A dirty bash script to check the levels of a ledger with watermark; see the help guide on guides.railsbank.com for more context.

float-ledger-watermark-checker.sh

#! /usr/local/bin/bash

set -e
# set this to be your ledger's ledger_id
floatledgerid=some-ledger-uuid

# this is perhaps a little more than needed,
# but we use Keychain Access for our API Keys — it 
# has a simple interface that works in scripts
if [[ "$OSTYPE" == "darwin"* ]]; then
  # assumes our API key is stored in Mac's keychain
  export apikey=$(security find-generic-password -a ${USER} -s livekeys-for-railsbank -w) || echo "Can't find that"; exit 111
elif [ ! -e ${HOME}/livekeyfile ]; then
    echo "Can't find an API Key file (${HOME}/livekeyfile)!!"
    echo "Bye!"
    exit 222
  else
    export apikeystring=$(cat ~/playliveapikey)
    export apikey="API-Key $apikeystring"
fi

# now we have an API key we can do something
# first we assign our responses some variable names 
# and then hit curl parsing the response via jq (rather messily)
IFS=',' read -r ledgerid iban amount wmark < <(curl --silent -X \
    GET "https://live.railsbank.com/v1/customer/ledgers/${floatledgerid}" \
    -H "accept: application/json" \
    -H "Authorization: ${apikey}" | \
  jq '[.ledger_id, .iban, .amount, .ledger_meta.watermark] | @csv' --raw-output | \
  sed 's/"//g')

# in reviewing the script, you might find this line below useful?
# echo "Ledger ${ledgerid} (IBAN: ${iban}) has a \n balance of ${amount}. The watermark is ${wmark}"

# and here comes the maths
if (( $(echo "$amount > $wmark" | bc -l) )); then
    # echo "Watermark not reached"
    exit 0
  else
    echo "Watermark is reached. Fund the ledger"
    exit 1
fi