====================
Website checker demo
====================

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   :target: https://github.com/vladan/aiven-site-checker/actions?query=workflow%3Aunittests+branch%3Amaster

.. image:: https://github.com/vladan/aiven-site-checker/workflows/documentation/badge.svg
   :target: https://vladan.github.io/aiven-site-checker/

CHWEB is a website checking tool.

It sends HTTP requests to sites with the intent to check their status /
availibility, and if the ``regex`` param is specified, it runs it against the
response body. The retreived status check is sent to a Kafka topic. When
read by the consumer, the status check is written in a PostgreSQL database.

ATM in its very early stages meant to demo `aiven <https://aiven.io>`_'s
platform, using their `kafka <https://aiven.io/kafka>`_ and `postgresql
<https://aiven.io/postgresql>`_ services.


Quickstart with docker-compose
==============================

The services can be run with docker-compose. You'd need to change the values of
``KAFKA_SERVERS``, ``POSTGRES_HOST`` and ``POSTGRES_PASS`` in order for
the configuration to be properly applied. Also, you'd need to download the
kafka certificates and put them in the folder you're running docker-composer
from and create the PostgreSQL cert by copying it from aivens console and
saving it to ``pgcert.pem``. After all this is done, simply run::

    docker-compose up

No docker?
----------

if you haven't got, or don't want to use docker, then you can install this
package and run it manually.

Install the latest dev version from the github repository::

    pip install git+https://github.com/vladan/aiven-site-checker.git

Run the website status collector in one terminal::

    chweb_collect -c config.yaml

and the consumer in another::

    chweb_consume -c config.yaml

Config file
===========

There's an example config file in the top-level dir of the repository, named
``config.yaml`` that you can use as a reference. Some explanation on the main
sections are listed below.

Sites
-----

.. highlight:: yaml

You can specify the sites you want checked in the yaml config file. They are
stored in the ``sites`` key and are represented as a list of objects with
``url`` and ``check_interval`` as mandatory fields, and regex as an optional
field that can freely omitted which checks the body of the response against the
regex expression::

  - url: "https://example.com"
    regex: "domain" # a regex matching the body of the response
    check_interval: 5
  - url: "https://example.com"
    regex: "aaaaaaaa" # a regex not matching the body of the response
    check_interval: 8
  - url: "https://example.com/404"
    check_interval: 13

Logging configuration
---------------------

The ``logging`` section must be present. A simple example of a console logger
as seen in ``config.yaml``::

    logging:
      version: 1
      formatters:
        standard:
          format: "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
        error:
          format: "%(levelname)s <PID %(process)d:%(processName)s> %(name)s.%(funcName)s(): %(message)s"
      handlers:
        console:
          class: logging.StreamHandler
          level: DEBUG
          formatter: standard
          stream: ext://sys.stdout
      root:
        level: DEBUG
        handlers: [console]
        propogate: yes

Postgres
--------

Postgres settings with aivens certs, passwords, etc. You'll get them once you
setup the postgres service on https://console.aiven.io/. My postgres section
in the config looks like this::

    postgres:
      dbhost: "pg-2e0f365c-vladanovic-4654.aivencloud.com"
      dbport: 23700
      dbname: "defaultdb"
      dbuser: "avnadmin"
      dbpass: "..."
      dbcert: "./certs/pg.pem"

* ``dbhost`` and ``dbport``, ``dbuser`` and ``dbpass`` are straightforward.
* ``defaultdb`` is the database present by default, when the service is
  created. You can create another database if it rocks your boat.
* ``dbcert`` is the cert which opens in a modal popup in the console. You need
  to copy it manually to a file on a path you later state in the config.

Kafka
-----

Kafka is also a service easily provisioned through aivens console. After it's
set up you get a config section similar to this one::

    kafka:
      servers:
      - "kafka-f7ae38e-vladanovic-4654.aivencloud.com:23702"
      topic: "sitestats"
      cafile: "./certs/ca.pem"
      cert: "./certs/service.cert"
      key: "./certs/service.key"
      passwd: "..."

* ``servers`` is a list because that's how the library is initialized, which
  makes sense if you have multiple brokers.
* ``topic`` is the kafka topic messages are sent to. You need to define it in
  aivens console as well.
* ``cafile``, ``cert`` and ``key`` are the ssl certificates you get when aivens
  kafka service is ready.
* ``password`` your aiven provided password.