Dislog

Dislog is an API call logger. API calls differ from normal log events because they compose of a request and a response which happen at different times however should be logged together as they are related.

Framework integration

Symfony - DislogBundle

Usage

LoggingHttpClientInterface

A PSR-18 compatible LoggingHttpClient is provided if recording HTTP requests from a Psr\Http\Client\ClientInterface.

Note: if using Assimtech\Dislog\LoggingHttpClient you MUST install the following dependancies into your project:

• guzzlehttp/psr7 This is only used to translate Psr\Http\Message{RequestInterface,ResponseInterface} into strings
• psr/http-client
• psr/http-message

/**
 * @var Psr\Http\Client\ClientInterface $httpClient
 * @var Assimtech\Dislog\ApiCallLoggerInterface $apiCallLogger
 */
$loggingHttpClient = new Assimtech\Dislog\LoggingHttpClient(
    $httpClient,
    $apiCallLogger
);

/**
 * @var Psr\Http\Message\ResponseInterface $response
 */
$response = $loggingHttpClient->sendRequest(
    /* Psr\Http\Message\RequestInterface */ $request,
    /* ?string */ $appMethod = null, // The method in the application that triggered this API call, setting to null will disable API logging
    /* ?string */ $reference = null, // The reference for this specific call (e.g. id or key if available), helps with searching API logs
    /* callable[]|callable|null */ $requestProcessors = null, // Processors to apply to $request, see Processors section below
    /* callable[]|callable|null */ $responseProcessors = null, // Processors to apply to $response, see Processors section below
    /* bool */ $omitPayload = false, // If set to true, request/response will not be logged however metadata will, useful for monitoring without logging full request or response
);

Payload omission

If you only want to log metadata (everything except for the raw request / response) on certain responses you can use $omitPayload. If you decide after making the API call you DO want to log the raw request / response you may force the payload to be logged.

$response = $loggingHttpClient->sendRequest(
    $request,
    $appMethod,
    $reference,
    $requestProcessors,
    $responseProcessors,
    true, // $omitPayload - Do not log raw request / response but still log all other metadata, this allows us to still monitor api calls
);
if (200 !== $response->getStatusCode()) {
    $loggingHttpClient->logLastPayload();
}

ApiCallLogger

The ApiCallLogger may be used to record requests and responses to both client and server side apis. Request and response payloads are both optional. If you are recording an FTP file upload, there may not be a response on successful upload. You would still invoke logResponse however to indicate the server accepted the file.

/**
 * @var Assimtech\Dislog\ApiCallLoggerInterface $apiCallLogger
 * @var Assimtech\Dislog\Model\ApiCallInterface $apiCall
 */
$apiCall = $apiCallLogger->logRequest(
    /* ?string */ $request,
    /* ?string */ $endpoint,
    /* ?string */ $appMethod,
    /* ?string */ $reference,
    /* callable[]|callable|null */ $processors
);

$response = $api->transmit($request);

$this->apiCallLogger->logResponse($apiCall, $response);

Here's an example of dislog in a fake Api:

use Assimtech\Dislog;

class Api
{
    protected $apiLogger;

    public function __construct(Dislog\ApiCallLoggerInterface $apiCallLogger)
    {
        $this->apiCallLogger = $apiCallLogger;
    }

    public function transmit($request)
    {
        return '<some response />';
    }

    public function doSomething()
    {
        $request = '<some request />';
        $endpoint = 'http://my.endpoint';
        $reference = time();

        $apiCall = $this->apiCallLogger->logRequest(
            $request,
            $endpoint,
            __METHOD__,
            $reference
        );

        $response = $this->transmit($request);

        $this->apiCallLogger->logResponse(
            $apiCall,
            $response
        );
    }
}

$stream = fopen('/tmp/my.log', 'a');
$uniqueIdentity = new Dislog\Identity\UniqueIdGenerator();
$stringSerializer = new Dislog\Serializer\StringSerializer();
$streamHandler = new Dislog\Handler\Stream($stream, $uniqueIdentity, $stringSerializer);
$apiCallFactory = new Dislog\Factory\ApiCallFactory();
$apiCallLogger = new Dislog\ApiCallLogger($apiCallFactory, $streamHandler);

$api = new Api($apiCallLogger);
$api->doSomething();

Old logs can be cleaned up by calling remove on supporting handlers:

$handler->remove(60 * 60 * 24 * 30); // keep 30 days worth of logs

Handlers

Stream

This handler accepts a writable stream resource. You must also give it an identity generator and a serializer.

use Assimtech\Dislog;

$stream = fopen('/tmp/my.log', 'a');
$uniqueIdentity = new Dislog\Identity\UniqueIdGenerator();
$stringSerializer = new Dislog\Serializer\StringSerializer();

$streamHandler = new Dislog\Handler\Stream($stream, $uniqueIdentity, $stringSerializer);

DoctrineDocumentManager

This handler accepts a Doctrine\ODM\MongoDB\DocumentManager.

Note: You must setup any mapping to an Assimtech\Dislog\Model\ApiCallInterface in your document manager WARNING: It is advisable to avoid using your application's default document manager as a flush() from dislog may interfere with your application

$documentHandler = new Dislog\Handler\DoctrineDocumentManager($documentManager);

DoctrineEntityManager

This handler accepts a Doctrine\ORM\EntityManagerInterface.

Note: You must setup any mapping to an Assimtech\Dislog\Model\ApiCallInterface in your entity manager WARNING: It is advisable to avoid using your application's default entity manager as a flush() from dislog may interfere with your application

$entityHandler = new Dislog\Handler\DoctrineEntityManager($entityManager);

Processors

A processor is a callable which is executed on either the request or response payload. They can be used for modifying the request or response before the ApiCall is handled. An example might be to mask credit card numbers or obfuscate a password.

Processors are passed along with the logRequest and / or logResponse calls to process the appropriate payload.

Note: Processors are not invoked on a null request / response.

function getMaskedCard($card)
{
    $firstSix = substr($card, 0, 6);
    $lastFour = substr($card, -4);
    $middle = str_repeat('*', strlen($card) - 10);
    return $firstSix . $middle . $lastFour;
}

$endpoint = 'https://my.endpoint';
$appMethod = 'processPayment';
$reference = time();
$card = '4444333322221111';
$cvv = '123';
$request = json_encode([
    'amount' => 12.95,
    'card' => $card,
    'expiry' => '2021-04',
    'cvv' => $cvv,
]);

$maskCard = function ($request) use ($card) {
    $maskedCard = getMaskedCard($card);
    return str_replace($card, $maskedCard, $request);
};
$obfuscateCvv = function ($request) use ($cvv) {
    return str_replace($cvv, '***', $request);
};
$apiCallLogger->logRequest(
    $request,
    $endpoint,
    $appMethod,
    $reference,
    [
        $maskCard,
        $obfuscateCvv,
    )
);

StringReplace

This processor is based on php's str_replace. It will replace a known string in a request / response.

$maskedCard = getMaskedCard($card);
$obfuscatedCvv = '***';
$stringReplace = new Assimtech\Dislog\Processor\StringReplace([
    $card,
    $cvv,
], [
    $maskedCard,
    $obfuscatedCvv,
]);
$apiCallLogger->logRequest(
    $request,
    $endpoint,
    $appMethod,
    $reference,
    $stringReplace
);

RegexReplace

This processor is based on php's preg_replace. It will replace a regex in a request / response.

$response = '{social_security_number: "1234567890"}';
$regexReplace = new Assimtech\Dislog\Processor\RegexReplace(
    '/social_security_number: "(\d\d)\d+(\d\d)"/',
    'social_security_number: "$1***$2"'
);
$apiCallLogger->logResponse(
    $apiCall,
    $response,
    $regexReplace
);

Serializers

A Serializer is a callable which converts an ApiCall into something a handler can deal with. Not all handers need to be paired with a Serializer and can deal with a raw ApiCall (e.g. DoctrineObjectManager).