#!/bin/sh
#
# The docker HA resource agent creates and launches a docker container
# based off a supplied docker image. Containers managed by this agent
# are both created and removed upon the agent's start and stop actions.
#
# Copyright (c) 2014 David Vossel <davidvossel@gmail.com>
#                    All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
# Further, this software is distributed without any warranty that it is
# free of the rightful claim of any third person regarding infringement
# or the like.  Any license provided herein, whether implied or
# otherwise, applies only to this software file.  Patent licenses, if
# any, provided herein do not apply to combinations of this program with
# other software, or any other product whatsoever.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
#

#######################################################################
# Initialization:

: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs

# Parameter defaults

OCF_RESKEY_reuse_default="0"

: ${OCF_RESKEY_reuse=${OCF_RESKEY_reuse_default}}

#######################################################################

meta_data()
{
	cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="docker" version="1.0">
<version>1.0</version>

<longdesc lang="en">
The docker HA resource agent creates and launches a docker container
based off a supplied docker image. Containers managed by this agent
are both created and removed upon the agent's start and stop actions.
</longdesc>
<shortdesc lang="en">Docker container resource agent.</shortdesc>

<parameters>
<parameter name="image" required="1" unique="0">
<longdesc lang="en">
The docker image to base this container off of.
</longdesc>
<shortdesc lang="en">docker image</shortdesc>
<content type="string"/>
</parameter>

<parameter name="name" required="0" unique="0">
<longdesc lang="en">
The name to give the created container. By default this will
be that resource's instance name.
</longdesc>
<shortdesc lang="en">docker container name</shortdesc>
<content type="string"/>
</parameter>

<parameter name="allow_pull" unique="0">
<longdesc lang="en">
Allow the image to be pulled from the configured docker registry when
the image does not exist locally. NOTE, this can drastically increase
the time required to start the container if the image repository is
pulled over the network.
</longdesc>
<shortdesc lang="en">Allow pulling non-local images</shortdesc>
<content type="boolean"/>
</parameter>

<parameter name="run_opts" required="0" unique="0">
<longdesc lang="en">
Add options to be appended to the 'docker run' command which is used
when creating the container during the start action. This option allows
users to do things such as setting a custom entry point and injecting
environment variables into the newly created container. Note the '-d'
option is supplied regardless of this value to force containers to run
in the background.

NOTE: Do not explicitly specify the --name argument in the run_opts. This
agent will set --name using either the resource's instance or the name
provided in the 'name' argument of this agent.

</longdesc>
<shortdesc lang="en">run options</shortdesc>
<content type="string"/>
</parameter>

<parameter name="run_cmd" required="0" unique="0">
<longdesc lang="en">
Specify a command to launch within the container once
it has initialized.
</longdesc>
<shortdesc lang="en">run command</shortdesc>
<content type="string"/>
</parameter>

<parameter name="mount_points" required="0" unique="0">
<longdesc lang="en">
A comma separated list of directories that the container is expecting to use.
The agent will ensure they exist by running 'mkdir -p' 
</longdesc>
<shortdesc lang="en">Required mount points</shortdesc>
<content type="string"/>
</parameter>

<parameter name="monitor_cmd" required="0" unique="0">
<longdesc lang="en">
Specify the full path of a command to launch within the container to check
the health of the container. This command must return 0 to indicate that
the container is healthy. A non-zero return code will indicate that the
container has failed and should be recovered.

If 'docker exec' is supported, it is used to execute the command. If not,
nsenter is used.

Note: Using this method for monitoring processes inside a container
is not recommended, as containerd tries to track processes running
inside the container and does not deal well with many short-lived
processes being spawned. Ensure that your container monitors its
own processes and terminates on fatal error rather than invoking
a command from the outside.
</longdesc>
<shortdesc lang="en">monitor command</shortdesc>
<content type="string"/>
</parameter>

<parameter name="force_kill" required="0" unique="0">
<longdesc lang="en">
Kill a container immediately rather than waiting for it to gracefully
shutdown
</longdesc>
<shortdesc lang="en">force kill</shortdesc>
<content type="boolean"/>
</parameter>

<parameter name="reuse" required="0" unique="0">
<longdesc lang="en">
Allow the container to be reused once it is stopped.  By default,
containers get removed once they are stopped.  Enable this option
to have the particular one persist when this happens.
</longdesc>
<shortdesc lang="en">reuse container</shortdesc>
<content type="boolean" default="${OCF_RESKEY_reuse_default}"/>
</parameter>

<parameter name="query_docker_health" required="0" unique="0">
<longdesc lang="en">
Query the builtin healthcheck of docker (v1.12+) to determine health of the
container. If left empty or set to false it will not be used.

The healthcheck itself has to be configured within docker, e.g. via
HEALTHCHECK in Dockerfile. This option just queries in what condition
docker considers the container to be and lets ocf do its thing accordingly.

Note that the time a container is in "starting" state counts against the
monitor timeout.

This is an additional check besides the standard check for the container
to be running, and the optional monitor_cmd check. It doesn't disable or
override them, so all of them (if used) have to come back healthy for the
container to be considered healthy.
</longdesc>
<shortdesc lang="en">use healthcheck</shortdesc>
<content type="boolean"/>
</parameter>

</parameters>

<actions>
<action name="start"        timeout="90s" />
<action name="stop"         timeout="90s" />
<action name="monitor"      timeout="30s" interval="30s" depth="0" />
<action name="meta-data"    timeout="5s" />
<action name="validate-all"   timeout="30s" />
</actions>
</resource-agent>
END
}

#######################################################################
REQUIRE_IMAGE_PULL=0

docker_usage()
{
	cat <<END
usage: $0 {start|stop|monitor|validate-all|meta-data}

Expects to have a fully populated OCF RA-compliant environment set.
END
}


monitor_cmd_exec()
{
	local rc=$OCF_SUCCESS
	local out

	if [ -z "$OCF_RESKEY_monitor_cmd" ]; then
		return $rc
	fi

	if docker exec --help >/dev/null 2>&1; then
		out=$(docker exec ${CONTAINER} $OCF_RESKEY_monitor_cmd 2>&1)
		rc=$?
	else
		out=$(echo "$OCF_RESKEY_monitor_cmd" | nsenter --target $(docker inspect --type=container --format {{.State.Pid}} ${CONTAINER}) --mount --uts --ipc --net --pid 2>&1)
		rc=$?
	fi

	if [ $rc -eq 127 ]; then
		ocf_log err "monitor cmd failed (rc=$rc), output: $out"
		ocf_exit_reason "monitor_cmd, ${OCF_RESKEY_monitor_cmd} , not found within container."
		# there is no recovering from this, exit immediately
		exit $OCF_ERR_ARGS
	elif [ $rc -ne 0 ]; then
		ocf_exit_reason "monitor cmd failed (rc=$rc), output: $out"
		rc=$OCF_ERR_GENERIC
	else
		ocf_log debug "monitor cmd passed: exit code = $rc"
	fi

	return $rc
}

container_exists()
{
	local err

	err=$(docker inspect --type=container $CONTAINER 2>&1 >/dev/null)

	if [ $? -ne $OCF_SUCCESS ]; then
		case $err in
			*"No such container"*)
				# Return failure instead of exiting if container does not exist
				return 1
				;;
			*)
				# Exit if error running command
				ocf_exit_reason "$err"
				exit $OCF_ERR_GENERIC
				;;
		esac
	fi

	return $OCF_SUCCESS
}

remove_container()
{
	if ocf_is_true "$OCF_RESKEY_reuse"; then
		# never remove the container if we have reuse enabled.
		return 0
	fi

	container_exists
	if [ $? -ne 0 ]; then
		# don't attempt to remove a container that doesn't exist
		return 0
	fi
	ocf_log notice "Cleaning up inactive container, ${CONTAINER}."
	ocf_run docker rm $CONTAINER
}

docker_simple_status()
{
	local val

	if [ ! -x "$(command -v docker)" ]; then 
		ocf_exit_reason "docker is not installed on this host"
		return $OCF_ERR_INSTALLED
	fi


	# let's first check if the daemon is up and running.
	VERSION_OUT=$(docker version)
	version_ret=$?
	if [ $version_ret -eq 1 ]; then
		ocf_exit_reason "Docker service is in error state while checking for ${CONTAINER}, based on image, ${OCF_RESKEY_image}: ${VERSION_OUT}"
		return $OCF_ERR_GENERIC
	fi

	container_exists
	if [ $? -ne 0 ]; then
		return $OCF_NOT_RUNNING
	fi

	# retrieve the 'Running' attribute for the container
	val=$(docker inspect --type=container --format {{.State.Running}} $CONTAINER 2>/dev/null)
	if [ $? -ne 0 ]; then
		#not running as a result of container not being found
		return $OCF_NOT_RUNNING
	fi

	if ocf_is_true "$val"; then
		# container exists and is running
		return $OCF_SUCCESS
	fi

	return $OCF_NOT_RUNNING
}

docker_health_status()
{

	if ocf_is_true "$OCF_RESKEY_query_docker_health"; then
                local val

                container_exists
                if [ $? -ne 0 ]; then
                        return $OCF_NOT_RUNNING
                fi

                # retrieve the 'Health' attribute for the container
                # This is a bash-style do-while loop to wait until instance is started.
                # if starting takes longer than monitor timeout then upstream will make this fail.
                while

                        val=$(docker inspect --type=container --format {{.State.Health.Status}} $CONTAINER 2>/dev/null)
                        if [ $? -ne 0 ]; then
                                #not healthy as a result of container not being found
                                return $OCF_NOT_RUNNING
                        fi
                        test "$val" = "starting"
                do

                        sleep 1
                done

                if [ "$val" = "healthy" ]; then
                        # container exists and is healthy
                        return $OCF_SUCCESS
                fi

                return $OCF_NOT_RUNNING
	fi

	return 0
}



docker_monitor()
{
	local rc=0

	docker_simple_status
	rc=$?

	if [ $rc -ne 0 ]; then
		return $rc
	fi

	docker_health_status
	rc=$?

	if [ $rc -ne 0 ]; then
		return $rc
	fi

	monitor_cmd_exec
}

docker_create_mounts() {
	oldIFS="$IFS"
	IFS=","
	for directory in $OCF_RESKEY_mount_points; do
		mkdir -p "$directory"
	done
	IFS="$oldIFS"
}

docker_start()
{
	docker_create_mounts
	local run_opts="-d --name=${CONTAINER}"
	# check to see if the container has already started
	docker_simple_status
	if [ $? -eq $OCF_SUCCESS ]; then
		return $OCF_SUCCESS
	fi

	if [ -n "$OCF_RESKEY_run_opts" ]; then
		run_opts="$run_opts $OCF_RESKEY_run_opts"
	fi

	if [ $REQUIRE_IMAGE_PULL -eq 1 ]; then
		ocf_log notice "Beginning pull of image, ${OCF_RESKEY_image}"
		docker pull "${OCF_RESKEY_image}"
		if [ $? -ne 0 ]; then
			ocf_exit_reason "failed to pull image ${OCF_RESKEY_image}"
			return $OCF_ERR_GENERIC
		fi
	fi

	if ocf_is_true "$OCF_RESKEY_reuse" && container_exists; then
		ocf_log info "starting existing container $CONTAINER."
		ocf_run docker start $CONTAINER
	else
		# make sure any previous container matching our container name is cleaned up first.
		# we already know at this point it wouldn't be running
		remove_container
		ocf_log info "running container $CONTAINER for the first time"
		ocf_run docker run $run_opts $OCF_RESKEY_image $OCF_RESKEY_run_cmd
	fi

	if [ $? -ne 0 ]; then
		ocf_exit_reason "docker failed to launch container"
		return $OCF_ERR_GENERIC
	fi


	# wait for monitor to pass before declaring that the container is started
	while true; do
		docker_simple_status
		if [ $? -ne $OCF_SUCCESS ]; then
			ocf_exit_reason "Newly created docker container exited after start"
			return $OCF_ERR_GENERIC
		fi

		monitor_cmd_exec
		if [ $? -eq $OCF_SUCCESS ]; then
			ocf_log notice "Container $CONTAINER  started successfully"
			return $OCF_SUCCESS
		fi

		ocf_exit_reason "waiting on monitor_cmd to pass after start"
		sleep 1
	done
}

docker_stop()
{
	local timeout=60
	docker_simple_status
	ret=$?
	if [ $ret -eq $OCF_NOT_RUNNING ]; then
		remove_container
		return $OCF_SUCCESS
        elif [ $ret -eq $OCF_ERR_GENERIC ]; then
               return $OCF_ERR_GENERIC
	fi

	if [ -n "$OCF_RESKEY_CRM_meta_timeout" ]; then
		timeout=$((($OCF_RESKEY_CRM_meta_timeout/1000) -10 ))
		if [ $timeout -lt 10 ]; then
			timeout=10
		fi
	fi

	if ocf_is_true "$OCF_RESKEY_force_kill"; then
		ocf_run docker kill $CONTAINER
	else
		ocf_log debug "waiting $timeout second[s] before killing container"
		ocf_run docker stop -t=$timeout $CONTAINER
	fi

	if [ $? -ne 0 ]; then
		ocf_exit_reason "Failed to stop container, ${CONTAINER}, based on image, ${OCF_RESKEY_image}."
		return $OCF_ERR_GENERIC
	fi

	remove_container
	if [ $? -ne 0 ]; then
		ocf_exit_reason "Failed to remove stopped container, ${CONTAINER}, based on image, ${OCF_RESKEY_image}."
		return $OCF_ERR_GENERIC
	fi

	return $OCF_SUCCESS
}

image_exists()
{
	# if no tag was specified, use default "latest"
	local COLON_FOUND=0
	local SLASH_FOUND=0
	local SERVER_NAME=""
	local IMAGE_NAME="${OCF_RESKEY_image}"
	local IMAGE_TAG="latest"

	SLASH_FOUND="$(echo "${OCF_RESKEY_image}" | grep -o '/' | grep -c .)"

	if [ ${SLASH_FOUND} -ge 1 ]; then
		SERVER_NAME="$(echo ${IMAGE_NAME} | cut -d / -f 1-${SLASH_FOUND})"
		IMAGE_NAME="$(echo ${IMAGE_NAME} | awk -F'/' '{print $NF}')"
	fi

	COLON_FOUND="$(echo "${IMAGE_NAME}" | grep -o ':' | grep -c .)"
	if [ ${COLON_FOUND} -ge 1 ]; then
		IMAGE_TAG="$(echo ${IMAGE_NAME} | awk -F':' '{print $NF}')"
		IMAGE_NAME="$(echo ${IMAGE_NAME} | cut -d : -f 1-${COLON_FOUND})"
	fi

	# IMAGE_NAME might be following formats:
	# - image
	# - repository:port/image
	# - docker.io/image (some distro will display "docker.io/" as prefix)
	docker images | awk '{print $1 ":" $2}' | egrep -q -s "^(docker.io\/|${SERVER_NAME}\/)?${IMAGE_NAME}:${IMAGE_TAG}\$"
	if [ $? -eq 0 ]; then
		# image found
		return 0
	fi

	if ocf_is_true "$OCF_RESKEY_allow_pull"; then
		REQUIRE_IMAGE_PULL=1
		ocf_log notice "Image (${OCF_RESKEY_image}) does not exist locally but will be pulled during start"
		return 0
	fi
	# image not found.
	return 1
}

docker_validate()
{
	check_binary docker
	if [ -z "$OCF_RESKEY_image" ]; then
		ocf_exit_reason "'image' option is required"
		exit $OCF_ERR_CONFIGURED
	fi

	if [ -n "$OCF_RESKEY_monitor_cmd" ]; then
		docker exec --help >/dev/null 2>&1
		if [ ! $? ]; then
			ocf_log info "checking for nsenter, which is required when 'monitor_cmd' is specified"
			check_binary nsenter
		fi
	fi

	image_exists
	if [ $? -ne 0 ]; then
		ocf_exit_reason "base image, ${OCF_RESKEY_image}, could not be found."
		exit $OCF_ERR_CONFIGURED
	fi

	return $OCF_SUCCESS
}

# TODO :
# When a user starts plural clones in a node in globally-unique, a user cannot appoint plural name parameters.
# When a user appoints reuse, the resource agent cannot connect plural clones with a container.

if ocf_is_true "$OCF_RESKEY_CRM_meta_globally_unique"; then
	if [ -n "$OCF_RESKEY_name" ]; then
		if [ -n "$OCF_RESKEY_CRM_meta_clone_node_max" ] && [ "$OCF_RESKEY_CRM_meta_clone_node_max" -ne 1 ]
		then
			ocf_exit_reason "Cannot make plural clones from the same name parameter."
			exit $OCF_ERR_CONFIGURED
		fi
		if [ -n "$OCF_RESKEY_CRM_meta_master_node_max" ] && [ "$OCF_RESKEY_CRM_meta_master_node_max" -ne 1 ]
		then
			ocf_exit_reason "Cannot make plural master from the same name parameter."
			exit $OCF_ERR_CONFIGURED
		fi
	fi
	: ${OCF_RESKEY_name=`echo ${OCF_RESOURCE_INSTANCE} | tr ':' '-'`} 
else 
	: ${OCF_RESKEY_name=${OCF_RESOURCE_INSTANCE}}
fi

if [ -n "$OCF_RESKEY_container" ]; then
	# we'll keep the container attribute around for a bit in order not to break
	# any existing deployments. The 'name' attribute is prefered now though.
	CONTAINER=$OCF_RESKEY_container
	ocf_log warn "The 'container' attribute is depreciated"
else
	CONTAINER=$OCF_RESKEY_name
fi

case $__OCF_ACTION in
meta-data) meta_data
		exit $OCF_SUCCESS;;
start)
	docker_validate
	docker_start;;
stop)		docker_stop;;
monitor)	docker_monitor;;
validate-all)	docker_validate;;
usage|help)	docker_usage
		exit $OCF_SUCCESS
		;;
*)		docker_usage
		exit $OCF_ERR_UNIMPLEMENTED
		;;
esac
rc=$?
ocf_log debug "${OCF_RESOURCE_INSTANCE} $__OCF_ACTION : $rc"
exit $rc