Healthchecks

healthchecks is a watchdog for your cron jobs. It's a web server that listens for pings from your cron jobs, plus a web interface.

It is live here: http://healthchecks.io/

The building blocks are:

• Python 3
• Django 2
• PostgreSQL or MySQL

Setting Up for Development

These are instructions for setting up healthchecks Django app in development environment.

• install dependencies (Debian/Ubuntu)

    $ sudo apt-get update
    $ sudo apt-get install -y gcc python3-dev python3-venv
  

• prepare directory for project code and virtualenv:

    $ mkdir -p ~/webapps
    $ cd ~/webapps
  

• prepare virtual environment (with virtualenv you get pip, we'll use it soon to install requirements):

    $ python3 -m venv hc-venv
    $ source hc-venv/bin/activate
  

• check out project code:

    $ git clone https://github.com/healthchecks/healthchecks.git
  

• install requirements (Django, ...) into virtualenv:

    $ pip install -r healthchecks/requirements.txt
  

• healthchecks is configured to use a SQLite database by default. To use PostgreSQL or MySQL database, create and edit hc/local_settings.py file. There is a template you can copy and edit as needed:

    $ cd ~/webapps/healthchecks
    $ cp hc/local_settings.py.example hc/local_settings.py
  

• create database tables and the superuser account:

    $ cd ~/webapps/healthchecks
    $ ./manage.py migrate
    $ ./manage.py createsuperuser
  

• run development server:

    $ ./manage.py runserver
  

The site should now be running at http://localhost:8080 To log into Django administration site as a super user, visit http://localhost:8080/admin

Configuration

Site configuration is loaded from environment variables. This is done in hc/settings.py. Additional configuration is loaded from hc/local_settings.py file, if it exists. You can create this file (should be right next to settings.py in the filesystem) and override settings, or add extra settings as needed.

Configurations settings loaded from environment variables:

Environment variable	Default value	Notes
SECRET_KEY	"---"
DEBUG	True	Set to False for production
ALLOWED_HOSTS	*	Separate multiple hosts with commas
DEFAULT_FROM_EMAIL	"[email protected]"
USE_PAYMENTS	False
REGISTRATION_OPEN	True
DB	"sqlite"	Set to "postgres" or "mysql"
DB_HOST	"" (empty string)
DB_PORT	"" (empty string)
DB_NAME	"hc" (PostgreSQL, MySQL) or "/path/to/project/hc.sqlite" (SQLite)	For SQLite, specify the full path to the database file.
DB_USER	"postgres" or "root"
DB_PASSWORD	"" (empty string)
DB_CONN_MAX_AGE	0
DB_SSLMODE	"prefer"	PostgreSQL-specific, details
DB_TARGET_SESSION_ATTRS	"read-write"	PostgreSQL-specific, details
EMAIL_HOST	"" (empty string)
EMAIL_PORT	"587"
EMAIL_HOST_USER	"" (empty string)
EMAIL_HOST_PASSWORD	"" (empty string)
EMAIL_USE_TLS	"True"
EMAIL_USE_VERIFICATION	"True"
SITE_ROOT	"http://localhost:8000"
SITE_NAME	"Mychecks"
MASTER_BADGE_LABEL	"Mychecks"
PING_ENDPOINT	"http://localhost:8000/ping/"
PING_EMAIL_DOMAIN	"localhost"
DISCORD_CLIENT_ID	None
DISCORD_CLIENT_SECRET	None
SLACK_CLIENT_ID	None
SLACK_CLIENT_SECRET	None
PUSHOVER_API_TOKEN	None
PUSHOVER_SUBSCRIPTION_URL	None
PUSHOVER_EMERGENCY_RETRY_DELAY	300
PUSHOVER_EMERGENCY_EXPIRATION	86400
PUSHBULLET_CLIENT_ID	None
PUSHBULLET_CLIENT_SECRET	None
TELEGRAM_BOT_NAME	"ExampleBot"
TELEGRAM_TOKEN	None
TWILIO_ACCOUNT	None
TWILIO_AUTH	None
TWILIO_FROM	None
TWILIO_USE_WHATSAPP	"False"
PD_VENDOR_KEY	None
TRELLO_APP_KEY	None
MATRIX_HOMESERVER	None
MATRIX_USER_ID	None
MATRIX_ACCESS_TOKEN	None

Some useful settings keys to override are:

SITE_ROOT is used to build fully qualified URLs for pings, and for use in emails and notifications. Example:

SITE_ROOT = "https://my-monitoring-project.com"

SITE_NAME has the default value of "Mychecks" and is used throughout the templates. Replace it with your own name to personalize your installation. Example:

SITE_NAME = "My Monitoring Project"

REGISTRATION_OPEN controls whether site visitors can create new accounts. Set it to False if you are setting up a private healthchecks instance, but it needs to be publicly accessible (so, for example, your cloud services can send pings).

If you close new user registration, you can still selectively invite users to your team account.

EMAIL_USE_VERIFICATION enables/disables the sending of a verification link when an email address is added to the list of notification methods. Set it to False if you are setting up a private healthchecks instance where you trust your users and want to avoid the extra verification step.

Database Configuration

Database configuration is loaded from environment variables. If you need to use a non-standard configuration, you can override the database configuration in hc/local_settings.py like so:

DATABASES = {
    'default': {
        'ENGINE':   'django.db.backends.postgresql',
        'NAME':     'your-database-name-here',
        'USER':     'your-database-user-here',
        'PASSWORD': 'your-database-password-here',
        'TEST': {'CHARSET': 'UTF8'},
        'OPTIONS': {
            ... your custom options here ...
        }
    }
}

Sending Emails

healthchecks must be able to send email messages, so it can send out login links and alerts to users. Environment variables can be used to configure SMTP settings, or your may put your SMTP server configuration in hc/local_settings.py like so:

EMAIL_HOST = "your-smtp-server-here.com"
EMAIL_PORT = 587
EMAIL_HOST_USER = "username"
EMAIL_HOST_PASSWORD = "password"
EMAIL_USE_TLS = True

For more information, have a look at Django documentation, Sending Email section.

Receiving Emails

healthchecks comes with a smtpd management command, which starts up a SMTP listener service. With the command running, you can ping your checks by sending email messages to [email protected] email addresses.

Start the SMTP listener on port 2525:

$ ./manage.py smtpd --port 2525

Send a test email:

$ curl --url 'smtp://127.0.0.1:2525' \
    --mail-from '[email protected]' \
    --mail-rcpt '[email protected]' \
    -F '='

Sending Status Notifications

healtchecks comes with a sendalerts management command, which continuously polls database for any checks changing state, and sends out notifications as needed. Within an activated virtualenv, you can manually run the sendalerts command like so:

$ ./manage.py sendalerts

In a production setup, you will want to run this command from a process manager like supervisor or systemd.

Database Cleanup

With time and use the healthchecks database will grow in size. You may decide to prune old data: inactive user accounts, old checks not assigned to users, records of outgoing email messages and records of received pings. There are separate Django management commands for each task:

• Remove old records from api_ping table. For each check, keep 100 most recent pings:

  $ ./manage.py prunepings
  

• Remove old records of sent notifications. For each check, remove notifications that are older than the oldest stored ping for same check.

  $ ./manage.py prunenotifications
  

• Remove user accounts that match either of these conditions:

  • Account was created more than 6 months ago, and user has never logged in. These can happen when user enters invalid email address when signing up.

  • Last login was more than 6 months ago, and the account has no checks. Assume the user doesn't intend to use the account any more and would probably want it removed.

    $ ./manage.py pruneusers
    

• Remove old records fromt he api_tokenbucket table. The TokenBucket model is used for rate-limiting login attempts and similar operations. Any records older than one day can be safely removed.

  $ ./manage.py prunetokenbucket
  

When you first try these commands on your data, it is a good idea to test them on a copy of your database, not on the live database right away. In a production setup, you should also have regular, automated database backups set up.

Integrations

Discord

To enable Discord integration, you will need to:

• register a new application on https://discordapp.com/developers/applications/me
• add a redirect URI to your Discord application. The URI format is SITE_ROOT/integrations/add_discord/. For example, if you are running a development server on localhost:8000 then the redirect URI would be http://localhost:8000/integrations/add_discord/
• Look up your Discord app's Client ID and Client Secret. Put them in DISCORD_CLIENT_ID and DISCORD_CLIENT_SECRET environment variables.

Pushover

To enable Pushover integration, you will need to:

• register a new application on https://pushover.net/apps/build
• enable subscriptions in your application and make sure to enable the URL subscription type
• put the application token and the subscription URL in PUSHOVER_API_TOKEN and PUSHOVER_SUBSCRIPTION_URL environment variables

Telegram

• Create a Telegram bot by talking to the BotFather. Set the bot's name, description, user picture, and add a "/start" command.

• After creating the bot you will have the bot's name and token. Put them in TELEGRAM_BOT_NAME and TELEGRAM_TOKEN environment variables.

• Run settelegramwebhook management command. This command tells Telegram where to forward channel messages by invoking Telegram's setWebhook API call:

  $ ./manage.py settelegramwebhook
  Done, Telegram's webhook set to: https://my-monitoring-project.com/integrations/telegram/bot/
  

For this to work, your SITE_ROOT needs to be correct and use "https://" scheme.