AWS Cloud Formation Precommit Validation

CloudFormationTemplateValidator.php

<?php

/**
 * Class CloudFormationTemplateValidator
 * @example
 *   echo 'Validating Cloud Formation Templates'.PHP_EOL;
 *   $hook = new CloudFormationTemplateValidator();
 *   $files = array_slice($argv, 1);                                           // Get a list of files from arguments
 *   $files = $files ?: $hook->getFilesRecursively('/^.+\.json$/i', getcwd()); // ...or recursively from the working dir
 *   if(!$hook->validateCloudFormationTemplates($files)) {
 *       exit(1);
 *   }
 */
class CloudFormationTemplateValidator
{

    protected $green = "\033[0;32m";
    protected $red = "\033[0;31m";
    protected $reset = "\033[0m";

    protected function red($string)
    {
        return $this->red . $string . $this->reset;
    }

    protected function green($string)
    {
        return $this->green . $string . $this->reset;
    }

    protected function echoLine($string, $endLine = true)
    {
        echo $string . ($endLine ? PHP_EOL : '');
    }

    public function getFilesRecursively($dir = null, $pattern = '/^.+$/i')
    {
        $dir = $dir ?: getcwd();
        $files = [];
        if(!$files) {
            $directoryIterator = new RecursiveDirectoryIterator($dir);
            $iteratorIterator = new RecursiveIteratorIterator($directoryIterator);
            $regexIterator = new RegexIterator($iteratorIterator, $pattern, RecursiveRegexIterator::GET_MATCH);
            foreach($regexIterator as $filesIterator) {
                foreach($filesIterator as $file) {
                    $files[] = $file;
                }
            }
        }
        return $files;
    }

    public function isAcfFile($fileName)
    {
        return substr($fileName, -5) === '.json';
    }

    public function getRealPathForFiles(array $files)
    {
        foreach($files as $key => $value) {
            $files[$key] = realpath($value);
            if (!$files[$key]) {
                throw new Exception("Invalid file '$value'");
            }
        }
    }

    public function validateCloudFormationTemplates($files)
    {
        foreach($files as $file) {
            if(!$this->isAcfFile($file)) {
                echo "Skipped: $file". PHP_EOL;
                continue;
            }
            $fileUrl = escapeshellarg("file://$file");
            $returnStatus = 0;
            $output = [];
            exec("aws cloudformation validate-template --template-body $fileUrl 2>&1", $output, $returnStatus);

            echo $returnStatus
                ? $this->red("Failure: ")   . $file . PHP_EOL
                : $this->green("Success: ") . $file . PHP_EOL
            ;

            if($returnStatus)
            {
                foreach($output as $line) {
                    echo $line.PHP_EOL;
                }
                return false;
            }
        }
        return true;
    }
}

pre-commit

#!/bin/sh

git diff --cached --name-status | awk '$1 != "D" { print $2 }' | xargs php `git rev-parse --show-toplevel`/bin/validate.php

validate.php

<?php

/**
 * @example Use this as a pre-commit hook
 *   #!/bin/sh
 *   git diff --cached --name-status | awk '$1 != "D" { print $2 }' | xargs php `git rev-parse --show-toplevel`/bin/validate.php
 */

require_once 'CloudFormationTemplateValidator.php';

echo 'Validating Cloud Formation Templates'.PHP_EOL;

$hook = new CloudFormationTemplateValidator();
$files = array_slice($argv, 1);                                     // Get a list of files from arguments
$files = $files ?: $hook->getFilesRecursively(getcwd()); // ...or recursively from the working dir
if(!$hook->validateCloudFormationTemplates($files)) {
    exit(1);
}