Extract PostgreSQL Credentials for a Pivotal Cloud Foundry App

getDBCredentials.sh

# * Extract PostgreSQL credentials from a bound service for use in this PCF app.
# ! Your manfiest file must bind the app to an existing PostgreSQL service via 'services'.
# @env VCAP_SERVICES        - The Cloud Foundry services this app is bound to. This is set automatically for you.
# @env POSTGRES_SERVICE     - The name of the specific PostgreSQL service to use. This is useful if your app is bound to multiple services.
# @env POSTGRES_SERVICE_KEY - The PostgreSQL service vendor key. Defaults to aws-rds-postgres for AWS.
# ? Reference: https://docs.cloudfoundry.org/devguide/deploy-apps/environment-variable.html#VCAP-SERVICES
function getDBCredentials {
    echo "[INFO] Extracting DB credentials from VCAP_SERVICES...";

    # Assume it is an AWS RDS PostgreSQL service if not specified.
    if [[ $POSTGRES_SERVICE_KEY == "" ]]; then POSTGRES_SERVICE_KEY="aws-rds-postgres"; fi

    if [ -z "$POSTGRES_SERVICE" ]; then
        echo "[WARN] var POSTGRES_SERVICE is not defined. Did you forget to include it in your vars.yml file?"\
            "Attempting to use the first, bound, PostgreSQL service if any.";
        CREDENTIALS=$(echo $VCAP_SERVICES | jq .\"${POSTGRES_SERVICE_KEY}\"[0].credentials);
    else
        echo "[INFO] POSTGRES_SERVICE is set to [ ${POSTGRES_SERVICE} ]. Attempting to extract credentials.";
        CREDENTIALS=$(echo $VCAP_SERVICES | jq -c ".\"${POSTGRES_SERVICE_KEY}\"[] | select(.name == \"${POSTGRES_SERVICE}\").credentials")
    fi

    if [[ -z "$POSTGRES_SERVICE" && -z "$CREDENTIALS" ]]; then
        echo "[ERROR] VCAP_SERVICES does not contain any PostgreSQL services."\
            "Did you forget to bind the service in your manfiest.yml file?";
        exit 2;
    elif [ -z "$CREDENTIALS" ]; then
        echo "[ERROR] VCAP_SERVICES does not contain the specified POSTGRES_SERVICE named [ ${POSTGRES_SERVICE} ]."\ 
            "Did you forget to bind the service in your manfiest.yml file? Maybe check for typos?";
        exit 2;
    fi

    DB_NAME=$(echo $CREDENTIALS | jq .database)
    DB_HOST=$(echo $CREDENTIALS | jq .hostname)
    DB_PORT=$(echo $CREDENTIALS | jq .port)
    DB_USERNAME=$(echo $CREDENTIALS | jq .username)
    DB_PASSWORD=$(echo $CREDENTIALS | jq .password)
    DB_URI=$(echo $CREDENTIALS | jq .uri)

    echo "[INFO] Sucessfully extracted the DB credentials."
}