<?php
namespace Aws\CloudTrail;
use Aws\S3\S3Client;
use Aws\CloudTrail\Exception\CloudTrailException;
/**
* The `Aws\CloudTrail\LogFileIterator` provides an easy way to iterate over
* log file generated by AWS CloudTrail.
*
* CloudTrail log files contain data about your AWS API calls and are stored in
* Amazon S3 at a predictable path based on a bucket name, a key prefix, an
* account ID, a region, and date information. This class allows you to specify
* options, including a date range, and emits each log file that match the
* provided options.
*
* Yields an array containing the Amazon S3 bucket and key of the log file.
*/
class LogFileIterator extends \IteratorIterator
{
// For internal use
const DEFAULT_TRAIL_NAME = 'Default';
const PREFIX_TEMPLATE = 'prefix/AWSLogs/account/CloudTrail/region/date/';
const PREFIX_WILDCARD = '*';
// Option names used internally or externally
const TRAIL_NAME = 'trail_name';
const KEY_PREFIX = 'key_prefix';
const START_DATE = 'start_date';
const END_DATE = 'end_date';
const ACCOUNT_ID = 'account_id';
const LOG_REGION = 'log_region';
/** @var S3Client S3 client used to perform ListObjects operations */
private $s3Client;
/** @var string S3 bucket that contains the log files */
private $s3BucketName;
/**
* Constructs a LogRecordIterator. This factory method is used if the name
* of the S3 bucket containing your logs is not known. This factory method
* uses a CloudTrail client and the trail name (or "Default") to find the
* information about the trail necessary for constructing the
* LogRecordIterator.
*
* @param S3Client $s3Client
* @param CloudTrailClient $cloudTrailClient
* @param array $options
*
* @return LogRecordIterator
* @throws \InvalidArgumentException
* @see LogRecordIterator::__contruct
*/
public static function forTrail(
S3Client $s3Client,
CloudTrailClient $cloudTrailClient,
array $options = []
) {
$trailName = isset($options[self::TRAIL_NAME])
? $options[self::TRAIL_NAME]
: self::DEFAULT_TRAIL_NAME;
$s3BucketName = null;
// Use the CloudTrail client to get information about the trail,
// including the bucket name.
try {
$result = $cloudTrailClient->describeTrails([
'trailNameList' => [$trailName]
]);
$s3BucketName = $result->search('trailList[0].S3BucketName');
$options[self::KEY_PREFIX] = $result->search(
'trailList[0].S3KeyPrefix'
);
} catch (CloudTrailException $e) {
// There was an error describing the trail
}
// If the bucket name is still unknown, then throw an exception
if (!$s3BucketName) {
$prev = isset($e) ? $e : null;
throw new \InvalidArgumentException('The bucket name could not '
. 'be determined from the trail.', 0, $prev);
}
return new self($s3Client, $s3BucketName, $options);
}
/**
* Constructs a LogFileIterator using the specified options:
*
* - trail_name: The name of the trail that is generating our logs. If
* none is provided, then "Default" will be used, since that is the name
* of the trail created in the AWS Management Console.
* - key_prefix: The S3 key prefix of your log files. This value will be
* overwritten when using the `fromTrail()` method. However, if you are
* using the constructor, then this value will be used.
* - start_date: The timestamp of the beginning of date range of the log
* records you want to read. You can pass this in as a `DateTime` object,
* integer (unix timestamp), or a string compatible with `strtotime()`.
* - end_date: The timestamp of the end of date range of the log records
* you want to read. You can pass this in as a `DateTime` object, integer
* (unix timestamp), or a string compatible with `strtotime()`.
* - account_id: This is your AWS account ID, which is the 12-digit number
* found on the *Account Identifiers* section of the *AWS Security
* Credentials* page. See https://console.aws.amazon.com/iam/home?#security_credential
* - log_region: Region of the services of the log records you want to read.
*
* @param S3Client $s3Client
* @param string $s3BucketName
* @param array $options
*/
public function __construct(
S3Client $s3Client,
$s3BucketName,
array $options = []
) {
$this->s3Client = $s3Client;
$this->s3BucketName = $s3BucketName;
parent::__construct($this->buildListObjectsIterator($options));
}
/**
* An override of the typical current behavior of \IteratorIterator to
* format the output such that the bucket and key are returned in an array
*
* @return array|bool
*/
public function current()
{
if ($object = parent::current()) {
return [
'Bucket' => $this->s3BucketName,
'Key' => $object['Key']
];
}
return false;
}
/**
* Constructs an S3 ListObjects iterator, optionally decorated with
* FilterIterators, based on the provided options.
*
* @param array $options
*
* @return \Iterator
*/
private function buildListObjectsIterator(array $options)
{
// Extract and normalize the date values from the options
$startDate = isset($options[self::START_DATE])
? $this->normalizeDateValue($options[self::START_DATE])
: null;
$endDate = isset($options[self::END_DATE])
? $this->normalizeDateValue($options[self::END_DATE])
: null;
// Determine the parts of the key prefix of the log files being read
$parts = [
'prefix' => isset($options[self::KEY_PREFIX])
? $options[self::KEY_PREFIX]
: null,
'account' => isset($options[self::ACCOUNT_ID])
? $options[self::ACCOUNT_ID]
: self::PREFIX_WILDCARD,
'region' => isset($options[self::LOG_REGION])
? $options[self::LOG_REGION]
: self::PREFIX_WILDCARD,
'date' => $this->determineDateForPrefix($startDate, $endDate),
];
// Determine the longest key prefix that can be used to retrieve all
// of the relevant log files.
$candidatePrefix = ltrim(strtr(self::PREFIX_TEMPLATE, $parts), '/');
$logKeyPrefix = $candidatePrefix;
$index = strpos($candidatePrefix, self::PREFIX_WILDCARD);
if ($index !== false) {
$logKeyPrefix = substr($candidatePrefix, 0, $index);
}
// Create an iterator that will emit all of the objects matching the
// key prefix.
$objectsIterator = $this->s3Client->getIterator('ListObjects', [
'Bucket' => $this->s3BucketName,
'Prefix' => $logKeyPrefix,
]);
// Apply regex and/or date filters to the objects iterator to emit only
// log files matching the options.
$objectsIterator = $this->applyRegexFilter(
$objectsIterator,
$logKeyPrefix,
$candidatePrefix
);
$objectsIterator = $this->applyDateFilter(
$objectsIterator,
$startDate,
$endDate
);
return $objectsIterator;
}
/**
* Normalizes a date value to a unix timestamp
*
* @param string|\DateTime|int $date
*
* @return int
* @throws \InvalidArgumentException if the value cannot be converted to
* a timestamp
*/
private function normalizeDateValue($date)
{
if (is_string($date)) {
$date = strtotime($date);
} elseif ($date instanceof \DateTime) {
$date = $date->format('U');
} elseif (!is_int($date)) {
throw new \InvalidArgumentException('Date values must be a '
. 'string, an int, or a DateTime object.');
}
return $date;
}
/**
* Uses the provided date values to determine the date portion of the prefix
*/
private function determineDateForPrefix($startDate, $endDate)
{
// The default date value should look like "*/*/*" after joining
$dateParts = array_fill_keys(['Y', 'm', 'd'], self::PREFIX_WILDCARD);
// Narrow down the date by replacing the WILDCARDs with values if they
// are the same for the start and end date.
if ($startDate && $endDate) {
foreach ($dateParts as $key => &$value) {
$candidateValue = date($key, $startDate);
if ($candidateValue === date($key, $endDate)) {
$value = $candidateValue;
} else {
break;
}
}
}
return join('/', $dateParts);
}
/**
* Applies a regex iterator filter that limits the ListObjects result set
* based on the provided options.
*
* @param \Iterator $objectsIterator
* @param string $logKeyPrefix
* @param string $candidatePrefix
*
* @return \Iterator
*/
private function applyRegexFilter(
$objectsIterator,
$logKeyPrefix,
$candidatePrefix
) {
// If the prefix and candidate prefix are not the same, then there were
// WILDCARDs.
if ($logKeyPrefix !== $candidatePrefix) {
// Turn the candidate prefix into a regex by trimming and
// converting WILDCARDs to regex notation.
$regex = rtrim($candidatePrefix, '/' . self::PREFIX_WILDCARD) . '/';
$regex = strtr($regex, [self::PREFIX_WILDCARD => '[^/]+']);
// After trimming WILDCARDs or the end, if the regex is the same as
// the prefix, then no regex is needed.
if ($logKeyPrefix !== $regex) {
// Apply a regex filter iterator to remove files that don't
// match the provided options.
$objectsIterator = new \CallbackFilterIterator(
$objectsIterator,
function ($object) use ($regex) {
return preg_match("#{$regex}#", $object['Key']);
}
);
}
}
return $objectsIterator;
}
/**
* Applies an iterator filter to restrict the ListObjects result set to the
* specified date range.
*
* @param \Iterator $objectsIterator
* @param int $startDate
* @param int $endDate
*
* @return \Iterator
*/
private function applyDateFilter($objectsIterator, $startDate, $endDate)
{
// If either a start or end date was provided, filter out dates that
// don't match the date range.
if ($startDate || $endDate) {
$fn = function ($object) use ($startDate, $endDate) {
if (!preg_match('/[0-9]{8}T[0-9]{4}Z/', $object['Key'], $m)) {
return false;
}
$date = strtotime($m[0]);
return (!$startDate || $date >= $startDate)
&& (!$endDate || $date <= $endDate);
};
$objectsIterator = new \CallbackFilterIterator($objectsIterator, $fn);
}
return $objectsIterator;
}
}
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