2. Configuration

This chapter provides guidance for configuring a GeoHealthCheck instance.

2.1. Configuration Parameters

The core configuration is in GeoHealthCheck/config_main.py. Optionally override these settings for your instance in instance/config_site.py. You can specify a configuration file in the environment settings that will override settings in both previous files. The configuration options are:

  • SQLALCHEMY_DATABASE_URI: the database configuration. See the SQLAlchemy documentation for more info

  • SECRET_KEY: secret key to set when enabling authentication. Use the output of paver create_secret_key to set this value

  • GHC_RETENTION_DAYS: the number of days to keep Run history

  • GHC_PROBE_HTTP_TIMEOUT_SECS: stop waiting for the first byte of a Probe response after the given number of seconds

  • GHC_MINIMAL_RUN_FREQUENCY_MINS: minimal run frequency for Resource that can be set in web UI

  • GHC_SELF_REGISTER: allow registrations from users on the website

  • GHC_NOTIFICATIONS: turn on email notifications

  • GHC_NOTIFICATIONS_VERBOSITY: receive additional email notifications than just Failing and Fixed (default True)

  • GHC_WWW_LINK_EXCEPTION_CHECK: turn on checking for OGC Exceptions in WWW:LINK Resource responses (default False)

  • GHC_ADMIN_EMAIL: email address of administrator / contact- notification emails will come from this address

  • GHC_NOTIFICATIONS_EMAIL: list of email addresses that notifications should come to. Use a different address to GHC_ADMIN_EMAIL if you have trouble receiving notification emails. Also, you can set separate notification emails to specific resources. Failing resource will send notification to emails from GHC_NOTIFICATIONS_EMAIL value and emails configured for that specific resource altogether.

  • GHC_SITE_TITLE: title used for installation / deployment

  • GHC_SITE_URL: full URL of the installation / deployment

  • GHC_SMTP: configure SMTP settings if GHC_NOTIFICATIONS is enabled

  • GHC_RELIABILITY_MATRIX: classification scheme for grading resource

  • GHC_PLUGINS: list of Core/built-in Plugin classes or modules available on installation

  • GHC_USER_PLUGINS: list of Plugin classes or modules provided by user (you)

  • GHC_PROBE_DEFAULTS: Default Probe class to assign on “add” per Resource-type

  • GHC_METADATA_CACHE_SECS: metadata, “Capabilities Docs”, cache expiry time, default 900 secs, -1 to disable

  • GHC_REQUIRE_WEBAPP_AUTH: require authentication (login or Basic Auth) to access GHC webapp and APIs (default: False)

  • GHC_BASIC_AUTH_DISABLED: disable Basic Authentication to access GHC webapp and APIs (default: False), see below when to set to True

  • GHC_RUNNER_IN_WEBAPP: should the GHC Runner Daemon be run in webapp (default: True), more below

  • GHC_LOG_LEVEL: logging level: 10=DEBUG 20=INFO 30=WARN(ING) 40=ERROR 50=FATAL/CRITICAL (default: 30, WARNING)

  • GHC_MAP: default map settings

    • url: URL of TileLayer

    • centre_lat: Centre latitude for homepage map

    • centre_long: Centre longitude for homepage map

    • maxzoom: maximum zoom level

    • subdomains: available subdomains to help with parallel requests

Example on overriding the configuration with an environment variable:

export GHC_SETTINGS=/tmp/my_GHC_settings.py
paver run_tests

As an example: the my_GHC_settings.py file can contain a single line to define a test database:

SQLALCHEMY_DATABASE_URI='sqlite:////tmp/GHCtest.db'

NOTE: do not forget to reset the environment variable afterwards.

2.2. Email Configuration

A working email-configuration is required for notifications and password recovery. This can sometimes be tricky, below is a working configuration for the GMail account my_gmail_name@gmail.com.

GHC_SMTP = {
    'server': 'smtp.gmail.com',
    'port': 587,
    'tls': True,
    'ssl': False,
    'username': 'my_gmail_name@gmail.com',
    'password': '<my gmail password>'
}

In your Google Account settings for that GMail address you should turn on “Allow less secure apps” as explained here.

2.3. Healthcheck Scheduling

Healthchecks (Runs) for each Resource can be scheduled via cron or (starting with v0.5.0) by running the GHC Runner app standalone (as daemon) or within the GHC Webapp.

2.3.1. Scheduling via Cron

Applies only to pre-0.5.0 versions.

Edit the file jobs.cron so that the paths reflect the path to the virtualenv. Set the first argument to the desired monitoring time step. If finished editing, copy the command line calls e.g. /YOURvirtualenv/bin_or_SCRIPTSonwindows/python /path/to/GeoHealthCheck/GeoHealthCheck/healthcheck.py run to the commandline to test if they work sucessfully. On Windows - do not forget to include the ‘’.exe.’’ file extension to the python executable. For documentation how to create cron jobs see your operating system: on *NIX systems e.g. crontab -e and on windows e.g. the nssm.

NB the limitation of cron is that the per Resource schedule cannot be applied as the cron job will run healthchecks on all Resources.

2.3.2. GHC Runner as Daemon

In this mode GHC applies internal scheduling for each individual Resource. This is the preferred mode as each Resource can have its own schedule (configurable via Dashboard) and cron has dependencies on local environment. Later versions may phase out cron-scheduling completely.

The GHC Runner can be run via the command paver runner_daemon or can run internally within the GHC Webapp by setting the config variable GHC_RUNNER_IN_WEBAPP to True (the default). NB it is still possible to run GHC as in the pre-v0.5.0 mode using cron-jobs: just run the GHC Webapp with GHC_RUNNER_IN_WEBAPP set to False and have your cron-jobs scheduled.

In summary there are three options to run GHC and its healthchecks:

  • run GHC Runner within the GHC Webapp: set GHC_RUNNER_IN_WEBAPP to True and run only the GHC webapp

  • (recommended): run GHC Webapp and GHC Runner separately (set GHC_RUNNER_IN_WEBAPP to False)

  • (deprecated): run GHC Webapp with GHC_RUNNER_IN_WEBAPP set to False and schedule healthchecks via external cron-jobs

2.4. Language Translations

GHC supports multiple languages by using [Babel](http://babel.pocoo.org) with [Flask-Babel](https://pythonhosted.org/Flask-Babel/).

“Babel is an integrated collection of utilities that assist in internationalizing and localizing Python applications, with an emphasis on web-based applications.”

2.4.1. Enabling/Disabling a Language

Open the file GeoHealthCheck/app.py and look for the language switcher (e.g. ‘en’,’fr’) and remove or add the desired languages. In case of a new language, a new translation file (called a *.po) has to be added as follows:

  • make a copy of one of the folders in GeoHealthCheck/translations/;

  • rename the folder to the desired language (e.g. ‘de’ for German) using the language ISO codes

  • edit the file <your_lang>/LC_MESSAGES/messages.po, adding your translations to the msgstr

Don’t forget the change the specified language in the messages.po file as well. For example the messages.po file for the German case has an English msgid string, which needs to be translated in msgstr’ as seen below.

#: GeoHealthCheck/app.py:394
msgid "This site is not configured for self-registration"
msgstr "Diese Webseite unterstützt keine Selbstregistrierung"

2.4.2. Compiling Language Files

At runtime compiled versions, *.mo files, of the language-files are used. Easiest to compile is via: paver compile_translations in the project root dir. This basically calls ``pybabel compile` with the proper options. Now you can e.g. test your new translations by starting GHC.

2.4.3. Updating Language Files

Once a language-file (.po) is present, it will need updating as development progresses. In order to know what to update (which strings are untranslated) it best to first update the messages.po file with all language strings, their location(s) within project files and whether the translation is missing. Missing translations will have msgstr “” like in this excerpt:

#: GeoHealthCheck/notifications.py:245 GeoHealthCheck/notifications.py:247
msgid "Passing"
msgstr "Jetzt geht's"

#: GeoHealthCheck/plugins/probe/ghcreport.py:115
msgid "Status summary"
msgstr ""

Next all empty `msgstr`s can be filled.

Updating is easiest using the command paver update_translations within the root dir of the project. This will basically call pybabel extract followed by pybabel update with the proper parameters.

2.5. Customizing the Score Matrix

GeoHealthCheck uses a simple matrix to provide an indication of overall health and / or reliability of a resource. This matrix drives the CSS which displays a given resource’s state with a colour. The default matrix is defined as follows:

low

high

score/colour

0

49

red

50

79

orange

80

100

green

To adjust this matrix, edit GHC_RELIABILITY_MATRIX in instance/config_site.py.

2.6. Securing GHC Webapp

In some cases it is required that only logged-in (authenticated) users like the admin user can access the entire GHC webapp and its APIs. In that case the config setting GHC_REQUIRE_WEBAPP_AUTH should be set to True. (version 0.7+). Non-authenticated users will be presented with the login screen. Initially only the admin user will be able to login, but it is possible to register and allow additional users by registering these within the admin login session. Note that password reset is still enabled. For remote REST API calls standard HTTP Basic Authentication (via the HTTP Authentication request header) can be used.

In some cases where an external web- or proxy server provides HTTP Basic Authentication, a conflict may arise when GHC also checks the Authorization HTTP header used for the external Basic Auth. In those cases GHC Basic Auth checking can be disabled using the GHC_BASIC_AUTH_DISABLED to True. TODO: provide API Token auth to allow both external Basic Auth and GHC API auth.