Pluginhooks
Pluginhooks are a good way to jack into existing dokku infrastructure. You can use them to modify the output of various dokku commands or override internal configuration.
Pluginhooks are simply scripts that are executed by the system. You can use any language you want, so long as the script:
- Is executable
- Has the proper language requirements installed
For instance, if you wanted to write a pluginhook in PHP, you would need to have php
installed and available on the CLI prior to pluginhook invocation.
The following is an example for the nginx-hostname
pluginhook. It reverses the hostname that is provided to nginx during deploys. If you created an executable file named nginx-hostname
with the following code in your plugin, it would be invoked by dokku during the normal app deployment process:
#!/usr/bin/env bash
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
APP="$1"; SUBDOMAIN="$2"; VHOST="$3"
NEW_SUBDOMAIN=`echo $SUBDOMAIN | rev`
echo "$NEW_SUBDOMAIN.$VHOST"
Available Pluginhooks
There are a number of plugin-related pluginhooks. These can be optionally implemented by plugins and allow integration into the standard dokku plugin setup/backup/teardown process.
The following pluginhooks describe those available to a dokku installation. As well, there is an example for each pluginhook that you can use as templates for your own plugin development.
Info
The example pluginhook code is not guaranteed to be implemented as in within dokkku, and are merely simplified examples. Please look at the dokku source for larger, more in-depth examples.
install
- Description: Used to setup any files/configuration for a plugin.
- Invoked by:
dokku plugins-install
. - Arguments: None
- Example:
#!/usr/bin/env bash
# Sets the hostname of the dokku server
# based on the output of `hostname -f`
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
if [[ ! -f "$DOKKU_ROOT/HOSTNAME" ]]; then
hostname -f > $DOKKU_ROOT/HOSTNAME
fi
dependencies
- Description: Used to install system-level dependencies. Invoked by
plugins-install-dependencies
. - Invoked by:
dokku plugins-install-dependencies
- Arguments: None
- Example:
#!/usr/bin/env bash
# Installs nginx for the current plugin
# Supports both opensuse and ubuntu
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
case "$DOKKU_DISTRO" in
ubuntu)
export DEBIAN_FRONTEND=noninteractive
apt-get install --force-yes -qq -y nginx
;;
opensuse)
zypper -q in -y nginx
;;
esac
update
- Description: Can be used to run plugin updates on a regular interval. You can schedule the invoker in a cron-task to ensure your system gets regular updates.
- Invoked by:
dokku plugins-update
. - Arguments: None
- Example:
#!/usr/bin/env bash
# Update the herokuish image from git source
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
cd /root/dokku
sudo BUILD_STACK=true make install
commands help
- Description: Used to aggregate all plugin
help
output. Your plugin should implement ahelp
command in yourcommands
file to take advantage of this pluginhook. This must be implemented inside thecommands
pluginhook file. - Invoked by:
dokku help
- Arguments: None
- Example:
#!/usr/bin/env bash
# Outputs help for the derp plugin
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
case "$1" in
help | derp:help)
cat && cat<<EOF
derp:herp, Herps the derp
derp:serp [file], Shows the file's serp
EOF
;;
*)
exit $DOKKU_NOT_IMPLEMENTED_EXIT
;;
esac
backup-export
- Description: Used to backup files for a given plugin. If your plugin writes files to disk, this pluginhook should be used to echo out their full paths. Any files listed will be copied by the backup plugin to the backup tar.gz.
- Invoked by:
dokku backup:export
- Arguments:
$VERSION $DOKKU_ROOT
- Example:
#!/usr/bin/env bash
# Echos out the location of every `REDIRECT` file
# that are used by the apps
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
shopt -s nullglob
VERSION="$1"
DOKKU_ROOT="$2"
cat; for i in $DOKKU_ROOT/*/REDIRECT; do echo $i; done
backup-check
- Description: Checks that a backup being imported passes sanity checks.
- Invoked by:
dokku backup:import
- Arguments:
$VERSION $BACKUP_ROOT $DOKKU_ROOT $BACKUP_TMP_DIR/.dokku_backup_apps
- Example:
backup-import
- Description: Allows a plugin to import specific files from a
$BACKUP_ROOT
to theDOKKU_ROOT
directory. - Invoked by:
dokku backup:import
- Arguments:
$VERSION $BACKUP_ROOT $DOKKU_ROOT $BACKUP_TMP_DIR/.dokku_backup_apps
- Example:
#!/usr/bin/env bash
# Copies all redirect files from the backup
# into the correct app path.
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
shopt -s nullglob
VERSION="$1"
BACKUP_ROOT="$2"
DOKKU_ROOT="$3"
cd $BACKUP_ROOT
for file in */REDIRECT; do
cp $file "$DOKKU_ROOT/$file"
done
pre-build-buildpack
- Description: Allows you to run commands before the build image is created for a given app. For instance, this can be useful to add env vars to your container. Only applies to applications using buildpacks.
- Invoked by:
dokku build
- Arguments:
$APP
- Example:
post-build-buildpack
- Description: Allows you to run commands after the build image is create for a given app. Only applies to applications using buildpacks.
- Invoked by:
dokku build
- Arguments:
$APP
- Example:
pre-build-dockerfile
- Description: Allows you to run commands before the build image is created for a given app. For instance, this can be useful to add env vars to your container. Only applies to applications using a dockerfile.
- Invoked by:
dokku build
- Arguments:
$APP
- Example:
post-build-dockerfile
- Description: Allows you to run commands after the build image is create for a given app. Only applies to applications using a dockerfile.
- Invoked by:
dokku build
- Arguments:
$APP
- Example:
pre-release-buildpack
- Description: Allows you to run commands before environment variables are set for the release step of the deploy. Only applies to applications using buildpacks.
- Invoked by:
dokku release
- Arguments:
$APP
- Example:
#!/usr/bin/env bash
# Installs the graphicsmagick package into the container
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
source "$(dirname $0)/../common/functions"
dokku_log_info1" Installing GraphicsMagick..."
CMD="cat > gm && \
dpkg -s graphicsmagick > /dev/null 2>&1 || \
(apt-get update && apt-get install -y graphicsmagick && apt-get clean)"
ID=$(docker run -i -a stdin $IMAGE /bin/bash -c "$CMD")
test $(docker wait $ID) -eq 0
docker commit $ID $IMAGE > /dev/null
post-release-buildpack
- Description: Allows you to run commands after environment variables are set for the release step of the deploy. Only applies to applications using buildpacks.
- Invoked by:
dokku release
- Arguments:
$APP
- Example:
#!/usr/bin/env bash
# Installs a package specified by the `CONTAINER_PACKAGE` env var
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
source "$(dirname $0)/../common/functions"
dokku_log_info1" Installing $CONTAINER_PACKAGE..."
CMD="cat > gm && \
dpkg -s CONTAINER_PACKAGE > /dev/null 2>&1 || \
(apt-get update && apt-get install -y CONTAINER_PACKAGE && apt-get clean)"
ID=$(docker run -i -a stdin $IMAGE /bin/bash -c "$CMD")
test $(docker wait $ID) -eq 0
docker commit $ID $IMAGE > /dev/null
pre-release-dockerfile
- Description: Allows you to run commands before environment variables are set for the release step of the deploy. Only applies to applications using a dockerfile.
- Invoked by:
dokku release
- Arguments:
$APP
- Example:
post-release-dockerfile
- Description: Allows you to run commands after environment variables are set for the release step of the deploy. Only applies to applications using a dockerfile.
- Invoked by:
dokku release
- Arguments:
$APP
- Example:
check-deploy
- Description: Allows you to run checks on a deploy before dokku allows the container to handle requests.
- Invoked by:
dokku deploy
- Arguments:
$CONTAINER_ID $APP $INTERNAL_PORT $INTERNAL_IP_ADDRESS
- Example:
#!/usr/bin/env bash
# Disables deploys of containers based on whether the
# `DOKKU_DISABLE_DEPLOY` env var is set to `true` for an app
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
CONTAINERID="$1"; APP="$2"; PORT="$3" ; HOSTNAME="${4:-localhost}"
[[ -f "$DOKKU_ROOT/$APP/ENV" ]] && source $DOKKU_ROOT/$APP/ENV
DOKKU_DISABLE_DEPLOY="${DOKKU_DISABLE_DEPLOY:-false}"
if [[ "$DOKKU_DISABLE_DEPLOY" = "true" ]]; then
echo -e "\033[31m\033[1mDeploys disabled, sorry.\033[0m"
exit 1
fi
pre-deploy
- Description: Allows the running of code before the container's process is started.
- Invoked by:
dokku deploy
- Arguments:
$APP
- Example:
#!/usr/bin/env bash
# Runs gulp in our container
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
source "$(dirname $0)/../common/functions"
APP="$1"
IMAGE="dokku/$APP"
dokku_log_info1 "Running gulp"
id=$(docker run -d $IMAGE /bin/bash -c "cd /app && gulp default")
test $(docker wait $id) -eq 0
docker commit $id $IMAGE > /dev/null
dokku_log_info1 "Building UI Complete"
post-deploy
- Description: Allows running of commands after a deploy has completed. Dokku core currently uses this to switch traffic on nginx.
- Invoked by:
dokku deploy
- Arguments:
$APP $INTERNAL_PORT $INTERNAL_IP_ADDRESS
- Example:
#!/usr/bin/env bash
# Notify an external service that a successful deploy has occurred.
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
curl "http://httpstat.us/200"
pre-delete
- Description: Can be used to run commands before an app is deleted.
- Invoked by:
dokku apps:destroy
- Arguments:
$APP
- Example:
#!/usr/bin/env bash
# Clears out the gulp asset build cache for applications
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
APP="$1"; IMAGE="dokku/$APP"; GULP_CACHE_DIR="$DOKKU_ROOT/$APP/gulp"
if [[ -d $GULP_CACHE_DIR ]]; then
docker run --rm -v "$GULP_CACHE_DIR:/gulp" "$IMAGE" find /gulp -depth -mindepth 1 -maxdepth 1 -exec rm -Rf {} \; || true
fi
post-delete
- Description: Can be used to run commands after an application is deleted.
- Invoked by:
dokku apps:destroy
- Arguments:
$APP
- Example:
#!/usr/bin/env bash
# Runs a command to ensure that an app's
# postgres installation is removed
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
APP="$1";
dokku postgres:destroy $APP
docker-args-build
- Description:
- Invoked by:
dokku build
- Arguments:
$APP
- Example:
docker-args-deploy
- Description:
- Invoked by:
dokku deploy
- Arguments:
$APP
- Example:
docker-args-run
- Description:
- Invoked by:
dokku run
- Arguments:
$APP
- Example:
bind-external-ip
- Description: Allows you to disable binding to the external box ip
- Invoked by:
dokku deploy
- Arguments:
$APP
- Example:
#!/usr/bin/env bash
# Force always binding to the docker ip, no matter
# what the settings are for a given app.
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
echo false
post-domains-update
- Description: Allows you to run commands once the domain for an application has been updated.
- Invoked by:
dokku domains:add
,dokku domains:clear
,dokku domains:remove
- Arguments:
$APP
- Example:
#!/usr/bin/env bash
# Reloads haproxy for our imaginary haproxy plugin
# that replaces the nginx-vhosts plugin
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
sudo service haproxy reload
git-pre-pull
- Description:
- Invoked by:
dokku git-upload-pack
- Arguments:
$APP
- Example:
git-post-pull
- Description:
- Invoked by:
dokku git-upload-pack
- Arguments:
$APP
- Example:
nginx-hostname
- Description: Allows you to customize the hostname for a given application.
- Invoked by:
dokku domains:setup
- Arguments:
$APP $SUBDOMAIN $VHOST
- Example:
#!/usr/bin/env bash
# Reverses the hostname for the application
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
APP="$1"; SUBDOMAIN="$2"; VHOST="$3"
NEW_SUBDOMAIN=`echo $SUBDOMAIN | rev`
echo "$NEW_SUBDOMAIN.$VHOST"
nginx-pre-reload
- Description: Run before nginx reloads hosts
- Invoked by:
dokku nginx:build-config
- Arguments:
$APP $INTERNAL_PORT $INTERNAL_IP_ADDRESS
- Example:
#!/usr/bin/env bash
# Runs a check against all nginx conf files
# to ensure they are valid
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
nginx -t
receive-app
- Description: Allows you to customize what occurs when an app is received. Normally just triggers an application build.
- Invoked by:
dokku git-hook
,dokku ps:rebuild
- Arguments:
$APP $REV
- Example:
#!/usr/bin/env bash
# For our imaginary mercurial plugin, triggers a rebuild
set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
APP="$1"; REV="$2"
dokku hg-build $APP $REV
receive-branch
- Description: Allows you to customize what occurs when a specific branch is received. Can be used to add support for specific branch names
- Invoked by:
dokku git-hook
,dokku ps:rebuild
- Arguments:
$APP $REV $REFNAME
- Example:
#!/bin/bash
# Gives dokku the ability to support multiple branches for a given service
# Allowing you to have multiple staging environments on a per-branch basis
reference_app=$1
refname=$3
newrev=$2
APP=${refname/*\//}.$reference_app
if [[ ! -d "$DOKKU_ROOT/$APP" ]]; then
REFERENCE_REPO="$DOKKU_ROOT/$reference_app
git clone --bare --shared --reference "$REFERENCE_REPO" "$REFERENCE_REPO" "$DOKKU_ROOT/$APP" > /dev/null
fi
pluginhook receive-app $APP $newrev