How to add API logging for Kiwi TCMS

Posted by Alexander Todorov on Fri 07 September 2018 under customization

In this blog post I will show more ways to customize Kiwi TCMS by adding logging capabilities to the API backend. Indeed this is a feature that our team deemed not required for upstream and was removed in PR #436.

Start by creating the following directory structure:

    api_logging/
        __init__.py
        handlers.py
        models.py

This is a small Django application that will log every call to the API backend. Each file looks like this:

    # models.py contains DB schema for your new table
    from django.db import models
    from django.conf import settings

    class ApiCallLog(models.Model):
        executed_at = models.DateTimeField(auto_now_add=True)
        user = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, blank=True,
                                 on_delete=models.CASCADE)
        method = models.CharField(max_length=255)
        args = models.TextField(blank=True)

        def __str__(self):
            return "%s: %s" % (self.user, self.method)

Then

    # handlers.py overrides the RPC handlers coming from django-modernrpc
    from modernrpc import handlers

    from django.conf import settings
    from django.contrib.auth import get_user_model

    from .models import ApiCallLog

    def log_call(request, method_name, args):
        """ Log an RPC call to the database or stdout in DEBUG mode. """
        request_user = request.user
        if not request_user.is_authenticated:
            # create an anonymous user object for logging purposes
            request_user, _ = get_user_model().objects.get_or_create(
                username='Anonymous',
                is_active=False)

        if method_name is None:
            method_name = '--- method_name missing ---'

        if settings.DEBUG:
            print('API call:: user: {0}, method: {1}, args: {2}'.format(
                request_user,
                method_name,
                args))
        else:
            ApiCallLog.objects.create(
                user=request_user,
                method=method_name,
                args=str(args))

    class XMLRPCHandler(handlers.XMLRPCHandler):
        def process_request(self):
            encoding = self.request.encoding or 'utf-8'
            data = self.request.body.decode(encoding)
            params, method_name = self.loads(data)

            log_call(self.request, method_name, params)
            return super().process_request()

    class JSONRPCHandler(handlers.JSONRPCHandler):
        def process_single_request(self, payload):
            method_name = payload.get('method', None)
            params = payload.get('params')

            log_call(self.request, method_name, params)
            return super().process_single_request(payload)

NOTE: You will have to execute ./manage.py makemigrations api_logging to create the initial migration for Django. This could be easier if you place the above directory into existing Django application or craft the migration file by hand!

The last thing you want to do is create a local_settings.py file which will override Kiwi TCMS defaults:

    # local_settings.py
    from django.conf import settings

    settings.INSTALLED_APPS += [
        'api_logging',
    ]

    MODERNRPC_HANDLERS = ['api_logging.handlers.XMLRPCHandler',
                          'api_logging.handlers.JSONRPCHandler']

Then place everything in Dockerfile like so:

    FROM kiwitcms/kiwi

    COPY ./api_logging/ /venv/lib64/python3.6/site-packages/api_logging/
    COPY local_settings.py /venv/lib64/python3.6/site-packages/tcms/settings/

Kiwi TCMS will import your local_settings.py and enable the logging application. Now build your customized Docker image and use it for deployment!

Happy testing!

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