Script to update the hosts file according to the container names in a docker-compose setup

docker-compose-start.php

<?php

define('HOST_SUFFIX', '.local');

/**
 * @return string[]
 */
function determineIpAddresses()
{
    $lines = array_slice(explode(PHP_EOL, shell_exec('docker-compose ps')), 2, -1);
    $ipAddresses = [];
    foreach ($lines as $line) {
        $container = explode(' ', $line, 2)[0];
        $information = json_decode(shell_exec("docker inspect $container"), true)[0];
        $ipAddresses[$container] = array_values($information['NetworkSettings']['Networks'])[0]['IPAddress'];
    }
    return $ipAddresses;
}

/**
 * @param string[] $lines
 * @param string[] $containers
 * @return string[]
 */
function filterContainers($lines, $containers)
{
    $hostSuffix = strlen(HOST_SUFFIX);
    $filteredLines = [];
    foreach ($lines as $line) {
        if (substr($line, -$hostSuffix) !== HOST_SUFFIX) {
            $filteredLines[] = $line;
            continue;
        }

        $parts = preg_split('/[\t ]+/', $line);
        $ipAddress = $parts[0];
        $hosts = array_filter(array_slice($parts, 1));
        foreach ($hosts as $index => $host) {
            $container = substr($host, 0, -$hostSuffix);
            if (in_array($container, $containers, true)) {
                unset($hosts[$index]);
            }
        }

        if ($hosts !== []) {
            $filteredLines[] = buildHostLine($ipAddress, $hosts);
        }
    }
    return $filteredLines;
}

/**
 * @param string $ipAddress
 * @param string[] $hosts
 * @return string
 */
function buildHostLine($ipAddress, $hosts)
{
    return $ipAddress . "\t" . implode(' ', $hosts);
}

/**
 * @param string[] $ipAddresses
 * @return string[]
 */
function generateHostLines($ipAddresses)
{
    $lines = [];
    foreach($ipAddresses as $container => $ipAddress) {
        $lines[] = buildHostLine($ipAddress, [$container . HOST_SUFFIX]);
    }
    return $lines;
}


echo shell_exec('docker-compose start');
$ipAddresses = determineIpAddresses();
$filteredHostFile = filterContainers(file('/etc/hosts', FILE_IGNORE_NEW_LINES), array_keys($ipAddresses));
$lines = array_merge($filteredHostFile, generateHostLines($ipAddresses));
file_put_contents('/etc/hosts', implode(PHP_EOL, $lines) . PHP_EOL);