Watch and Diff. A shell script for monitoring changes in configuration files

watch-and-diff.sh

#!/usr/bin/env bash

set -euo pipefail

function __get_missing_keys {
    php -- "$@" << 'EOF'
<?php

$args = $GLOBALS['argv'];
array_shift($args);

foreach ($args as $path) {
    if (file_exists($path)) {
        include $path;
    }
}

$expected = [
    'allowedSAs'           => null,
    'clientId'             => null,
    'clientSecret'         => null,
    'cloudConsoleRoutes'   => null,
    'cloudConsoleUrl'      => null,
    'crmOAuthScope'        => null,
    'enabled'              => null,
    'idpUrl'               => null,
    'requestedOAuthScopes' => null,
    'stsKeySetId'          => null,
    'stsUrl'               => null,
    'tid'                  => null,
];

$actual = array_intersect_key($sugar_config['idm_mode'] ?? [], $expected);

$diff = array_diff_key($expected, $actual);

if ($diff) {
    echo implode(PHP_EOL, array_keys($diff)), PHP_EOL;

    exit(1);
}
EOF
}

ALERT_EMAIL=""
ALERT_SENT=0

if [ "$1" == "-e" ]; then
    ALERT_EMAIL="$2"
    shift 2
fi

if [ $# -lt 1 ]; then
    echo "Usage: $(basename $0) [-e alert@example.com] <file>..." >&2
    exit 1;
fi

declare -A CONTENTS

for FILE in "$@"
do
    CONTENTS["$FILE"]=$(<"$FILE")
done

while FILE=`inotifywait -e close_write,move_self,delete_self --format "%w" "$@"`
do
    diff -u <(echo -n "${CONTENTS["$FILE"]}") "$FILE" || true
    CONTENTS["$FILE"]=$(<"$FILE")
    echo

    MISSING_KEYS=$(__get_missing_keys "$@") || {
        echo "The following configuration keys are missing:"
        echo "$MISSING_KEYS"
        echo

        if [ ! -z "$ALERT_EMAIL" -a $ALERT_SENT -ne 1 ]; then
            echo "Sending alert to $ALERT_EMAIL"
            {
                echo "Instance path: $(dirname $FILE)"
                echo "Missing keys:"
                echo "$MISSING_KEYS"
            } | mail -s "Missing configuration keys" $ALERT_EMAIL && ALERT_SENT=1
        fi
    }
done