Validation for Docker Services Startup

docker_services-validation

#!/bin/bash

#################################################
# Right now we are assuming you have already    #
# installed docker within your machine and your #
# current user belongs to docker system group   #
#################################################

#################
# ELASTICSEARCH #
#################

function elasticsearch_validate() {
        [[ `(curl -s http://localhost:"${ELASTICSEARCH_PORT}")` =~ "status" ]] && echo 0 || echo 1
}

function elasticsearch_start() {
        ELASTICSEARCH_ID=`docker run -d -P -t elasticsearch:1.4`
        ELASTICSEARCH_PORT=`docker port ${ELASTICSEARCH_ID} | cut -d':' -f2 | tr '\n' ' ' | cut -d ' ' -f1`
}


docker_start elasticsearch ${RETRIES}


#############
# CASSANDRA #
#############

function cassandra_validate() {
    STATUS=1
    set +e
    python -c "from cassandra.cluster import Cluster; cluster = Cluster(['localhost'], port=${CASSANDRA_PORT}); session = cluster.connect(); session.execute('SELECT now() FROM system.local;'); cluster.shutdown();"
    if [ ${?} -eq 0 ]; then
        STATUS=0
    fi
    set -e
    echo ${STATUS}
}

function cassandra_start() {
    CASSANDRA_ID=`docker run -d -P -t cassandra:2.1.6`
    CASSANDRA_PORT=`docker port ${CASSANDRA_ID} | grep 9042 | cut -d':' -f2 | tr '\n' ' ' | cut -d ' ' -f1`
}


docker_start cassandra     ${RETRIES}


##############
# POSTGRESQL #
##############

function postgres_validate {
    [[ `echo 'SELECT version();' | psql -U postgres -h localhost -p ${POSTGRES_PORT} template1` =~ "PostgreSQL" ]] && echo 0 || echo 1
}

function postgres_start {
    POSTGRES_ID=`docker run -d -P -t postgres:9.3`
    POSTGRES_PORT=`docker port ${POSTGRES_ID} | cut -d':' -f2`
}


docker_start postgres ${RETRIES}


#########
# Redis #
#########

function redis_validate {
    [[ `(echo PING; sleep 1) | nc localhost $REDIS_PORT` == $'+PONG\r' ]] && echo 0 || echo 1
}

function redis_start {
    REDIS_ID=`docker run -d -P -t redis:2.8`
    REDIS_PORT=`docker port ${REDIS_ID} | cut -d':' -f2`
}


docker_start redis ${RETRIES}


#############
# Docker up #
#############

function docker_start() {
    SERVICE=${1}
    RETRIES=${2}
        CURRENT_RETRIAL=0
        while [ ${CURRENT_RETRIAL} -lt ${RETRIES} ]; do
                ${SERVICE}_start
                CURRENT_VALIDATION=0
                VALIDATED=false
                while [ ${CURRENT_VALIDATION} -lt 20 ]; do
                        VALIDATION_RESULT=$(${SERVICE}_validate)
                        if [[ ${VALIDATION_RESULT} == 0 ]]
                        then
                                VALIDATED=true
                                echo 'Service is up.'
                                break
                        fi
                        echo 'Service not loaded, yet.'
                        CURRENT_VALIDATION=$((++CURRENT_VALIDATION))
                        sleep 1
                        CURRENT_VALIDATION=$((++CURRENT_VALIDATION))
                        sleep 1
                done
                if ${VALIDATED}; then
                        break
                fi
                CURRENT_RETRIAL=$((++CURRENT_RETRIAL))
                sleep 1
        done
        if ! ${VALIDATED}; then
                echo 'Failed while starting docker service.'
                exit 1
        fi
}

if [ -z ${RETRIES} ]; then
        RETRIES=3
fi