all processes the KILL signal and exiting.

Alpine: Executables

Various helper executables for providing standard output and simplifying common tasks.

Output

bf-debug

Arguments

  1. Text to output

  2. [Optional] Script / executable name

Usage

bf-done

Arguments

  1. [Optional] Script / executable name

Usage

bf-e

Echoes $3 to stdout in colour $2 with prefix: "[$1] %Y-%m-%d %H:%M:%S".

Arguments

  1. Namespace (default value for other output helper executables is 'bf')

  2. Text to output

  3. [Optional] Script / executable name

Usage

bf-echo

Arguments

  1. Text to output

  2. [Optional] Script / executable name

Usage

bf-error

Arguments

  1. Text to output

  2. [Optional] Script / executable name

Usage

bf-notok

Arguments

  1. Text to output

  2. [Optional] Script / executable name

Usage

bf-ok

Echoes "$1: $2" to stdout in green with prefix.

Arguments

  1. Text to output

  2. [Optional] Script / executable name

Usage

Helpers

bf-adduser

Create user with id $2, group with id $3, both with name $1, and no password.

Arguments

  1. User and group name

  2. [Optional] User ID (default: 1000)

  3. [Optional] Group ID (default: UID)

Usage

bf-ch

Changes ownership and/or permissions of file / directory glob.

Arguments

Required (one or both):

  • -o X use chown to set ownership to "X"

  • -m Y use chmod to set permissions to "Y"

Optional:

  • -t f|d apply only to files ("f") or directories ("d")

  • -rif -t is not specified, applies action recursively to all files and directories

Usage

bf-clear

Clears contents of /tmp and apk cache.

Usage

bf-esh

Calls esh in a consistent manner.

Arguments

  1. Path to input (template) file

  2. Path to output (generated) file

Usage

bf-image

Display name and version of the current image, and a link to the GitHub repository.

Usage

bf-install

Usage

This is the basic structure of Dockerfiles based on the Alpine S6 image, copying overlay and then running the standard installation.

bf-rmrf

Runs rm -rf $1 safely: doing nothing if $1 is empty. This is handy if the path you are deleting is contained in a variable (it effectively stops rm -rf /!).

Arguments

  1. Folder path / file glob to delete.

Usage

bf-rnd

Generates a string of random letters and numbers of length $1.

Arguments

  1. [Optional] Number of characters to return

Usage

bf-test-url

Uses wget to test URL $1.

Arguments

  1. URL to test

Usage

bf-tz

Sets the container's timezone to $1. (Installs tzdata package, changes timezone and then removes tzdata).

Arguments

  1. Valid timezone (e.g. Europe/London)

Usage

Note the change in time on line 12.

Re-applies attributes and permissions defined in /etc/fix-attrs.d. Based on code from .

Echoes "$1: $2" to stdout in grey with prefix (see ) - but only if BF_DEBUG is set to "1".

Echoes 'done.' to stdout in green with prefix (see ).

ANSI colour code (see e.g. )

Echoes "$1: $2" to stdout in default colour with prefix (see ).

Echoes "$1: $2" to stdout in red with prefix (see ), and returns 1. This will end execution of the calling script if you use, e.g. set -euo pipefail at the top of your scripts (recommended).

Like echoes "$1: $2" to stdout in red with prefix, but doesn't end execution of calling script.

Run install /tmp/install and then perform cleanup (see ). Within the ecosystem this would normally be used in a Dockerfile

S6 Overlay
$ bf-debug "Hi"
[bf] 2021-09-19 18:00:00 | Hi # (in grey)

$ bf-debug "Hi" "alpine-s6/docs"
[bf] 2021-09-19 18:00:00 | alpine-s6/docs: Hi # (in grey)
$ bf-done
[bf] 2021-09-19 18:00:00 | done. # (in green)

$ bf-done "alpine-s6/docs"
[bf] 2021-09-19 18:00:00 | alpine-s6/docs: done. # (in green)
$ bf-e "docs" "\e[91m" "Hi"
[docs] 2021-09-19 18:00:00 | Hi # (in red)

$ bf-e "docs" "\e[92m" "Hi" "alpine-s6"
[docs] 2021-09-19 18:00:00 | alpine-s6: Hi # (in green)
$ bf-echo "Hi"
[bf] 2021-09-19 18:00:00 | Hi # (in black / white)

$ bf-echo "Hi" "docs"
[bf] 2021-09-19 18:00:00 | docs: Hi # (in black / white)
$ bf-error "Die"
[bf] 2021-09-19 18:00:00 | Die # (in red)

$ bf-error "Die" "docs"
[bf] 2021-09-19 18:00:00 | docs: Die # (in red)
$ bf-notok "Error"
[bf] 2021-09-19 18:00:00 | Error # (in red)

$ bf-notok  "Error" "docs"
[bf] 2021-09-19 18:00:00 | docs: Error # (in red)
$ bf-ok "Hi"
[bf] 2021-09-19 18:00:00 | Hi # (in green)

$ bf-ok  "Hi" "docs"
[bf] 2021-09-19 18:00:00 | docs: Hi # (in green)
$ bf-adduser "fred"
[bf] 2021-09-19 18:00:00 | bf-adduser: Adding user and group 'fred'...
[bf] 2021-09-19 18:00:00 | bf-adduser: done. 'fred'... # (in green)
$ cat /etc/passwd
...
fred:x:1000:1000:Linux User,,,:/home/fred:/bin/ash

$ bf-adduser "fred" 1001
[bf] 2021-09-19 18:00:00 | bf-adduser: Adding user and group 'fred'...
[bf] 2021-09-19 18:00:00 | bf-adduser: done. 'fred'... # (in green)
$ cat /etc/passwd
...
fred:x:1001:1001:Linux User,,,:/home/fred:/bin/ash

$ bf-adduser "fred" 1002 1003
[bf] 2021-09-19 18:00:00 | bf-adduser: Adding user and group 'fred'...
[bf] 2021-09-19 18:00:00 | bf-adduser: done. 'fred'... # (in green)
$ cat /etc/passwd
...
fred:x:1002:1003:Linux User,,,:/home/fred:/bin/ash
$ bf-ch -o "fred" -m 777 -t f /tmp
[bf] 2021-09-19 18:00:00 | bf-ch: Applying chown fred to /tmp.
[bf] 2021-09-19 18:00:00 | bf-ch:  .. type f.
[bf] 2021-09-19 18:00:00 | bf-ch: Applying chmod 777 to /tmp.
[bf] 2021-09-19 18:00:00 | bf-ch:  .. type f.

$ bf-ch -o "fred" -m 777 -r /tmp
[bf] 2021-09-19 18:00:00 | bf-ch: Applying chown fred to /tmp.
[bf] 2021-09-19 18:00:00 | bf-ch:  .. recursively.
[bf] 2021-09-19 18:00:00 | bf-ch: Applying chmod 777 to /tmp.
[bf] 2021-09-19 18:00:00 | bf-ch:  .. recursively.
$ bf-clear
[bf] 2021-09-19 18:00:00 | bf-clear: Clearing /tmp...
[bf] 2021-09-19 18:00:00 | bf-clear: done.
[bf] 2021-09-19 18:00:00 | bf-clear: Clearing caches...
[bf] 2021-09-19 18:00:00 | bf-clear: done.
$ bf-esh /path/to/template /path/to/output
[bf] 2021-09-19 18:00:00 | bf-esh: /path/to/output created.
$ bf-image
[bf] 2021-09-19 18:00:00 | bf-image: bfren alpine 1.2.0.
[bf] 2021-09-19 18:00:00 | bf-image: https://github.com/bfren/docker-alpine.
FROM bfren/alpine-s6:alpine3.14

COPY ./overlay /

RUN bf-install
$ bf-rmrf ""
[bf] 2021-09-19 18:00:00 | bf-rmrf: Cannot remove ''.

bf-rmrf /tmp/*
[bf] 2021-09-19 18:00:00 | bf-rmrf: Removing /tmp/*.
$ bf-rnd
7ceeezFaFzbuaHujA2ST2s3ACPAnAEoUqqVXBcdk

$ bf-rnd 10
D8ORzTX56m

$ RND=$(bf-rnd)
$ echo ${RND}
cm1HuNlkQwbqd5TeApoHsxfYE6X1MWxKnuiBbjFr
$ bf-test-url https://fake.url
[bf] 2021-09-19 18:00:00 | bf-test-url: Loading https://fake.url.
wget: bad address 'fake.url'

$ bf-test-url https://bbc.co.uk
[bf] 2021-09-19 18:00:00 | bf-test-url: Loading https://bbc.co.uk.
Connecting to bbc.co.uk (151.101.0.81:443)
Connecting to www.bbc.co.uk (212.58.237.254:443)
remote file exists
$ bf-tz UTC
[bf] 2021-09-19 18:00:00 | bf-tz: Installing tzdata packages.
fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/main/x86_64/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/community/x86_64/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/edge/main/x86_64/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/edge/community/x86_64/APKINDEX.tar.gz
(1/2) Installing tzdata (2021a-r0)
(2/2) Installing .tz (20210923.092854)
Executing busybox-1.33.1-r3.trigger
OK: 9 MiB in 17 packages
[bf] 2021-09-19 18:00:00 | bf-tz: Setting timezone to UTC...
[bf] 2021-09-19 17:00:00 | bf-tz: Removing tzdata packages.
(1/2) Purging .tz (20210923.092854)
(2/2) Purging tzdata (2021a-r0)
Executing busybox-1.33.1-r3.trigger
OK: 6 MiB in 15 packages
[bf] 2021-09-19 17:00:00 | bf-tz: done.

$ cat /etc/localtime
TZif2UTCTZif2UTC
UTC0
here
bf-ok
bf-e
bf-e
bf-error
bf-clear

Debian S6

Another base image for the bfren ecosystem, containing Debian installed with the S6 Overlay.

Acknowledgements

Environment Variables, Packages, Layout

Apache PHP

Base Apache + PHP image with MySQL enabled.

Acknowledgements

Ports

Port
Description

80

Serves HTTP content (Apache requires permissions for user 1000, e.g. www-data).

Volumes

Volume
Purpose

/var/www/html/

From base image: files are served from this directory.

Debian

The base image for the bfren ecosystem, containing Alpine Linux and various helper executables.

Acknowledgements

Tags

x.x and x.x.x refer to the bfren image versions.

In addition, you can add -dev and -beta suffixes to access development / test builds (see Docker Hub for further details).

Environment Variables, Packages, Cron & Templating

bf-e

(GitHub) (Docker Hub)

The is a version of the S6 supervisor which has various useful features for containers and managing services.

See .

(GitHub) (Docker Hub)

Based on the for PHP 5.6.40 with Apache and mysql extension installed.

(GitHub) (Docker Hub)

is a cut-down distribution of designed specifically for use in containers.

is a lightweight templating engine using POSIX-compatible syntax.

Debian Version
Tags

See .

Source files
Container images
S6 Overlay
Alpine S6
Source files
Container images
official PHP image

10 (buster)

debian10, debian10-x, debian10-x.x, debian10-x.x.x

11 (bullseye)

debian11, debian11-x, debian11-x.x, debian11-x.x.x

12 (bookworm)

debian12, debian12-x, debian12-x.x, debian12-x.x.x

sid

debiansid, debiansid-x, debiansid-x.x, debiansid-x.x.x

Source files
Container images
Debian Slim
Debian
esh
Alpine

ASP.NET

.NET and ASP.NET runtimes pre-installed (versions 3.1, 5.0, and 6.0).

Acknowledgements

Tags

.NET Version
Tags

3.1

net3, net3.1, net3.1.21

5.0

net5, net5.0, net5.0.12

6.0

latest, net6, net6.0, net6.0.0

In addition, you can add -dev and -beta suffixes to access development / test builds (see Docker Hub for further details).

Ports

Port
Description

5000

Serves HTTP content from your application.

Volumes

Volume
Purpose

/app/live

Contains live application files.

/app/publish

Environment Variables

Name
Values
Description
Default

ASPNET_ASSEMBLY

string

The filename of the assembly to execute.

None - required

ASPNETCORE_URLS

string

Default value binds web server to port 5000 - should not normally need to be changed.

DOTNET_RUNNING_IN_CONTAINER

'true' or 'false'

This should always be set to true - it tells dotnet that it is running in a container environment.

'true'

DOTNET_SYSTEM_GLOBALIZATION_INVARIANT

'true' or 'false'

'true'

Alpine

The base image for the bfren ecosystem, containing Alpine Linux and various helper executables.

Acknowledgements

Tags

x.x and x.x.x refer to the bfren image versions.

Alpine Version
Tags

3.12

alpine3.12, alpine3.12.9, alpine3.12-x.x, alpine3.12-x.x.x

3.13

alpine3.13, alpine3.13.7, alpine 3.13-x.x, alpine3.13-x.x.x

3.14

alpine3.14, alpine3.14.3, alpine3.14-x.x, alpine3.14-x.x.x

3.15

latest, alpine3, alpine3.15, alpine3.15.0, alpine3.15-x.x, alpine3.15-x.x.x

edge

alpineedge, alpineedge-x.x, alpineedge-x.x.x

In addition, you can add -dev and -beta suffixes to access development / test builds (see Docker Hub for further details).

Environment Variables

Name
Values
Description
Default

BF_DEBUG

0 or 1

Set to 0 to disable debug log output messages.

1

Packages

As well as the standard repositories, the edge repos are tagged with @edgemain and @edgecomm. This means you can, for example, do apk add curl@edgemain or apk add php8@edgecomm to add the edge versions of packages.

Cron

This image contains only one service: cron, which is enabled by default. If you want to add scripts or executables to the cron you have two options.

Option 1: /etc/periodic/

The simplest way to add tasks to the cron in Alpine Linux is to place an executable file in one of the directories under /etc/periodic/ (remember to set the executable attribute in /etc/fix-attrs.d/):

$ ls /etc/periodic/
1min    15min    daily    hourly    monthly    weekly

Option 2: /etc/crontabs/root

If you want more control over your cron tasks you can create a normal crontab file:

$ head -n 1 /etc/crontabs/root
0 */8 * * * db-backup > /dev/null 2>&1

Templating with esh

All dynamic configuration files in the bfren ecosystem are built using esh, and the default location for those templates is /etc/bf/templates.

Debian: Executables

Various helper executables for providing standard output and simplifying common tasks.

Debian S6: Executables

Various helper executables for interacting with S6 and the container environment.

ASP.NET: Executables

Various helper executables for interacting with your .NET application.

Helpers

aspnet-restart

Restarts ASP.NET application.

Usage

aspnet-start

Starts ASP.NET application.

If you try to start an application that is already running you will get an error as it won't be able to bind to port 5000. You should never need to use this executable as it is called when the container starts.

Usage

aspnet-switch-terminate

Stops ASP.NET application, switches live and published code, and terminates the container (you will need to have the restart policy set to 'always').

Usage

healthcheck

Usage

Alpine S6

The base image for much of the bfren ecosystem, containing Alpine Linux installed with the S6 Overlay.

Acknowledgements

Environment Variables

Packages

The image comes with the S6 Overlay and all its dependencies.

Layout

The most important concept in these images is the /overlay/ directory, which is copied from the source over the top of the image. You can use whatever structure you like within that.

So, for example, the edge repositories are added via the /overlay/etc/apk/repositories file, which is copied over the top of the base image filesystem by the Dockerfile command COPY ./overlay /.

You can add any files you want to the image this way.

S6 Startup

Every time the container starts, the S6 Overlay runs the same series of scripts. These allow you to ensure that there is a consistent environment for your service.

The sequence is as follows (all should be contained within the /overlay/ directory):

  1. /etc/fix-attrs.d/ - set required permissions

  2. /etc/cont-init.d/ - run initialisation scripts

  3. /etc/services.d/ - register the services you want to be supervised

My rule of thumb is that the first image uses 0-based files. Then the next uses 1-based files, then 2-based, etc. As S6 loads these files alphabetically, this practice ensures base permissions and configuration is always done first.

Permissions

For me, permissions are one the most powerful and most frustrating features of Linux. These are set by adding files to /overlay/etc/fix-attrs.d/. Good practice is to prefix these files with a number so you have control over the order in which they are loaded. For example:

  • First we have the absolute path to the file or directory to set permissions for

  • Next we have true or false whether or not to recurse (obviously meaningless for a file)

  • Then we have the owner of the file or directory

Initialisation

After the permissions are set, the scripts in /etc/cont-init.d/ are run. Here you might want to run installation routines, create configuration files, etc.

Notice that in this example the files begin 10- and 11- as mentioned earlier.

(It does mean there can't be more than ten initialisation scripts per image, but frankly if there are more we need to ask the question, is the image trying to do too much? A key principle of Docker is that an image should do one thing.)

Services

All the services you want to be managed by S6 go in /etc/services.d/. The name of the next directory will be the name of the service, e.g. cron. Within that the minimum you need is a file named run, which contains the script necessary to start your service.

Here is the run file from the cron service of this image:

As you can see, it doesn't have to be complex! The trick with this particular example is the -f flag which tells the cron daemon to run in the foreground. If it ran in the background, S6 wouldn't be able to supervise it. This is something to watch out for when creating your own services.

You can have as many services as you want - however the main point of Docker is to separate services into their own 'contained' environments. Therefore I try to keep the discipline of one 'main' service, and only adding 'supporting' services beyond that.

Note that service directories are not given a number prefix - they will run in any order. S6 does have ways of making a service wait for another service to start, but it's complex and very fiddly. Plus, if something needs to happen before your service starts, it should probably go in /etc/cont-init.d/ instead.

In your main service directory, I suggest also including a finish file:

This is also from the cron service of this image, but you'll see it in the main service directory of all the bfren images. What this does is tell S6 to close down all the services gracefully when this one quits, and then stop the container. You don't have to do this, but it's good practice to ensure a safe closedown of your container services when one of them crashes.

It means you may want to set restart to unless-stopped instead of always, or you could end up with a never-ending loop of a container starting, crashing, restarting, crashing, etc.

Container Environment

One of the most useful tricks when using S6 is to make use of the following directive to import all environment variables into the current script:

You do not get Docker's environment variables in scripts by default however, so you need to use the S6 helper function with-contenv (with container environment). Then you can access all the environment variables you want.

Have fun!

And that's it! There is a lot more to it if you want to get complicated - I suggest you read the S6 documentation if you want to go deeper..

(GitHub) (Docker Hub)

Comes pre-installed with the and all required dependencies.

Publish updated files to this directory and use to make it go live.

See and .

(GitHub) (Docker Hub)

is a tiny distribution of Linux designed specifically for use in containers.

is a lightweight templating engine using POSIX-compatible syntax.

If you need to build the image with a different timezone to the default ("Europe/London"), you can do so by setting the TZ ARG, or by installing the tzdata package. (Please note this is only possible if you are building the image yourself - otherwise you will need to use .)

It's pretty obvious how frequently they run! An example of this method can be found in the image.

However, if you do this, remember you will be overriding the default file when your /overlay/ is copied over the image files, so you need to include the if you don't want to break the cron further down the line.

The image comes pre-installed with , a simple shell-based templating engine. It is extremely lightweight, and very easy to use.

See .

See .

Uses to request the URL set by ASPNETCORE_URLS and exits with code 0 if response is HTTP 200 OK.

(GitHub) (Docker Hub)

The is a version of the S6 supervisor which has various useful features for containers and managing services.

Name
Values
Description
Default

The S6 Overlay does more before and after all this - additional information can be found in . These three folders are where you will most often hook into the container processes.

Finally we have the permissions, first fmode (file permissions) and then dmode (directory permissions). I find the extremely useful for generating these.

You can have as many of these as you wish, and you can reapply them at any point by using .

For example, in the image the following two scripts run in this stage:/etc/cont-init.d/10-initial # downloads the latest virus definitions

So, for example, in the image, the main service is nginx itself, but there are also two services to manage logging.

This is an example from the image (in fact it is the contents of the 11-updater file we looked at earlier). One of that image's environment variables is FRESHCLAM_PER_DAY which allows you to define how many times a day you want freshclam to run.

Source files
Container images
ASP.NET runtime
Source files
Container images
Docker Alpine
esh
Nginx PHP
default directives
esh
bf-tz
$ aspnet-restart
[bf] 2021-09-19 18:00:00 | restart: Restarting application.
[bf] 2021-09-19 18:00:00 | bf-svc: Restarting service 'aspnet'.
$ aspnet-start
[bf] 2021-09-19 18:00:00 | start: Starting ASP.NET application.
[bf] 2021-09-19 18:00:00 | start:  .. /app/live/ASPNET_ASSEMBLY.
$ aspnet-switch-terminate
[bf] 2021-09-19 18:00:00 | bf-svc: Disabling service 'aspnet'.
[bf] 2021-09-19 18:00:00 | switch: Switching code...
[bf] 2021-09-19 18:00:00 | switch:  .. moving live files to src.OCPFfa
[bf] 2021-09-19 18:00:00 | switch:  .. moving published files to /app/live
[bf] 2021-09-19 18:00:00 | switch:  .. moving live files to /app/publish
[bf] 2021-09-19 18:00:00 | switch: done.
[bf] 2021-09-19 18:00:00 | bf-env: BF_TERMINATING=1.
[bf] 2021-09-19 18:00:00 | bf-svc-terminate: Terminating all services.
$ healthcheck
[bf] 2021-09-19 18:00:00 | healthcheck: Loading http://localhost:5000. (bf-test-url)
Connecting to localhost:5000 (127.0.0.1:5000)
remote file exists

BF_CRON_LOG_LEVEL

0-8

Cron log level (0 is most verbose).

8

# fix-attrs.d/00-bin
/usr/local/bin/healthcheck false root:root 0500 0500

# fix-attrs.d/01-user
/etc/user true www:www 0644 0755
/etc/cont-inid.d/11-updater # registers the freshclam update daemon
#!/bin/sh
/usr/sbin/crond -f
#!/bin/sh
s6-svscanctl -t /var/run/s6/services
#!/usr/bin/with-contenv sh
freshclam -d -c ${FRESHCLAM_PER_DAY}
environment variable
http://+:5000
here
here
Alpine: Executables
Alpine S6: Executables
Source files
Container images
S6 Overlay
their documentation
chmod calculator
ClamAV
Nginx
ClamAV
aspnet-switch-terminate
bf-test-url
bf-fix-attrs