Fix ENV bridge configuration for emqx-edge docker

[woosteln]

• [ * ] BUG REPORT
• [ * ] FEATURE REQUEST

---

FEATURE REQUEST

Missing feature

Bridge configuration on emqx-edge docker containers seems to be either missing or broken, or patchy.

If would be great to be able to specify bridge configuration with environment variables in docker run command and have them override any bridge template ( eg. the default bridge.aws.X configuration in the /opt/emqx/etc/plugins/emqx_bridge_mqtt.conf file

Justification

This feature used to work in previous versions of docker containers, but due to new layout of plugin files and parsing ( and an assumption of the aws namespace of the bridge ) it seems to have mixed results at best.

As many bridges as the user wants could be configured with some improvement in the docker-enttrypoint.sh.

Workarounds

Custom docker build of emqx-edge with following Dockerfile and docker-entrypoint.sh

Dockerfile

FROM emqx/emqx-edge:v3.2.2
COPY docker-entrypoint.sh /usr/bin/docker-entrypoint.sh
ENTRYPOINT ["/usr/bin/docker-entrypoint.sh"]
CMD ["/usr/bin/start.sh"]

docker-entrypoint.sh

#!/bin/sh
## EMQ docker image start script
# Huang Rui <vowstar@gmail.com>
# EMQ X Team <support@emqx.io>

## Shell setting
if [[ ! -z "$DEBUG" ]]; then
    set -ex
else
    set -e
fi

## Local IP address setting

LOCAL_IP=$(hostname -i |grep -E -oh '((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])'|head -n 1)

## EMQ Base settings and plugins setting
# Base settings in /opt/emqx/etc/emqx.conf
# Plugin settings in /opt/emqx/etc/plugins

_EMQX_HOME="/opt/emqx"

if [[ -z "$PLATFORM_ETC_DIR" ]]; then
    export PLATFORM_ETC_DIR="$_EMQX_HOME/etc"
fi

if [[ -z "$PLATFORM_LOG_DIR" ]]; then
    export PLATFORM_LOG_DIR="$_EMQX_HOME/log"
fi

if [[ -z "$EMQX_NAME" ]]; then
    export EMQX_NAME="$(hostname)"
fi

if [[ -z "$EMQX_HOST" ]]; then
    case $EMQX_CLUSTER__K8S__ADDRESS_TYPE in
        "dns")
            DNSAddress="${LOCAL_IP//./-}.${EMQX_CLUSTER__K8S__NAMESPACE}.pod.cluster.local"
            export EMQX_HOST="$DNSAddress"
            ;;
        "hostname")
            DNSAddress=$(sed -n "/^${LOCAL_IP}/"p /etc/hosts | grep -e "$(hostname).*.${EMQX_CLUSTER__K8S__NAMESPACE}.svc.cluster.local" -o)
            export EMQX_HOST="$DNSAddress"
            ;;
        *)
            export EMQX_HOST="$LOCAL_IP"
            ;;
    esac
fi

if [[ -z "$EMQX_WAIT_TIME" ]]; then
    export EMQX_WAIT_TIME=5
fi

if [[ -z "$EMQX_NODE__NAME" ]]; then
    export EMQX_NODE__NAME="$EMQX_NAME@$EMQX_HOST"
fi

# Set hosts to prevent cluster mode failed

# unset EMQX_NAME
# unset EMQX_HOST

if [[ -z "$EMQX_NODE__PROCESS_LIMIT" ]]; then
    export EMQX_NODE__PROCESS_LIMIT=2097152
fi

if [[ -z "$EMQX_NODE__MAX_PORTS" ]]; then
    export EMQX_NODE__MAX_PORTS=1048576
fi

if [[ -z "$EMQX_NODE__MAX_ETS_TABLES" ]]; then
    export EMQX_NODE__MAX_ETS_TABLES=2097152
fi

if [[ -z "$EMQX__LOG_CONSOLE" ]]; then
    export EMQX__LOG_CONSOLE="console"
fi

if [[ -z "$EMQX_LISTENER__TCP__EXTERNAL__ACCEPTORS" ]]; then
    export EMQX_LISTENER__TCP__EXTERNAL__ACCEPTORS=64
fi

if [[ -z "$EMQX_LISTENER__TCP__EXTERNAL__MAX_CLIENTS" ]]; then
    export EMQX_LISTENER__TCP__EXTERNAL__MAX_CLIENTS=1000000
fi

if [[ -z "$EMQX_LISTENER__SSL__EXTERNAL__ACCEPTORS" ]]; then
    export EMQX_LISTENER__SSL__EXTERNAL__ACCEPTORS=32
fi

if [[ -z "$EMQX_LISTENER__SSL__EXTERNAL__MAX_CLIENTS" ]]; then
    export EMQX_LISTENER__SSL__EXTERNAL__MAX_CLIENTS=500000
fi

if [[ -z "$EMQX_LISTENER__WS__EXTERNAL__ACCEPTORS" ]]; then
    export EMQX_LISTENER__WS__EXTERNAL__ACCEPTORS=16
fi

if [[ -z "$EMQX_LISTENER__WS__EXTERNAL__MAX_CLIENTS" ]]; then
    export EMQX_LISTENER__WS__EXTERNAL__MAX_CLIENTS=250000
fi

# Fix issue #42 - export env EMQX_DASHBOARD__DEFAULT_USER__PASSWORD to configure
# 'dashboard.default_user.password' in etc/plugins/emqx_dashboard.conf
if [[ ! -z "$EMQX_ADMIN_PASSWORD" ]]; then
    export EMQX_DASHBOARD__DEFAULT_USER__PASSWORD=$EMQX_ADMIN_PASSWORD
fi

# Catch all EMQX_ prefix environment variable and match it in configure file
CONFIG="${_EMQX_HOME}/etc/emqx.conf"
CONFIG_PLUGINS="${_EMQX_HOME}/etc/plugins"
CONFIG_MQTT_BRIDGE_PLUGIN="${_EMQX_HOME}/etc/plugins/emqx_bridge_mqtt.conf"

# If Bridge plugin configuration detected in env
# then remove any existing config
if [[ "$(echo $(env) | grep -E 'EMQX_BRIDGE__MQTT__')" ]]; then
    echo "Cleaning bridge config"
    echo "" > $CONFIG_MQTT_BRIDGE_PLUGIN
fi

for VAR in $(env)
do
    # Config normal keys such like node.name = emqx@127.0.0.1
    if [[ ! -z "$(echo $VAR | grep -E '^EMQX_')" ]]; then
        VAR_NAME=$(echo "$VAR" | sed -r "s/EMQX_([^=]*)=.*/\1/g" | tr '[:upper:]' '[:lower:]' | sed -r "s/__/\./g")
        VAR_FULL_NAME=$(echo "$VAR" | sed -r "s/([^=]*)=.*/\1/g")
        # Config in emq.conf
        if [[ ! -z "$(cat $CONFIG |grep -E "^(^|^#*|^#*\s*)$VAR_NAME")" ]]; then
            echo "$VAR_NAME=$(eval echo \$$VAR_FULL_NAME)"
            echo "$(sed -r "s/(^#*\s*)($VAR_NAME)\s*=\s*(.*)/\2 = $(eval echo \$$VAR_FULL_NAME|sed -e 's/\//\\\//g')/g" $CONFIG)" > $CONFIG   
        fi
        # Config in plugins/*
        for CONFIG_PLUGINS_FILE in $(ls $CONFIG_PLUGINS); do
            if [[ ! -z "$(cat $CONFIG_PLUGINS/$CONFIG_PLUGINS_FILE |grep -E "^(^|^#*|^#*\s*)$VAR_NAME")" ]]; then
                echo "$VAR_NAME=$(eval echo \$$VAR_FULL_NAME)"
                echo "$(sed -r "s/(^#*\s*)($VAR_NAME)\s*=\s*(.*)/\2 = $(eval echo \$$VAR_FULL_NAME|sed -e 's/\//\\\//g')/g" $CONFIG_PLUGINS/$CONFIG_PLUGINS_FILE)" > $CONFIG_PLUGINS/$CONFIG_PLUGINS_FILE
            fi 
        done
        # MQTT Bridge configurations
        if [[ "$(echo $VAR_FULL_NAME | grep -E '^EMQX_BRIDGE__MQTT__')" ]]; then
            echo "$VAR_NAME=$(eval echo \$$VAR_FULL_NAME)"
            echo "$VAR_NAME=$(eval echo \$$VAR_FULL_NAME)" >> $CONFIG_MQTT_BRIDGE_PLUGIN
        fi
    fi
    
    # Config template such like {{ platform_etc_dir }}
    if [[ ! -z "$(echo $VAR | grep -E '^PLATFORM_')" ]]; then
        echo "$VAR_NAME=$(eval echo \$$VAR_FULL_NAME)"
        VAR_NAME=$(echo "$VAR" | sed -r "s/([^=]*)=.*/\1/g"| tr '[:upper:]' '[:lower:]')
        VAR_FULL_NAME=$(echo "$VAR" | sed -r "s/([^=]*)=.*/\1/g")
        echo "$(sed -r "s@\{\{\s*$VAR_NAME\s*\}\}@$(eval echo \$$VAR_FULL_NAME|sed -e 's/\//\\\//g')@g" $CONFIG)" > $CONFIG
    fi
done

## EMQ Plugin load settings
# Plugins loaded by default

if [[ ! -z "$EMQX_LOADED_PLUGINS" ]]; then
    echo "EMQX_LOADED_PLUGINS=$EMQX_LOADED_PLUGINS"
    # First, remove special char at header
    # Next, replace special char to ".\n" to fit emq loaded_plugins format
    echo $(echo "$EMQX_LOADED_PLUGINS."|sed -e "s/^[^A-Za-z0-9_]\{1,\}//g"|sed -e "s/[^A-Za-z0-9_]\{1,\}/\. /g")|tr ' ' '\n' > /opt/emqx/data/loaded_plugins
fi

exec "$@"

The crucial lines are:

# If Bridge plugin configuration detected in env
# then remove any existing config
if [[ "$(echo $(env) | grep -E 'EMQX_BRIDGE__MQTT__')" ]]; then
    echo "Cleaning bridge config"
    echo "" > $CONFIG_MQTT_BRIDGE_PLUGIN
fi

Which detects if any bridge configuration is specified on the environment. In which case it cleans out any default configuration present in the plugins conif dir, assuming ( because bridges exist in custom namespaces ) that any pre-existing configuration will not be relevant.

It also makes an assumption that all necessary bridge configuration vars will be provided by environment.

        # MQTT Bridge configurations
        if [[ "$(echo $VAR_FULL_NAME | grep -E '^EMQX_BRIDGE__MQTT__')" ]]; then
            echo "$VAR_NAME=$(eval echo \$$VAR_FULL_NAME)"
            echo "$VAR_NAME=$(eval echo \$$VAR_FULL_NAME)" >> $CONFIG_MQTT_BRIDGE_PLUGIN
        fi

Which appends all bridge related configuration key=value pairs to the bridge plugin configuration file.