[SOLVED] get single line key value pair from json file using BASH for mongodb backup script

Issue

I have a config file located in ~/.config/server_config.json

this json file contains the following info:

{
    "server_name": "server1",
    "mongodb_url":"mongodb://user:password@localhost:27017/dbname"
    "other stuff": "stuff2"
}

I have a bash script that i use in a cronjob that will perform a mongodump daily, monthly, weekly, and do auto rotate backups, gzip, etc.

I want to be able to check this config file for the existence of the mongodb_url.

if exists, use that url that contains the username and password to pass into the mongodump script.

if the mongodb url does not exist in the json file, run the mongodump command normally using localhost with no authentication.

here is a snippet from the backup script

else # daily
    echo "Starting critical tables daily backup $(date)" >> $LOG_LOCATION
    for DATABASE in ${FULL_BACKUPS_ONLY_LIST//,/ }
        do
            for TABLE in ${CRITICAL_TABLES_LIST//,/ }
            do
                    echo "backing up $DATABASE $TABLE ..."
                    mongodump -d $DATABASE -c $TABLE --out $FINAL_BACKUP_DIR
            done
        done
fi

I basically want to be able to parse this json file to use the right mongodb url with username and password included.

im thinking about using python to first parse the json file, then send the url as an input argument into the bash script since parsing json with bash seems very difficult. Unless there is some sed/awk magic that can happen.

Solution

You can use jq bash command to parse the JSON file.

Sample test.json File Contents:

{
    "a": 1,
    "b": 2,
    "c": 4
}

bash command: jq '.b' test.json

Output: 2

Answered By - Bhima Rao Gogineni

Answer Checked By - Willingham (WPSolving Volunteer)